No.672/476, 8 th FLOOR, TEMPLE TOWER, ANNA SALAI, NANDANAM, CHENNAI , TAMIL NADU, INDIA.

Transcription

1 TAMILNADU GENERATION AND DISTRIBUTION CORPORATION LIMITED (TANGEDCO) CHENNAI, TAMIL NADU DETAILED PROJECT REPORT FOR ESTABLISHING ENNORE SEZ PROJECT OF 2 x 800 MW COAL BASED SUPER CRITICAL THERMAL POWER PROJECT AT ASH DYKE OF NORTH CHENNAI THERMAL POWER STATION APRIL CETHAR CONSULTING ENGINEERS LIMITED, No.672/476, 8 th FLOOR, TEMPLE TOWER, ANNA SALAI, NANDANAM, CHENNAI , TAMIL NADU, INDIA.

2 PROJECT: ENNORE SEZ PROJECT OF 2 X 800 MW COAL BASED SUPER CRITICAL THERMAL POWER PROJECT AT ASH DYKE OF NCTPS TITLE: DETAILED PROJECT REPORT CLIENT : TAMIL NADU GENERATION AND DISTRIBUTION CORPORATION LIMITED (TANGEDCO) CONSULTANT : CETHAR CONSULTING ENGINEERS LIMITED NANDANAM, CHENNAI WORK ORDER NO : TOTAL NO OF PAGES : (including Contents and Drawings) Final D. Dinesh Kumar G. A. Vinoth A. Ekambaram Final P. Sathesh Kumar G. A. Vinoth A. Ekambaram Draft P. Sathesh Kumar G. A. Vinoth A. Ekambaram Rev. No Date Prepared By Checked By Approved By Description

3 Contents Section No Description Page No Project Highlights Introduction Background Restructuring of TNEB Scope of this Report Executive Summary Summary Project Information table Need for the Project Power Need for Life National Electricity Policy Indian Power Scenario Mega Power Status Benefits of the Project Government / Statutory Approvals Acknowledgment Need & Justification of this Project Site Selection Study Factors for Site Selection Details of Proposed Site and infrastructure Environmental Considerations Selection Technology for Main Plant Equipment Technology Selection Selection of Steam Generator 02 Contents Page 1 of 6

4 Section No Description Page No Steam Generator - Pulverized Fuel Fired Boilers Introduction of Supercritical Technology Effect on Supercritical Technology design Spiral Wound Universal Pressure (SWUP) Boiler Vertical Tube Universal Pressure (VTUP) Boiler Advantages of Supercritical technology over subcritical technology Conclusion Selection Technology for Steam Turbine Steam Cycle Configuration for this Plant Supercritical Plant Manufacturers in India Supercritical Plant, Manufacturer outside India Delivery Periods Technical Features of the Main Plant General Heat Balance Steam Generating Units Steam Turbine Generator ( STG ) Technical features of Balance of Plants Mechanical systems Electrical systems Control & Instrumentation Civil & Structural works Plant Layout Arrangements Plant General Layout Arrangement 01 Contents Page 2 of 6

5 Section No Description Page No Environmental Issues & Management Plan Environmental considerations Atmospheric Pollution Pollution due to discharge of liquid and solid wastes Fly Ash Management Regulations for limiting Air Pollution Indian Standards National Ambient Air Quality Standards Water Pollution Thermal Power Plant: Standards for Liquid Effluents Temperature Limit for Discharge of Condenser Cooling Water From Thermal Power Plant Effluent Recycle and Reuse System Guidelines for Discharge point Noise Pollution Air Quality Monitoring Programme Water Quality Monitoring Programme Impact of Pollution / Environmental disturbances Environmental Management Plan Execution & Project Management Construction Facilities Requirement Execution Methodology Procurement Procedure Project Implementation schedule O & M Management Training 06 Contents Page 3 of 6

6 Section No Description Page No Clean Development Mechanism (CDM) Clean Development Mechanism Cost Estimate and Financial Analysis Cost Estimate 01 Annexure Sl. No Description No. of Pages 4.1 Copy of CMWSSB Clearance Copy of AAI Clearance Location Map of the Project Raw Water Analysis Fuel Analysis 02 Costing 13.1 Cost Estimate and Financial analysis Phasing of Expenditure & IDC Calculation Tariff Calculation Blended Fuel (70% Indian + 30% Imported) Tariff Calculation Blended Fuel (30% Indian + 70% Imported) 04 Sub Total no of Pages 20 Contents Page 4 of 6

7 List of Drawings S. No Title Drawing No. No. of Pages 1. Plot Plan CCE ME SG & TG Sectional view CCE ME TG Building Floor plan CCE ME Heat and Mass Balance Diagram CCE ME Process Flow Diagram CCE ME Fuel System Flow Diagram CCE ME Coal Handling scheme CCE ME Bottom Ash handling Scheme CCE ME Fly Ash handling Scheme CCE ME Emergency Ash Disposal Scheme CCE ME Raw Water System Flow Diagram CCE ME Water Balance Diagram CCE ME Condenser Cooling & Auxiliary Cooling Water Scheme CCE ME Waste Water Management Scheme CCE ME Scheme For Fuel Oil System CCE ME (Sheet 1 of 2) Scheme For Fuel Oil System CCE ME (Sheet 2 of 2) 17. Air Compressor Scheme CCE ME Fire Protection System CCE ME Main One Line Diagram 20. Main One Line Diagram CCE EL (Sheet 1 of 2) CCE EL (Sheet 2 of 2) DDCMIS System Configuration For Composite C&I Package (UNIT-I) CCE C&I (Sheet 1 of 2) Common System For Unit-I & II CCE CI (Sheet 2 of 2) PLC System Configuration Diagram CCE CI Plant Security Surveillance System CCE CI Contents Page 5 of 6

8 S. No Title Drawing No. No. of Pages 25. Organization Chart CCE ME Organization Chart for O & M CCE ME Project Schedule CCE ME Sub Total no of Pages 27 Contents Page 6 of 6

9 Section 1 Project Highlights 1.0 Project Information & Location 1.1 Project Title : Ennore SEZ project of 2 x 800 MW Coal Based Super Critical Thermal Power Project at ash dyke of NCTPS 1.2 Plant capacity : 1600 MW (2 units of 800 MW each) 1.3 Type of project : Green field 1.4 Owner : Tamil Nadu Generation and Distribution Corporation Limited (TANGEDCO) 1.5 Plant site location : Ash dyke of North Thermal Power Station (NCTPS) 1.6 Location co-ordinates : E to E Longitude N to N Latitude 1.7 Nearest Village : Vayalur 1.8 Nearest Town & City : (35 Km) 1.9 State Capital : (35 Km) 1.10 Nearest Railway Station : Athipattu Pudunagar (~ 5 Km) 1.11 Nearest Airport : (~ 60 Km) 1.12 Nearest Seaport : Ennore (~ 5 Km) 1.13 Nearest Road access : All weather road from Pattamandri on the Thiruvottiyur Ponneri district highway 2.0 Meteorological Condition 2.1 Climate : Tropical, very dry and hot summer, dry and cold winter and good rain-fall in monsoon accompanied with strong wind Section - 1 Page 1 of 9

10 2.2 Site Elevation : (+) 10.0 Meter above Mean Sea Level 2.3 Ambient Temperature a. Annual Maximum Mean Temperature b. Annual Minimum Mean Temperature : 32 ºC : 24 ºC c. Design ambient temperature : 35 ºC 2.4 Relative Humidity a. Maximum : 100 % b. Minimum : 36 % c. Design : 75 % 2.5 Annual Rainfall Maximum : 2540 mm Average : 1600 mm Minimum : 1175 mm 2.6 Prevailing Wind Direction : November to January From NW & NE February to March From East & SE April to May From South & SE June From SW July to August From NW September to October From SE & SW 2.7 Wind Speed : 11.8 kmph (Avg), 50 m/s (max) 2.7 Seismic zone : Zone: III as defined in IS: Design ambient temperature for Electrical equipments : 50 C Section - 1 Page 2 of 9

11 3.0 Fuel Source & transportation for 2 x 800 MW 3.1 Source of Fuel a. Option - I : 100% Indian coal from Kalinga Block of Talcher coal fields, Mahanadhi and IB valley coal fields b. Option - II : 100% Imported coal c. Option - III : Blended Fuel 70% Indian coal & 30% Imported coal d. Option - IV : Blended Fuel 70% Imported coal & 30% Indian coal e. Support fuel : Heavy Furnace Oil (HFO) and Light Diesel Oil (LDO) from nearest depot / source 3.2 Fuel transportation : Coal can be transported from coal mines to Ennore port by sea and unloaded at proposed coal berth III, further the coal can be transported to proposed power plant through conveyor. 3.3 Fuel Calorific Value a. Indian coal : 3100 kcal/kg b. Imported coal : 5500 kcal/kg c. Blended fuel (70% Indian coal & 30% Imported coal) d. Blended fuel (70% Imported coal & 30% Indian coal) : 3820 Kcal / kg : 4780 Kcal / kg 4.0 Fuel Consumption 4.1 Option - I : 100% Indian coal a. Fuel Consumption Per Boiler : 542 TPH b. Fuel Consumption for Two (2) Nos. of Boiler : 1084 TPH c. Fuel Consumption per annum : : Million tons at 100 % PLF load Million tons at 85 % PLF load Section - 1 Page 3 of 9

12 4.2 Option - II : 100% Imported coal a. Fuel Consumption Per Boiler : TPH b. Fuel Consumption for Two (2) Nos. of Boiler : 611 TPH c. Fuel Consumption per annum : : Million tons at 100 % PLF load Million tons at 85 % PLF load 4.3 Option - III : Blended (70% Indian coal & 30% Imported coal) a. Fuel Consumption Per Boiler : 440 TPH b. Fuel Consumption for Two (2) Nos. of Boiler : 880 TPH c. Fuel Consumption per annum : : Million tons at 100 % PLF load Million tons at 85 % PLF load 4.4 Option - IV : Blended (70% Imported coal & 30% Indian coal) Fuel Consumption Per Boiler : 351 TPH Fuel Consumption for Two (2) Nos. of Boiler : 703 TPH Fuel Consumption per annum : : Million tons at 100 % PLF load Million tons at 85 % PLF load 4.5 Coal storage days at site : 15 days 4.6 Size of Coal stock pile in mtrs : 50 (w) x 700 (l) x 10 (h) 4.7 Support fuel required (HFO) per annum : KL 5.0 Ash Generation 5.1 % of Ash content in Indian coal : 45% (Worst Condition) 5.2 Ash generation per boiler : 244 TPH 5.3 Ash generation for Two (2) : 488 TPH Section - 1 Page 4 of 9

13 Nos. of Boiler 5.4 Total Ash generation per annum : Million tonnes 5.5 Ash utilisation : 100% commercial applications 6.0 Water Source and Quantity 6.1 Option I : Sea water from existing fore bay of NCTPS Stage II for cooling tower make-up. Metro Water Supply & Sewerage Board Water for boiler cycle make-up and other utilities. a. Water requirement for cooling tower make-up b. Water requirement for boiler cycle make-up & other utilities : m 3 /hr : 1030 m 3 /hr 6.2 Option II : Sea water a. Total raw water requirement : m 3 /hr 7.0 Land 7.1 Total Land required in acres : 500 (Land is under possession of TANGEDCO) 8.0 Plant Equipment 8.1 Boiler & Auxiliaries a. Boiler : Pulverized Coal (PC) fired Boiler b. Type : Once through sliding pressure supercritical boiler, Vertical wall evaporator with rifle tubing, Conventional Two-pass, Single reheat, Balanced draft and drumless type unit suitable for outdoor installation c. Steam Parameters per Boiler : Flow 2600 TPH Pressure 256 ATA Temperature 568 / 595 o C Section - 1 Page 5 of 9

14 d. Boiler Efficiency : 85% 8.2 Turbine & Auxiliaries a. Turbine : Horizontally split, multi cylinder design with throttle governing (one HP, one IP & two LP) 3000 rpm multistage, tandem compound, single reheat, double condensing type unit uncontrolled extractions for regenerative feed heating able to generate 800 MW of each unit. b. Electrical Generator : Two-pole, hydrogen-cooled turbo generator with direct water cooling for the stator winding, which is directly coupled to the turbines, a rotating-diode brushless excitation system, 50 Hz., 3000, 3 phase, 0.85 power factor (lagging), 27 KV. c. Steam Parameters per Boiler : Pressure 247 ATA Temperature 565 / 593 o C d. Turbine heat rate : 1850 Kcal / kwh e. Plant heat rate : 2100 kcal / kwh 8.3 Coal Handling System a. Design Capacity (Worst condition) : 2000 TPH for 16 hours operation for 100% Indian coal with Two (2) Streams (1W + 1S) 8.4 Ash Handling System a. Bottom Ash : Pneumatic conveying with dry disposal system b. Fly Ash : Pneumatic conveying with dry disposal system 8.5 Cooling Tower a. Type : Natural draft Cooling Tower b. No. of Cooling Tower : One (01) No. for each unit b. Capacity : m 3 /hr for each unit Section - 1 Page 6 of 9

15 8.6 Chimney a. No. of Chimney : One (01) Twin flue chimney b. Height of Chimney : 275 meter (RCC Structure) 9.0 Power Evacuation a. Power Evacuation : Through 400 kv GIS to nearby substation 10.0 Project Schedule a. Unit 1 Commissioning date : 48 Months from zero date COD of unit : 51 Months from zero date b. Unit 2 Commissioning & COD date : Phase shift of Six months from the zero date of Unit Manpower Requirement a. During Construction Technical Non Technical b. During O & M Technical Non Technical : : : : 50 Personnel 250 Personnel 100 Personnel 450 Personnel 12.0 Annual Power Generation for 2 x 800 MW 12.1 Gross Generation at 100% Plant Load Factor 12.2 Gross Generation at 85% Plant Load Factor 12.3 Auxiliary Consumption 6% : million kwh : million kwh : million kwh 12.4 Net Units sent Out per annum : million kwh Section - 1 Page 7 of 9

16 13.0 Costing 13.1 Project cost without IDC : Rs Crores 13.2 Cost per MW without IDC : Rs Crores 13.3 Syndicate 0.4% & Upfront 0.1% 13.4 Total Project Cost without IDC including upfront fees & Bankers fees : Rs Crores : Rs Crores 13.5 IDC : Total project Cost with IDC : Rs Crores 13.7 Cost per MW with IDC : Rs.6.97 Crores 13.8 Moratorium Period : 6 Months 13.9 Cost of Generation : Condition I (Blended Fuel 70% Indian + 30% Imported) a. GCV of Blended Fuel : 3820 Kcal/kg b. Cost of fuel : Rs per ton c. Cost of 85% PLF : Rs per unit d. Levellised 85% PLF : Rs per unit Condition II (Blended Fuel - 30% Indian + 70% Imported) a. GCV of Blended Fuel : 4780 Kcal/kg b. Cost of fuel : Rs per ton c. Cost of 85% PLF : Rs per unit d. Levellised 85% PLF : Rs per unit Condition III (100% Indian Coal) a. GCV of Indian coal : 3100 Kcal/kg b. Cost of fuel : Rs per ton c. Cost of 85% PLF : Rs per unit d. Levellised 85% PLF : Rs per unit Section - 1 Page 8 of 9

17 Condition IV (100% Imported Coal) a. GCV of Imported Coal : 5500 Kcal/kg b. Cost of fuel : Rs per ton c. Cost of 85% PLF : Rs per unit d. Levellised 85% PLF : Rs per unit Section - 1 Page 9 of 9

18 Section 2 Introduction Background In view of acute shortage of power in the State and in order to bridge the demand availability gap of power, Tamil Nadu Electricity Board (TNEB) is exploring the possibility of establishing one or two thermal power projects. TNEB proposed to establish coal based thermal power plants near Ennore port area to utilize the available Infrastructure facilities of the port as well as facilities developed by TNEB in that region. The Industries Department was agreeable in-principle to allot about 500 acres of land in the TIDCO's Multi product special Economic Zone in Thiruvallur District for setting up of thermal plants. It was proposed to set up 2 units of 600 MW capacity in the TIDCO land in Thiruvallur District, under State Sector at the project cost of about Rs.6000 Crores. In this context Board has accorded approval vide per. B.P. (FB) No. 1 (Tech branch) dt for the following: To set up 2 units of 600 MW capacity each in the Ennore Multi product Special Economic Zone proposed by TIDCO in Thiruvallur District, under State Sector. To approach Govt. of Tamil Nadu for obtaining approval for setting up the 2 x 600 MW Thermal Power Project in TIDCO land in Thiruvallur District. To undertake the demarcation of the site under Coastal Regulation Zone (CRZ) to arrive at the actual area available for setting up a Thermal power project and other preliminary investigations at a cost of Rs Lakhs. As the proposed site of TIDCO near NCTPS for the captioned project was not suitable as per CRZ Regulations 1991, an alternate possibility was explored to identify the site for setting up the project and it was considered that the same plants may be set up in the existing ash dyke of NCTPS by reclamation of some portion of the Ash Dyke. TNEB is presently having about 1100 acres of land for ash dyke purposes. Due to improved dry fly ash collection, it is proposed to reclaim 500 acres of the above land for setting up of this proposed power plant. Section - 2 Page 1 of 4

19 In this connection Board has accorded approval vide per. B.P (FB) No.88 Dt for following: To changes the project site location for the establishment of Ennore SEZ project of 2 x 600 MW or 2 x 800 MW capacity from the proposed land in the Ennore Multi special Economic Zone of TIDCO to the near by primary Ash pond I of NCTPS Ash Dyke depending upon the feasibility. To reclaim the primary ash pond-i of NCTPS Ash dyke, extending about 500 acres, for setting up the 2 x 600 MW / 2 x 800 MW thermal power project and to suitably modify the existing ash dyke for the continued use of the balance portion for ash disposal. To approach GoTN for obtaining approval for setting up the 2 x 600 MW / 2 x 800 MW thermal power project in the new site. In accordance with the above, the prefeasibility report has been prepared for establishing a coal based power plant of 2 x 800 MW capacity in the reclaimed portion of ash dyke in NCTPS, under State Sector Restructuring of TNEB In the G.O Ms No 114 dated , Government of Tamil Nadu has accorded approval in principle for the re-organisation of TNEB by the establishment of a holding company, by the name TNEB Ltd and two subsidiary companies, namely Tamil Nadu Transmission Corporation Ltd (TANTRANSCO) and Tamil Nadu Generation and Distribution Corporation Ltd (TANGEDCO) with the stipulation that the aforementioned companies shall be fully owned by Government. The Govt. has also constituted a Steering Committee to finalise the transfer scheme for the re-organisation of Board under section 131 of the Electricity Act, Service Contract was placed to M/s Feedback Ventures Private Limited, Mumbai for Consultancy Service for restructuring of TNEB on In the G.O Ms No 38 dated , the Government of Tamil Nadu has permitted to register the Tamil Nadu Transmission Corporation Ltd (TANTRANSCO). TANTRANSCO has been incorporated on The Certificate of commencement of business has been obtained for the TANTRANSCO on and subsequently TANTRANSCO has been Section - 2 Page 2 of 4

20 inaugurated by the Honorable Chief Minister of Tamil Nadu on The orders for appointment of Board of Directors for the TANTRANSCO have been issued by GOTN on and Chairman, Managing Director, Director-Transmission Projects, Director-Finance have assumed office on Director-Operation was posted on and assumed office on In the G.OMs No 94 dated , the Government of Tamil Nadu have permitted to register the Tamil Nadu Generation and Distribution Corporation Ltd (TANGEDCO) and TNEB Ltd. TANGEDCO and TNEB Ltd have been incorporated on Certificates for commencement of Business have been obtained for TNEB Ltd. and TANGEDCO on and respectively. The order for appointment of Board of Directors for the above companies have been issued by Government of Tamil Nadu on and Chairman cum Managing Director, Director Projects, Director- Generation and Director Finance have assumed office on The draft transfer scheme has been prepared and submitted to Government of Tamil Nadu for approval. The MOP, Government of India have agreed for the continuance of TNEB as State Transmission Utility and Licensee under the provisions of the Electricity Act, 2003 upto M/s. TANGEDCO has engaged M/s. to prepare the Detailed Project Report for setting up of 2 x 800 MW Coal based Super Critical Thermal Power Project at Ash Dyke of NCTPS. This Detailed Project Report brings out the power plant philosophy, power plant requirement basis and salient features of major equipment, design consideration for civil & structural engineering works and data for main plant, equipment & BOP etc. The Report also gives cost estimates, based up on current day prices, financial analysis and tariff computations for Energy in line with Govt. of India Guidelines. Section - 2 Page 3 of 4

21 2.2.0 Scope of this Report a) Review of the planned generation capacity Vis-à-vis. power and energy requirement of Tamil Nadu State and establish the need for installation of the new thermal Power plant. b) Review of accessibility of plant site by rail and road, transport of coal & fuel oil required for the plant, estimation of quantity of water for condenser cooling / SG makeup, power evacuation plans and space availability for ash disposal. c) Preparation of plant layout, general arrangement drawings of steam turbine building, boiler area, coal storage & conveying system up to bunkers and ash handling system. d) Preparation of flow schemes of water system, coal and ash handling systems. e) Details of the major aspects of the proposed plant, general design philosophy and salient technical details of the following major equipment / systems for the proposed 2 x 800 MW capacity thermal power plant installation Main Plant consisting of Steam-generator and Steam turbine generator and auxiliary systems. Water systems. Coal handling systems. Ash handling system including ash disposal system. Other mechanical balance of plant systems. Electrical systems. Instrument and control systems. Environmental aspects of the proposed power plant. Preparation of project milestone schedule. Preparation of project cost estimate and cost of generation. Section - 2 Page 4 of 4

22 Section 3 Executive Summary The power generation in India started in the year 1897 by commissioning of 130 kw generator at Sidrapong in Darjeeling and second Power Plant of 1000 kw capacity was commissioned in the year 1899 by CESC. The Power generation in India was with the Private Sector during the Pre Independence period. The Post Independence period started with the formation of State Electricity Boards in early 50 s. The formation of the National Thermal Power Corporation and National Hydro Electric Corporation in the year 1975 generated the momentum for the significant growth in the power Industry in India. The total installed capacity in India as of end October 2010 is 1, 67, MW. In this the private sector contribution is MW (19.8%) of the total installed capacity. The installed capacities in the State and Central Sectors are MW (49.1%) and MW (31%) respectively. The energy demand during [ ] was 830,594 Million units [MU] and the supply was falling short by 10.1 % at 746,644 MU. In the peak demand situation is even more critical. There is a deficiency of 13.3 % as 104,009 MW is available for supply as against a demand of 119,166 MW. This deficit in power and energy in the country justifies the need for additional new power generation capacity. The availability of Indian / Imported Coal and the power demand encourages the installation of Power plants in Tamil Nadu State. The Power plant of 2 x 800 MW capacity will be able to bridge the gap of power deficit in the State of Tamil Nadu. TANGEDCO has planned to establish 2 x 800 MW coal based super critical thermal power plant in Vayalur village near Ennore port. TANGEDCO proposes to fire Indian / Imported coal, where Indian coal has sourced from kalinga block of the Talcher, Mahanadhi and IB valley coal field. The Imported coal has been sourced from foreign countries through sea to Ennore port. The coal will be conveyed from port through conveying system which is approximately 4.0 km from plant site. The present Pulverized Coal firing combustion technology is capable of firing the low grade, high ash coal. Section - 3 Page 1 of 14

23 The power plant process flow diagram is enclosed in Drawing no: CCE ME Steam Generating Units The steam generator will be sliding pressure supercritical, once-through type, utilizing a Tangential Firing System for NO X control, single reheat, variable pressure operation, with balanced draft furnace conditions. The unit is capable of firing the range of pulverized coals as a Main fuel. The steam generating unit for 800 MW will be sized for 2600 TPH steam flow at, 256 ata steam pressure and 568 C steam temperature, 595 C reheat temperature with at 100% MCR, Super heater outlet and re-heater outlet respectively with design consideration of firing Indian / Imported / Blended coal as main fuel. This will ensure adequate margin over the requirement of Turbine at 100% MCR to cater for auxiliary steam. The Steam generator will be designed to operate with "the HP Heaters out of service" condition (resulting in lower feed water temperature at Economizer inlet) and deliver steam to meet the Turbo generator requirement at 100% MCR. The steam generator will be suitable for operation with 60% capacity HP-LP Turbine bypass system envisaged for Turbo generator. The horizontal economizer section will be of non - steaming type with provision for recirculation during start-up, chemical cleaning etc. Superheater and Reheater sections will be horizontal / vertical, convection and radiation type and designed to maintain rated steam temperature of 568 C / 595 C at outlet of Super heater / Re-heater over the control range of 60% to 100% MCR load. A superheater desuperheating station with provision for spraying water, tapped off from feed water piping, will be provided. Reheat temperature control will be through the use of burner tilt or through damper control and through desuperheater in case of emergency Boiler Feed Pumps and drives 2 x 50% Turbo Driven Pump + 2 x 30% Motor Driven Boiler feed pumps are envisaged for each unit. Each Boiler Feed Pump will be Multistage Horizontally split type two-piece inner casing, Double volute structure, Opposed type impeller arrangement, with booster pumps. Section - 3 Page 2 of 14

24 3.1.3 Pulverizing Plant Ten (10) numbers (8W + 2S) of pulverizers with adequate capacity are envisaged. Hot primary fans and seal air fans of adequate capacity with necessary piping, local instruments, valves, suitable for remote operation from the control room etc are included with the sealing system designed so as to prevent any leakage of coal dust into the bearing and atmosphere. Apart from the pulverizers, boiler unit will be equipped with Ten (10) Nos. of coal feeders, Ten (10) nos. of gravimetric coal feeders; 2 X 50% of Axial reaction type primary air and forced air fans; and two of axial reaction type for Induced draft fans Seal air fans will be provided to seal air for the bearings, journals, feeders etc. as well as fuel and air piping Electrostatic Precipitator (ESP) Each steam generating unit shall be installed with Six (6) Electrostatic Precipitators with adequate fields in the direction of gas flow and two (2) bus sections perpendicular to the gas flow. All the fields of the precipitators are provided with approx. 400 mm electrode spacing considering with one (1) field out of service. The ESP will have a collection efficiency of around 99.99%. The outlet dust concentration from the chimney will be limited to 50 mg/nm 3 as per the latest regulation of Central Pollution Control Board. Each ESP will be provided with ash hoppers having capacity suitable for storing ash collected in at least one (1) shift operation of the Boiler at 100% MCR Steam Turbine The steam turbine of 800 MW, will be a horizontally split, multi cylinder (one HP, one IP & two LP) 3000 rpm multistage, tandem compound, single reheat, condensing type unit uncontrolled extractions for regenerative feed water heating. The turbine will be designed for main steam parameters of 247 ata, C/593 0 C at emergency stop valves of H.P. turbine / IP turbine. Section - 3 Page 3 of 14

25 High-Pressure Turbine (HP Turbine) The HP Turbine is a double shell casing with vertically guide blade carrier and axially split barrel type outer casing. Intermediate-Pressure Turbine (IP Turbine) The IP-turbine is of double flow. The double-shell casing consists of a horizontally split inner and outer casing. Low-Pressure Turbines (LP Turbine) Each LP-turbine consists of two double-flow units with a horizontally split casing. The LP turbine will exhaust against condenser pressure of about ata. The Turbo-generator set will be designed for a maximum throttle steam flow at Turbine Valve Wide Open (V.W.O.) condition of about 105% of Turbine MCR condition. The turbine will be rated for a minimum of 800 MW and shall be capable of both constant and variable pressure operations as well as with HP heater out Condensing Equipment Two (2) nos. of single/double pass surface condenser each unit having a different exhaust pressure of / ata will be provided at steam side respectively, and cooling water side of condensers in series with adequate hot well capacity capable of maintaining the required vacuum while condensing steam at the maximum rating of the turbine, will be provided for each unit. The condenser is of box type construction with divided water box design and is provided operation of one half of the condenser while the other half is under maintenance. The steam space will be rectangular cross-section. The condenser is provided with integral air cooling section from which air and non-condensable gases are drawn out with the help of air evacuation equipment. Tubes material will be titanium and tube sheet material will be carbon steel with titanium overlay as raw water is proposed to be used. Cathodic protection of condenser water box is envisaged. The condenser cooling will be through cooling tower in closed circuit system. Section - 3 Page 4 of 14

26 3.1.7 Deaerator and Feed Heater Each unit will be provided with a variable pressure Spray-cum Tray type Deaerating heater with a feed water tank with minimum 10 minutes effective capacity and initial heating facility. Deaerator will be designed to deaerate all the incoming condensate and drain flow to keep the oxygen content of the condensate below the permissible limit of 0.005cc/lt. Deaerator normally operate by taking extraction steam from turbine casing except during light load operation and start up. It will be pegged with steam drawn from the auxiliary steam header. Deaerator will be located at suitable elevation to provide sufficient Net Positive Suction Head (NPSH) for the boiler feed pumps Generator The Synchronous generators shall be totally enclosed, horizontal shaft driven directly by steam turbine at 3000 rpm. The generator shall be cylindrical rotor, continuously rated for the turbine outputs and rated at a minimum of 800 MW, 0.85 (lagging) power factor, delivering power at 27 kv, 3 phase, 50 Hz star connected, in IP-54 enclosure. The generators will be capable of operating in isolation or in parallel with the power grid, with voltage variations of ±5% and frequency variations of 47.5 to 51.5 Hertz. The generator will have Class-F insulation with temperature rise limited to class B limits and shall be hydrogen cooled Coal Handling System Coal Requirement & Transportation It is proposed to transport the imported coal from Indonesia / South Africa / Australia & other countries and Indian coal from kalinga block of the Talcher, Mahanadhi and IB valley coal field to Ennore port through ship and stored at the proposed coal berth III by TANGEDCO. Further coal can be conveyed through the closed conveyors to the proposed power plant. The required Indian coal for the proposed project can be sourced from Kalinga Block of Talcher coal fields, Mahanadhi and IB valley coal fields. Required imported coal for the proposed project can be sourced from Indonesia / South Africa / Australia or other countries. Section - 3 Page 5 of 14

27 The requirement of coal will be as follows: Description Option - I Option II Option - III Option - IV Type of Coal 100% Indian coal 100% Imported coal 70% Ind coal + 30% Imp coal 70% Imp coal + 30% Ind coal GCV in kcal / kg Fuel Consumption for Two (2) Nos. of Boiler in TPH Fuel Consumption per 100 % PLF in MTPA Fuel Consumption per 85 % PLF in MTPA The capacity of coal handling plant for design condition will be estimated as 2000 Tons Per Hour with two streams (1W + 1S) operating at 16 hrs/day considering 100% Indian Coal Ash Handling System The ash handling system is designed for 100 % of Indian coal considering 45 % of ash (worst condition) to meet the following parameters: Description Coal consumption at full load for 2 Units 100% Indian coal 1084 TPH Ash content in coal (worst condition) for design 45% Total ash produced from both the units Bottom Ash (15%) Fly Ash (85%) 488 TPH 74 TPH 414 TPH Bottom Ash The Bottom Ash Handling System is to extract, cool, grind and transport in a completely dry way, the hot bottom ash and the unburned carbon, which fall Section - 3 Page 6 of 14

28 down into furnace ash hopper up to bottom ash storage silo. The Bottom Ash Handling System comprises of the following equipment: In case of emergency bottom ash will be extracted through intermittently operating jet pump system, the jet pumps would convey the bottom ash slurry from water impounded bottom ash hopper to the slurry sump of the combined ash slurry disposal pump house Fly Ash System Fly ash collected in various APH, Induct, ESP and Stack hoppers shall be extracted and conveyed to intermediate surge hopper automatically and sequentially by means of vacuum generated by mechanical exhauster and shall be transported to fly ash silos by means of pressure conveying system. Pneumatic conveying system shall be employed for extraction of fly ash from the electrostatic precipitator hoppers in dry form. Fly ash removal shall be completed in 5.5 hours for every eight hours shift. Incase of emergency fly ash will be extracted in wet form Plant Water System Option I: (Sea Water + Metro water) The raw water requirement for the proposed power plant is estimated m 3 /hr considering the m 3 /hr of Sea Water from existing cooling tower forebay of NCTPS Stage II (cooling tower make-up) and 1030 m 3 /hr for metro water from Metro Water Supply & Sewerage Board (CMWSSB) for boiler make up & other sweet water requirements Option II: (Sea Water) The raw water requirement for the proposed power plant is estimated m 3 /hr and the same can be met from existing cooling tower forebay of NCTPS Stage II. The make-up water for cooling tower, boiler make up & other sweet water requirements are to be met from proposed desalination plant and Demineralized plant. The ~10 cumecs of excess water is available at the existing cooling water fore bay of NCTPS Stage II which is located at ~5 kms away from the proposed site. Section - 3 Page 7 of 14

29 Cooling Towers The circulating cooling water requirement for the proposed thermal power plant per unit is estimated m 3 /hr for condenser cooling and 6000 M 3 / hr for auxiliary equipments. The CW system envisaged for the plant is re-circulating type system with One (1) no of Natural Draft Cooling tower per unit using clarified sea water as a make-up water. The cooling towers will discharge the recooled circulating water to CW pump house circulating water sumps. Number of cooling towers : One (01) no for each unit Type of cooling tower : Natural Draft Design inlet circulating water flow rate : 92,000 m 3 /hr per unit Cooling range of circulating water : 10 0 C Ambient wet-bulb temperature : 27 0 C (for CT design) Circulating water makeup : Clarified sea water Suitable arrangement for shock & continuous dozing of chlorine to curb organic growth and chemical dozing i.e. scale / corrosion inhibitor and biocide dozing for maintaining 1.3 COC are made for sea water Cranes and Hoisting Equipment Two (2) nos. of 130/30T electrically operated overhead traveling type (EOT) crane is envisaged in the T.G. Hall. Crane to be provided will be designed and manufactured as per IS-3177/IS-807. The cranes will be double box girder, M3 duty, indoor duty Generator Step-Up Transformer The Generator transformer for each 800 MW unit is of Three Nos of single phase, 50HZ, 420/ 3 / 27/ 3 KV, YNd1, each 320/256/192 MVA, OFAF/ONAF/ONAN cooled oil immersed outdoor transformer. Generator transformer will be provided with OFF Circuit Tap Changer (OCTC) having tap change range of ±5% in steps of 2.5% on H side. Section - 3 Page 8 of 14

30 Unit Transformer (UT) Two (2) numbers of Unit transformers for each 800 MW unit are envisaged. Each Unit Transformer shall be of Three phase, 27kV/11.5 kv, 70 MVA, Dyn 11 ONAN cooled oil immersed outdoor type. Unit transformers will be provided with ON Load Tap Changer (OLTC) having tap change range of ±5% in steps of 2.5%. Transformers will be provided with requisite protection devices and accessories LT Auxiliary Transformer Required Nos. of 11 kv / 433 V adequately rated transformers for supplying the unit loads and station low voltage loads will be provided. The transformers are sized on the basis of 2 x 100% rating. These transformers will be provided with off circuit tap changer ± 5% in steps of 2.5%. The auxiliary transformers will be DYn11 connected and the neutral will be effectively grounded Switchgears KV Switchgear 11 kv switchgear will be metal clad vertical single front draw out type for indoor installation Volt Switchgear The 3.3 kv systems will be non-effectively earthed. The switchgear will be rated for a symmetrical fault current of 40 KA for 1 sec. The 3300 V switch gear will comprise draw-out type Vacuum/SF6 circuit breakers housed in indoor, metal-clad cubicles and will cater to all 3.3 kv motors Instrumentation and Controls Plant control & instrumentation provide a simple effective and fail-safe means for reliable and efficient operation of the plant under dynamic conditions and for attainment of maximum station availability. To achieve this objective, control and monitoring facilities are designed so that operation of the Boiler, Turbine, and Generator along with their major auxiliaries would be accomplished from a CCR (Central Control Room). From the CCR, operators would start-up, load, unload, release for remote dispatch, shutdown and monitor the steam generator, turbine and other auxiliaries of the plant. To fulfill the above functional requirements, a Distributed Digital Control and Management Information System (DDCMIS) with Section - 3 Page 9 of 14

31 TFT / Keyboard operation for SG and TG controls and hard-wired back-up controls with monitoring and controlling devices needed for operation is envisaged. All field instruments like transmitters for flow, pressure, level and differential pressure are of smart type with HART Protocol Project Information A. Technical Information 1. Land area for Power plant : 500 Acres 2. Water 2.1 Option I : Sea water from existing fore bay of NCTPS Stage II for cooling tower make-up. Water from Metro Water Supply & Sewerage Board for boiler cycle make-up and other utilities. a. Total raw water requirement : m 3 /hr 2.2 Option II : Sea Water a. Total raw water requirement : m 3 /hr 3. Cooling system : Closed circuit with an Natural Draft cooling tower 4. Primary Fuel : Imported / Indian /Blended 5. Support Fuel & Source : Heavy Furnace Oil (HFO) and Light Diesel Oil (LDO) from nearest depot / source. 6. Fuel consumption 6.1 Option I : 100% Indian coal a. Fuel Consumption Per Boiler : (542) TPH b. Fuel Consumption for Two (2) Nos. of Boiler : (1084) TPH c. Fuel Consumption per annum : : (9.495) Million tons at 100 % PLF load (8.071) Million tons at 85 % PLF load Section - 3 Page 10 of 14

32 6.2 Option - II : 100% Imported coal a. Fuel Consumption Per Boiler : (305.5) TPH b. Fuel Consumption for Two (2) Nos. of Boiler : (611) TPH c. Fuel Consumption per annum : : (5.352) Million tons at 100 % PLF load (4.549) Million tons at 85 % PLF load 6.3 Option - III : Blended (70% Indian coal & 30% Imported coal) a. Fuel Consumption Per Boiler : (440) TPH b. Fuel Consumption for Two (2) Nos. of Boiler : (880) TPH c. Fuel Consumption per annum : : (7.708) Million tons at 100 % PLF load (6.552) Million tons at 85 % PLF load 6.4 Option - IV : Blended (70% Imported coal & 30% Indian coal) a. Fuel Consumption Per Boiler : (351.5) TPH b. Fuel Consumption for Two (2) Nos. of Boiler : (703) TPH c. Fuel Consumption per annum : : (6.158) Million tons at 100 % PLF load (5.234) Million tons at 85 % PLF load 6.4 Coal storage days at site : 21 days 6.5 Support fuel required (HFO) per annum : KL 7. Ash Generation 7.1 % of Ash content in Indian coal : 45% (Worst Condition) 7.2 Ash generation for both units : (488) TPH 7.3 Total Ash generation per annum : (4.274) Million tonnes 7.4 Ash utilisation : 100% commercial applications. Section - 3 Page 11 of 14

33 8. Boiler & its Auxiliaries 8.1 Steam generator : Pulverized Coal (PC) Fired Boiler 8.2. Steam Parameters per Boiler : Flow 2600 TPH Pressure 256 ata Temperature 568 / 595 o C 9. Turbine & its Auxiliaries 9.1 Turbine : Horizontally split, multi cylinder throttle governing (one HP, one IP & two LP) 3000 rpm multistage, tandem compound, single reheat, condensing type unit uncontrolled extractions for regenerative feed heating, 800 MW 9.2 Electrical Generator : Two-pole, hydrogen-cooled turbo generator with direct water cooling for the stator winding, which is directly coupled to the turbines, a rotating-diode brushless excitation system, 50 Hz., 3000, 3 phase, 0.85 power factor (lagging), 27 KV. 9.3 Turbine heat rate : 1850 Kcal / kwh 10. Chimney 10.1 No. of Chimney : One (01) Twin flue 10.2 Height of Chimney : 275 meter high (RCC Structure) 11. Power Evacuation : Through 400 kv GIS to nearby substation 12. Project Schedule 12.1 Unit 1 : 48 Months 12.2 Unit 2 : 54 Months Section - 3 Page 12 of 14

34 13.0 Costing 13.1 Project cost without IDC : Rs Crores 13.2 Cost per MW without IDC : Rs Crores 13.3 Syndicate 0.4% & Upfront 0.1% 13.4 Total Project Cost without IDC including upfront fees & Bankers fees : Rs Crores : Rs Crores 13.5 IDC : Total project Cost with IDC : Rs Crores 13.7 Cost per MW with IDC : Rs.6.97 Crores 13.8 Moratorium Period : 6 Months 13.9 Cost of Generation : Condition I (Blended Fuel 70% Indian + 30% Imported) a. GCV of Blended Fuel : 3820 Kcal/kg b. Cost of fuel : Rs per ton c. Cost of 85% PLF : Rs per unit d. Levellised 85% PLF : Rs per unit Condition II (Blended Fuel - 30% Indian + 70% Imported) a. GCV of Blended Fuel : 4780 Kcal/kg b. Cost of fuel : Rs per ton c. Cost of 85% PLF : Rs per unit d. Levellised 85% PLF : Rs per unit Condition III (100% Indian Coal) a. GCV of Indian coal : 3100 Kcal/kg b. Cost of fuel : Rs per ton c. Cost of 85% PLF : Rs per unit d. Levellised 85% PLF : Rs per unit Section - 3 Page 13 of 14

35 Condition IV (100% Imported Coal) a. GCV of Imported Coal : 5500 Kcal/kg b. Cost of fuel : Rs per ton c. Cost of 85% PLF : Rs per unit d. Levellised 85% PLF : Rs per unit Conclusion of this Report Based on the details of load forecast and assessment of likely addition of new generation capacity it is anticipated that Tamil Nadu State would experience a power deficit of 32.7 % and energy deficit of 25.8 % in the year This deficit in power and energy justifies the need for additional new power generation capacity. Accordingly M/s. Tamil Nadu Generation and Distribution Co. Ltd plans to install a 2 x 800 MW coal based supercritical thermal power plant in Vayalur Village, Thiruvallur District, Tamil Nadu. The power plant of 2 x 800 MW capacity will be able to bridge the gap of power deficit. Section - 3 Page 14 of 14

36 Section 4 Need of the Project Power Need for Life Electricity is an essential requirement for all parts of our life. It has been recognized as a basic human need. It is a critical infrastructure on which the socioeconomic development of the country depends. Supply of electricity at reasonable rate to rural India is essential for its overall development. Equally important is availability of reliable and quality power at competitive rates to Indian industry to make it globally competitive and to enable it to exploit the tremendous potential of employment generation. Indian Power sector is witnessing major changes. Growth of Power Sector in India since its Independence has been noteworthy. However, the demand for power has been outstripping the growth of availability. Substantial peak and energy shortages prevail in the country National Electricity Policy The National Electricity Policy aims at achieving the following objectives: Access to Electricity - Available for all households in next five years Availability of Power - Demand to be fully met by Energy and peaking shortages to be overcome and adequate spinning reserve to be available. Supply of Reliable and Quality Power of specified standards in an efficient manner and at reasonable rates. Per capita availability of electricity to be increased to over 1000 units by Minimum lifeline consumption of 1 unit/household/day as a merit good by year Financial Turnaround and Commercial Viability of Electricity Sector. Section - 4 Page 1 of 12

37 4.3.0 Indian Power Scenario (as on ) Below furnished information s are extracted from Central Electricity Authority (CEA) Integrated Resource Planning Division Report Power Scenario Based on type of Fuel / Energy Fuel MW Percentage Coal 89, Gas 17, Oil 1, Total Thermal Hydro (Renewable) 37, Nuclear 4, Renewable Energy Sources 16, Total 1,67, Sector-wise Power Scenario Sector Hydro Thermal Coal Gas Diesel Total Nuclear R.E.S (MNRE) Total STATE PRIVATE CENTRAL TOTAL The power sector in India portrays a vibrant face with dynamic reforms. The power situation appears bright. The total installed capacity in India as of end October 2010 is MW. In this the private sector contribution is MW i.e. 19.8% of the total installed capacity. Thermal Energy route takes a lion s share with an installed capacity of MW [64.9%]. Further, coal based installed capacity is 89, MW [82.6%] of the thermal energy. Coal offers an economical and sustained power generation route in India. Section - 4 Page 2 of 12

38 Actual Power Supply Position Period Peak Demand (MW) Peak Met (MW) Peak Deficit / Surplus (%) Energy Requirement (MU) Energy Availability (MU) Energy Deficit / Surplus (%) End of 9th Plan APR-OCT, OCT, The energy requirement during was 830,594 Million units [MU] and the supply was falling short by 10.1 % i.e. at 747,534 MU. The peak demand situation is even more critical. There is a deficiency of 12.7 % as 104,009 MW is available for supply as against a demand of 119,166 MW. The challenges to be faced are growing purchase power of individuals and per capita power consumption, urbanization of towns, electrification of villages and rural areas. Village and rural electrification has always been a thrust area. Even now, the number of electrified villages is only 56.5%. The household s accessibility to power is 55% as per census Section - 4 Page 3 of 12

39 Power Scenario of Southern Region Installed Capacity at the End of 10th Plan MW Installed Capacity as on MW Peak Demand Deficit at % Energy Deficit at % Capacity Addition during 11th Plan (As Per Planning Commission Target) MW Power supply Position at the End of (Demand as per 17th EPS) Period Peak Demand (MW) Peak Met (MW) Peak Deficit/ Surplus (MW) Peak Deficit/ Surplus (%) Energy Requirement (MU) Energy Availability (MU) Energy Deficit/ Surplus (MU) Energy Deficit/ Surplus (%) Power Scenario of Tamil Nadu Installed Capacity at the End of 10th Plan MW Installed Capacity as on MW Peak Demand Deficit at % Energy Deficit at % Installed Capacity (at the end of 10 th Plan) (in MW) Sector Hydro Thermal Coal Gas Diesel Total Nuclear R.E.S (MNRE) Total STATE PRIVATE CENTRAL TOTAL Section - 4 Page 4 of 12

40 Installed Capacity as on (figures in MW) Sector Hydro Thermal Coal Gas Diesel Total Nuclear R.E.S (MNRE) Total STATE PRIVATE CENTRAL TOTAL Likely capacity addition during 11 th Plan Project Type Status Installed capacity (MW) Capacity addition during XI plan Benefits shares of state (MW) commissioned /slipped during (MW) Unit wise commissioning date/(likely date of commissioning CENTRAL-SECTOR NEYVELI II LIG T U SIMHADRI EXT U-3,4 VALLUR (ENNORE) JV T U T U KAIGA U-3 & 4 N U COMM KUDANKULAM U- 1& 2 KALPAKKAM (PFBR) N U N U CENTRAL-SECTOR TOTAL : STATE SECTOR BHAWANI BARRAGE II & III METTUR EXT. U- 1 VALUTHUR PH-II GT,ST NORTH CHENNAI EXT U-1,2 H U T U T C COMM 59.8 COMM T U STATE- SECTOR TOTAL : GRAND-TOTAL : NOTE: U - UNDER CONSTRUCTION PROJECTS; C COMMISSIONED Section - 4 Page 5 of 12

41 Power supply Position at the End of (Demand as per 17 th EPS) Period Peak Demand (MW) Peak Met (MW) Peak Deficit/ Surplus (MW) Peak Deficit/ Surplus (%) Energy Requirement (MU) Energy Availability (MU) Energy Deficit/ Surplus (MU) Energy Deficit/ Surplus (%) From the above table it is evident that Tamil Nadu State is having peak deficit in power supply. Contingency measures are being take-up to meet the shortfall to the extent possible. Power Grid Corporation of India Ltd has interconnected the Southern region grid with the other regions and it is now feasible to transmit power to any region in the country Mega Power Status The mega power policy was introduced in November 1995 for providing impetus to development of large size power projects in the country and derives benefit from economies of scale. In order to accelerate the rate of capacity additions in the power sector and lower the cost of power, the Central government announced the mega power project policy. Detailed guidelines under the policy were also notified. Under the mega power project policy, the government notified select projects in the public and private sector as mega power projects. Mega power projects are entitled to concessions and benefits, such as Exemption from Excise duty on imports of equipment and material Security of payment through the sale of power to power Trading Corporation (PTC), which in turn would have to sell power to beneficiary states. Refund of terminal excise duty paid by various supplier on supply of equipments and material. In order to qualify for the mega power status, projects would have to satisfy the following criteria: Capacity of 1000 MW in case of thermal projects (including coal and natural gas based projects) Sell power to more than one State. Section - 4 Page 6 of 12

42 Mega power projects in the public/private sector would have to be awarded through competitive bidding process only. In order to buy power from mega power projects, States had to fulfill the following criteria: Establish State Electricity Regulatory Commission Privatize distribution in cities with a population of over 1 million Modification to the Mega Power Policy: (Source PIB release dt ) The Mega Power Policy guide lines were modified in 1998 and 2002 and were last amended in April 2006 to encourage power development in Jammu & Kashmir and the North Eastern region. In order to rationalize the Mega Power Policy and bring it in consonance with the National Electricity Policy 2005 and tariff Policy 2006, The Union Cabinet on approved the following modifications in the existing mega power policy: The existing condition of privatization of distribution by power purchasing States would be replaced by the condition that power purchasing States shall undertake to carry out distribution reforms as laid down by the Ministry of Power. The conditions requiring inter-state sale of power for getting mega power status would be removed. The present dispensation of 15% price preference available to the domestic bidders in case of cost plus projects of PSUs would continue. However, the price preference will not apply to tariff based competitively bid projects of PSUs. A Committee would be set up under the planning Commission with DHI, MoP and DoR as members which would suggest options and modalities to take care of the advantages suffered by the domestic industry related to power sector keeping all factors in view. The benefits of Mega Power Policy will also be extended to Supercritical projects to be awarded through ICB with the mandatory condition of setting up indigenous manufacturing facility provided they meet the eligibility criteria. The requirement of undertaking international competitive bidding (ICB) by the developers for procurement of equipment for mega power projects would not be mandatory, if the requisite quantum of power has been awarded through tariff based competitive bidding. Section - 4 Page 7 of 12

43 A basic custom duty of 2.5% only would be applicable on brown field expansion of existing mega projects. All other benefits under mega power policy available to green field projects would also be available to expansion unit (s) (brown field projects) even if the total capacity of expansion unit(s) is less than the threshold qualifying capacity (1000 MW), provided the size of the unit (s) is not less than that provided in the earlier phase of the project granted mega power project certificate. All other conditions for grant of the mega power status shall remain the same. Mega Power Projects would be required to tie up power supply to the distribution companies/utilities through long term PPA (s) and may also sell power outside long term PPA(s) in accordance with the National Electricity Policy 2005 and Tariff Policy 2006, as amended from time to time of Government of India. The above modifications would encourage setting up of mega power plants to take advantage of economies of scale and improve their viability. It will simplify the procedure for grant of mega certificate and encourage capacity addition. It will also encourage technology transfer and indigenous manufacturing in the field of super critical power equipments Benefits of the Project Based on the plant model considered for the project, the following benefits may be derived off: After the installation of plant Facilities continuous, uninterrupted power will be supplied to the Grid. The implementation of the project would reduce overall expenditure to meet the energy requirement and power deficit in the State. The cost per thermal energy made available from the solid fuel is substantially low when compared with liquid fuels. CDM benefits CDM Benefits The Clean Development Mechanism (CDM), one of the flexible mechanisms under the Kyoto Protocol encourages development of Green house emission reduction projects in developing countries like India for achieving sustainable development and also earn carbon credits. The amount of carbon emission saved by such project Section - 4 Page 8 of 12

44 is required to be certified by the CDM executive board. The certificate specifying carbon reduction in tonnes can be sold to developed countries which are signatories to the protocol. One tonne of CO 2 reduced through CDM project in a developing country when certified by the CDM executive board becomes a tradable CER (certified emission reduction). Adopting Supercritical technology results in enhanced plant efficiency resulting in reduced coal consumption. The specific CO 2 emissions per MWh of generated electricity of a new supercritical coal fired power plant are lower than the emissions of the existing subcritical power plants operating in India. Thus the implementation of a new supercritical coal fired power project contributes to the overall reduction of greenhouse gas emissions making it eligible under CDM. The methodology for such projects has already been approved by the CDM Executive Board vide ACM Hence this project can generate tradable carbon credits under CDM thus improving the financial viability of the project Government / Statutory Approvals For setting up a Thermal power project a number of statutory and non-statutory clearances are required. The salient clearances are listed below: S. No Particulars Approval Authority 1. Land availability including forest Land Government of Tamil Nadu, and Ministry of Environment and Forest (MOEF). It is proposed to develop TANGEDCO land of about 500 acres from the existing Ash dyke area (~1100 acres) of NCTPS and there is no problem in acquisition of required land for the development of project. Section - 4 Page 9 of 12

45 S. No Particulars Approval Authority 2. Water requirements and its availability The water requirement for the proposed 2 x 800 MW super critical thermal power plant has been estimated as m 3 / hr considering Sea water & Metro water and m 3 / hr considering sea water alone. Supply of 4MGD water commitment received from CMWSSB (Copy Enclosed in Annexure 4.1). Department: Water Resources Department / Major Irrigation Department, Central Water Commission of Tamil Nadu 3. Coal availability & transportation TANGEDCO has planned to source the coal from kalinga block of Talcher-Mahanadhi and IB valley coal fields through Coal India Limited and also Imported coal from Indonesia / Australia / South Africa. Further coal can be transported (Indian coal & Imported coal) through sea to Ennore port and stored at coal berth 3 for TANGEDCO. 4. Pollution Control Clearance (water and Air) Central Pollution Control Board (CPCB) & State Pollution Control Board (SPCB) 5. Civil Aviation Clearance for Chimney Height 6. Rehabilitation & resettlement plan 7. Power absorption & evacuation plan National Airport Authority of India (AAI) Clearance for 275 M height chimney has been obtained vide AAI s letter ref no: AAI/SR/NOC/RHQ dated (Copy Enclosed in Annexure 4.2) There is no R & R issues Tamil Nadu Transmission corporation Ltd (TANTRANSCO) Section - 4 Page 10 of 12

46 S. No Particulars Approval Authority 8. Registration of company Registrar of company. 9. Environmental & Forest The requisite terms of Reference (TOR) for the EIA Clearance from MoEF / State Environment Dept. study has been obtained from MOEF/GOI vide communication dated On compliance of TOR conditions MOEF/GOI will be approached again for Environment Clearance. 10. Local Panchayat Union / Local Authority Municipality approval 11. Electrical Approvals Inspector of Electrical department 12. Boiler Approvals Inspector of Boiler and Factories 13. Ash Utilisation Plan 100% Dry ash disposal system is envisaged for the proposed new plants and fly ash is disposed of to the near by cement plants and In case of emergency it is proposed to utilize the existing ash dyke of NCTPS for bottom ash disposal. 14. Approval by State regulatory commission/central Regulatory Commission As per Electricity Act 2003, approval of SERC for tariff within the State and CERC for sale of electricity to more than one state will be obtained at appropriate stage Acknowledgment M/s. Cethar consulting Engineers Limited thankfully acknowledges the Co-operation and Support rendered by TANGEDCO for the preparation of this Detailed Project Report (DPR) Need & Justification of this Project Lack of availability of sufficient electric power has always been one of the greatest deterrents to the economic growth of the State. To mitigate the gap between demand and supply, TANGEDCO has proposed to study the feasibility of establishing of 2 X 800 MW Supercritical Coal based Thermal Power Plant in the existing ash dye of NCTPS. Section - 4 Page 11 of 12

47 The potential from Hydel plants is already exploited to the maximum. Further, the Hydel generation which is being restricted only to the monsoon period, could not cater to the overall power requirement of the region and hence the capacity addition in thermal power sector has become necessary. Many thermal stations presently in operation in Tamil Nadu are a decade or more old. Hence de-rating of the older station would result in reduction of power availability. Therefore, the total reliance on Hydel stations as base load power plant is not advisable. In such a situation implementation of base load power plants using thermal power generation is the preferred alternative. The actual growth in industrial, agricultural and domestic demand will establish that there is an appreciable shortfall in the installed capacity, demand and energy availability as on date. This shortfall will continue even after the commissioning of the proposed power plants in various parts of the State. As Tamil Nadu State is the most preferred State for industrialization, the industrial demand for power will be ever increasing. Added to the industrial demand the agriculture need as well as domestic consumption coupled with the improved standard of living of the population will be on the rise. Further, the grid is large enough to accommodate this proposed 2 x 800 MW coal fired supercritical power plant. Taking all these into consideration, establishment of the proposed supercritical power plant of 2 X 800 MW at Thiruvallur district is justified in all aspects, since this will only meet a part of the projected power demand. Section - 4 Page 12 of 12

48 Section 5 Site Selection Study Factors for Site Selection The following main factors have influenced the idea of setting up of the power plant during site selection: Availability of adequate vacant land for locating the power plant free from R & R Issues. Availability of adequate water for cooling water & make up requirements. Proximity of ports for transport of fuel Infrastructural facilities like road and rail for transportation. Adequate area for handling disposal of ash Proximity to near by marine terminal Suitability of soil characteristics for construction Details of Proposed Site and infrastructure Project Location The identified site is located about 35 kms northern side from city and located near the Ennore Multi Product Special Economic Zone proposed by TIDCO in Vayalur village in Thiruvallur District. The site is located between latitude, 13 degrees 17' to 13 degree 18' North and Longitude 80 degree 18'to 80 degree 19' East. It is flanked on the East by puzhudivakkam village, West by Neidavoyal village, North by TIDCO land and south by NCTPS secondary ash pond. The location Map of the Project is enclosed as Annexure Access To Site The site is approachable by road from Pattamanthri to NCTPS which is off Thiruvottiyur Ponneri High Road and by a Water Bound Macadam (WBM) road leading to NCTPS ash dyke. The nearest railway station is Athipattu Puthu Nagar at about 5 km. The nearest airport is at, which is about 60 km. The nearest sea port is Ennore which is about 5 km from the site. The existing WBM road leading to NCTPS ash dyke needs to be widened and strengthened for the transportation of heavy equipment and for project usage. In the existing ash Dyke road of NCTPS, a railway crossing subway which has to be digging out for Section - 5 Page 1 of 6

49 increasing the ground clearance for free movement of high roof vehicles. Otherwise TANGEDCO / Ennore Port Limited (EPL) jointly construct an over bridge / under bridge for Transportation of equipments to the proposed power plant Land Requirement & Availability The thermal power plant needs to accommodate a boiler house, power house, fuel handling plant including fuel storage area, ash handling plant including ash disposal area, water treatment plant including storage system, cooling water systems of a cooling tower including cooling water & auxiliary cooling water pump house, raw water intake system including pump house, switch yard, transformer yard, transmission corridor within plant, compressor house, turbine oil pump house, stack etc. The break up for land requirement is given below: S. No Details Area in Acres 01. Main Plant Area Water system area including cooling towers, raw water & fire Water 03 Misc. buildings & ware house area Vacant land for FGD plant Coal stock yard area Green belt Roads, drains and other Internal Corridor for cooling water and coal conveyor 09. Switch yard 50 Total Main Plant area (acres) Presently about 1100 acres of TANGEDCO s land are being used for ash dyke in NCTPS. It is suggested that some portion of the ash dyke area of about 500 acres is proposed to be reclaimed and beneficially utilised for establishment of the proposed 2 x 800 MW coal based supercritical thermal power plant. The rest of the ash dyke is sufficient to meet out the requirement of ash disposal of Section - 5 Page 2 of 6

50 NCTPS stage I & II as well as the proposed plant with modification / improvement works. The identified land for the power plant is free from Resettlement & rehabilitation issues. However, a detailed topographic survey and soil investigation will have to be carried out before taking up regular construction work Water requirement & availability Option I: (Sea Water + Metro water) The raw water requirement for the proposed power plant is estimated m 3 /hr considering the m 3 /hr of Sea Water from existing cooling tower forebay of NCTPS Stage II (cooling tower make-up) and 1030 m 3 /hr for metro water from Metro Water Supply & Sewerage Board (CMWSSB) for boiler make up & other sweet water requirements Option II: (Sea Water) The raw water requirement for the proposed power plant is estimated m 3 /hr and the same can be met from existing cooling tower forebay of NCTPS Stage II. The make-up water for cooling tower, boiler make up & other sweet water requirements are to be met from proposed desalination plant and Demineralized plant. Raw Water Analysis is attached in Annexure Advantages of selection of Sea water based RO plant for Proposed Power Plant Water requirement: CMWSSB has assured that they will be able to supply 4 MGD of water to the proposed power plant of 2 X 800 MW and the present cost of water is around Rs. 60 per m 3. A Copy of letter received from CMWSSB is enclosed as Annexure 4.1. CMWSSB water cost may increase year on year and also the avail. CMWSSB water over period of time may depend on many factors as it is an external source. CMWSSB water thus obtaining needs further treatment for producing process water (DM water) and cost of DM water will about Rs.150 cu m. Section - 5 Page 3 of 6

51 Any interruption of water supply from CMWSSB would affect the power plant operation. Considering all the factors, in order to have better raw water security, we propose to have a dedicated desalination plant (RO based) with sea water as the main source of feed. Approximately 10 cumecs of excess water is available at the existing cooling water forebay of NCTPS Stage II which is located at ~5 kms away from the proposed site. The RO plant with clarifier system shall be provided for treating sea water and the clarified water would be stored in clarified water storage tank and then treated in the DM plant and DM water is stored in DM water storage tank. The stored DM water should be used for the process requirement of proposed power plant. Also the cost of DM water from the dedicated Sea water membrane based RO / DM plant will be cost about Rs. 95 per m 3 which is less than the cost of treated CMWSSB water. The advantages: Continuous availability / operation round the year. For the RO plant feed water generally does not require heating so the thermal impact of discharge is lower. RO plant usually have lower energy requirement. RO plant has higher recovering water about 45-50% of sea water. RO process can remove unwanted contaminants such as tri halo methane precursors, pesticides and bacteria. RO plant take up less surface area than any other desalination technology for the same amount of water production Possibilities of using sewerage water as Raw Water: Due to Stringent water Chemistry to be maintained in Supercritical boilers the possibilities of using treated sewerage water for cycle makeup is not advisable. Even though the cost of obtaining sewerage water is very minimum but the initial cost and operational cost is high when compared to other options, for obtaining required water quality. Hence, this option is not considered Cooling water Requirement The cooling water requirement for the proposed thermal power plant is estimated to m 3 /hr per unit. It can be met from the existing cooling water fore bay Section - 5 Page 4 of 6

52 of NCTPS Stage II which is located 5 kms away from the proposed site. The excess water available at the cooling water fore bay will be ~10 cumecs, which will be sufficient for cooling water requirement. Raw water would be conveyed through the underground conduits to the plant site. Closed circuit re-circulation type of cooling system using clarified water as make-up with Natural draft cooling towers has been proposed for power plant Fuel Requirement & transportation Fuel Requirement The total Fuel requirement for 2 x 800 MW at 100% BMCR has been estimated as considering Indian / Imported / blended as mentioned below: Description Option - I Option II Option - III Option - IV Type of Coal 100% Indian coal 100% Imported coal 70% Ind coal + 30% Imp coal 70% Imp coal + 30% Ind coal GCV in kcal / kg Fuel Consumption for Two (2) Nos. of Boiler in TPH Fuel Consumption per 100 % PLF in MTPA Fuel Consumption per 85 % PLF in MTPA Fuel Transportation Indian Coal: TANGEDCO has planned to source coal from Kalinga block of Talcher - Mahanadhi and IB valley coal fields through sea up to Ennore port and stored at coal berth 3 for TANGEDCO and transported through closed conveyor to the proposed site which is approximately 04 kms. Imported coal: TANGEDCO has planned to source coal from foreign countries like South Africa / Australia / Indonesia through sea to Ennore port and stored at coal berth 3 for Section - 5 Page 5 of 6

53 TANGEDCO and transported through closed conveyor to the proposed site which is approximately 04 kms. Fuel Analysis (typical) is attached in Annexure Secondary Fuel Heavy Furnace Oil (HFO) will be sourced from IOCL/CPCL Terminal at Manali / nearest source, which is used as support fuel. The requirement of support fuel is estimated KL per annum Power Evacuation: Three sets of double circuit, 400 kv transmission lines proposed for the interconnection from power station switchyard up to the following 400 kv SS available in and around the project site for evacuation of about 1600 MW power from the proposed generating power plant. Sunguvar chattram Alamathy North TPS Stage II Thiruvalam Vallur TPS Sriperumpudur One 400 kv GIS switchyard will be constructed in the proposed power plant for evacuation of power through above transmission lines Environmental Considerations The proposed site is basically waste land devoid of habitation or population. No reserve forest or important historic place is situated in the near vicinity. Sea water / metro water will be used in closed circuit for circulating water system and the waste water can be discharged after proper treatment. Super Critical boilers will be adopted along with ESP to limit emission level. Modern technology will be adopted for transportation of coal. As such, no undue problem of installation of the power station at said location from environmental aspect is envisaged. Section - 5 Page 6 of 6

54 Section 6 Selection of Technology for Main Plant Equipment Technology Selection Higher capacity units came into operation in many countries at the end of last century unit capacities have increased to 1300 MW. However in India, except for a few units, the vast majority of the units were of 30 to 60 MW size till the seventies, India have quite a few 500 MW units in successful operation from eighties onwards. Still higher size unit like 660 MW units, are in the pipe line and are yet to be commissioned. Now entrepreneurs have proposed to manufacture large unit size of 800 MW to 1000 MW as the next size in the country with Super Critical Technology to increase the pace of capacity addition. The coal fired thermal power plants in India generally adopt sub critical technology for generation of power. The overall thermal efficiency of a conventional/sub-critical (operating steam pressure/temp at 130 Kg/sq.cm, 540 º C) coal fired thermal power plants depends on the combustion technology, operating conditions and coal properties. Sub Critical Boilers (500 MW sets) involves steam pressure of 170 bar and super heat / reheat temperature 540 C / 540 C and super critical boilers would be designed with pressure of 247 ATA and above, super heat/reheat temperature of 565 º C/592 º C and above. Also Improved heat rate with supercritical pressure steam with variable pressure operation which provides higher plant efficiency overall loads compared to sub critical pressure plants. Main focus about super critical boiler is on minimizing CO 2 emission originating from the fossil fired plants. CO 2 increase is linked to Global warming. Hence it offers advantage of Burn less fuel for the same output thus economical use of energy resources and low emission. Above an operating pressure of 225Kg/sq.cm, temperature 560ºC, once through (drumless type) cycle is supercritical wherein the medium is a single phase fluid with homogeneous properties and there is no need to separate steam from water in a drum. Adoption of once through boiler technology has advantage of operational flexibility to respond quickly to load changes and grid fluctuations, siding pressure operation and shorter start-up times. Section - 6 Page 1 of 21

55 6.2.0 Selection of Steam Generator Steam generators selection is done considering the following aspects: Generating station is base load. If at all load fluctuations comes, then the SG will respond fast. SG technology should be well proven in the Indian scenario. SG Operatibility, Maintainability and Efficiency should be among the best in the business. Based on the above, the only technology proven in India for unit capacities in the range of 500 MW and above by use of Pulverized Fuel Fired Boilers. With the Indian coals having ash content of the order of about 50% both single pass and double pass boilers are in successful operation. Consequently, the choice between the two will be determined on techno-economic basis. The scheme will be developed on the basis of drumless type boilers. The main advantages of the Pulverized Fuel Firing System are: 1) Less excess air is required for complete combustion because of greater surface area of fuel exposed. 2) Higher combustion air temperatures ensure higher cycle efficiency. 3) A good range of coal right from anthracite to peat can be successfully burnt. 4) Better combustion control enables the system to respond quickly to extensive load variation. 5) Slagging and clinkering problems are low. 6) Carry over of unburnt fuel to ash is practically nil. 7) Ash handling problem low. 8) Can operate successfully in combination with gas and oil fired systems. 9) Cold-start up of boilers is very rapid and efficient. 10) Less furnace volume is required Steam Generator - Pulverized Fuel Fired Boilers The PF boilers are based on firing of pulverized coal in the boiler furnace. Over the years, the technology has been upgraded and now boilers of capacity up to 1300 MW are available. The pulverized fuel boilers can be single pass or double pass depending upon the configuration of furnace and gas path. Section - 6 Page 2 of 21

56 Further, PF fired boilers can be drum type (sub-super critical pressure/ temperature conditions) or drum less type (super critical pressure and temperature conditions). Super critical boiler essentially differs from the sub super critical pressure conditions in that there is no boiler drum and the water in the boiler tubes directly convert into steam at super critical pressure and temperature condition. During combustion oxides of carbon, nitrogen and sulphur are produced normally. Oxides of carbon are allowed to escape to atmosphere. Oxides of nitrogen which are environmentally unfriendly are now limited to permissible values by selection of suitable coal burners and/or treating the flue gases to contain NO X emissions within permissible values. Oxides of sulphur are controlled by disbursing the flue gasses at a height such that ground level concentration is limited to acceptable values. This is possible because Indian coals have low sulphur content. The sulphur present in the coal is entrapped in Flue Gas Desulphurising (FGD) plant Introduction of Supercritical Technology "Supercritical" is a thermodynamic expression describing the state of a substance where there is no clear distinction between the liquid and the gaseous phase (i.e. it behaves as a homogenous fluid). Water reaches this state at a pressure above 225 bar. The requirements for environmental protection and operating economy in future steam power plants make high efficiency levels and operating flexibility a matter of course, but also in increasing measure around the world. Existing technologies have currently enabled fulfillment of these requirements by pulverized-coal-fired power plants and in part also by power plants with circulating fluidized bed (CFB) combustion systems. Higher efficiencies can be achieved only along the path of higher steam temperatures and pressures. Power plants operating at supercritical pressure and high steam temperatures were already being constructed in the 1950s. The 1960s saw a series of supercritical plants in the U.S. and in the last twenty years supercritical plants were used exclusively in Germany and Japan. The latter were designed for sliding-pressure operation and thus also fulfill the requirements for high operating flexibility and high plant efficiencies at part load. To date, CFB power Section - 6 Page 3 of 21

57 plants have been used especially for smaller power output levels, generally with drum boilers. Supercritical plants for ratings above 660 MW are planned in India. The transition to steam temperatures of 600 C and higher is now a further major development step, which decisively affects many aspects of the design of the power plant, especially of the boiler. Whether the transition to these high steam temperatures is economical also depends not only on the choice of main steam pressure, reheat pressure and feed water temperature, but also on the range of fuel Effect on Supercritical Technology design Size of heat exchange surfaces Higher steam temperatures automatically diminish the temperature differences between the flue gas and steam, with relatively large superheater and reheater heating surfaces as a consequence. As higher tube wall temperatures also mean an increased tendency to fouling, corresponding heating surface reserves must be provided. Feed water temperature has a large effect on the size of the heating surfaces in the cooler flue-gas path. Values of 290 C to 300 C or higher are necessary for high-efficiency plants. As on the one hand the flue-gas temperature downstream of the economizer is set in the design case at roughly 400 C the temperature window for DeNOx and on the other hand the water outlet temperature from the economizer is limited to avoid steaming, the upstream superheaters must absorb more heat with increasing feed water temperature. At higher steam conditions, especially at increasing reheat pressures, the exhaust steam temperatures from the HP section of the turbine and thus the reheat inlet temperatures also increase. While these temperatures are still approx. 320 C at a design main steam temperature of 540 C, they already increase to over 350 C in a 600 C main steam temperature design and even up to over 420 C in a 700 C design. This considerably decreases the temperature difference to the flue gas, with the consequence of still larger heating surfaces in the reheaters. Under consideration of a cost-effective heating surface design, feed water temperatures should not exceed 300 C, and HP exhaust steam pressures should lie in the range of 60 bar. Section - 6 Page 4 of 21

58 6.5.2 End of evaporation The location of the separator determines the location of the end of the evaporator on startup and at low load in recirculation mode. Usually the separator is configured such that its temperature is slightly superheated at the lowest once-through load point. Design of the boiler for high steam temperatures and pressures leads to this being already the case in lower areas of the furnace walls instead of as from the outlet first pass or in the boiler roof. The reason for this is the increasing degree of superheat and correspondingly decreasing fraction of evaporation in the heat input to the HP section with increasing steam parameters. At a load of 40%, the degree of superheat in a 540 C boiler is approx. 27%, and this increases to 39%, for example, in a design for 700 C main steam temperature as shown in below figure. As the highly loaded heating surface area must lie upstream of the separators for reasons of evaporator cooling and the separator thus cannot be moved arbitrarily toward the burners, a significantly larger degree of superheat will result at the lowest once-through operating point. This considerably increases the downward step of the steam temperatures on the transition to recirculation mode. In order to extensively prevent this temperature change, the transition from once-through to recirculation mode must be placed at a very low load point, requiring recirculation mode only for startup. Whereas for boilers with spiral wound tubing the minimum load in once through operation is in the range of 30% to 40%, an evaporator based on the design with vertical rifled tubes enables loads to below 20%. Section - 6 Page 5 of 21

59 6.5.3 Water Walls The water walls in boilers for subcritical steam conditions are generally configured as evaporators. At increasing steam temperatures and pressures, the fraction of evaporator heating surfaces decreases, with the result that parts of the water walls must also be configured as superheaters, i.e. downstream of the separator. In the highly loaded furnace area, spiral-wound evaporator tubing is usually used with smooth tubes and high mass fluxes approx kg/m³s. As spiralwound furnace tubing of this type is not self-supporting, it is reinforced with support straps which are welded to the tube wall with support blocks. High steam parameters also lead to higher material loading in the evaporator. The previously existing design reserves are no longer available, with the result that a detailed stress analysis is required for the design of the evaporator tubing in each case. As a result of the requisite large wall thicknesses, the design of highly loaded heating surface areas is in part no longer determined by the primary stresses due to internal pressure but rather by the secondary stresses due to re strained thermal expansion. The higher evaporator temperatures also result in increasing temperature differences between the tubes and support straps on startup and shutdown. This in turn leads to longer startup times, especially on cold start. The Low Mass Flux" designed with approx kg/m²s and below and with vertical rifled evaporator tubes requires no additional support structure and thus also does not impair plant flexibility in spite of wall outlet temperatures of approx. Section - 6 Page 6 of 21

60 500 C and above. In a design for main steam temperatures of 600 C and above, the creep strengths of the wall materials commonly used to date such as 13CrMo44 (T12) are no longer sufficient, necessitating the transition to new developments such as 7CrMoVTiB1010 (T24) or HCM2S (T23). This is already the case at steam pressures of 300 bar and above for lower design temperatures. Looking at primary stresses the creep strengths of these materials, which require no post-welding heat treatment, permit steam temperatures up to 530 C in the furnace walls depending on main steam pressure, but the corrosion resistance and secondary stresses limit these values down to 500 C. Main steam temperatures of 630 C at moderate steam pressures are thus achievable as regards the walls. At higher steam temperatures, materials such as HCM12 or T92 are required which must be heat treated after welding. In order to minimize the manufacturing expenditure in such a design, the erection welds on evaporator tubes must be reduced to the absolute minimum possible. This is currently feasible only with vertical tubing. The relatively complex welds in the corners for spiral wound furnace tubing are eliminated and the individual wall segments are welded together only at the fins. Welding of tubes may become necessary only in the horizontal plane. Solutions are also available for this which minimizes expenditure on heat treatment on erection. In all cases, it can be stated that the problems in the design of the water walls increase disproportionately with increasing steam pressures. A reduction of main steam pressure from 350 bar to 250 bar reduces the efficiency of a 700 C plant by 0.7 percentage points but it also reduces the wall outlet temperature from 540 C to 500 C and makes a design with materials without post weld heat treatment possible. Main steam pressures far above 250 bar should therefore be avoided, also in plants with high steam temperatures. Section - 6 Page 7 of 21

61 6.5.4 Evaporator/superheater dividing point At high steam parameters the water walls can no longer be designed entirely as an evaporator. The transition from evaporator walls to superheater walls then lies above the furnace. This transition must be designed so as to minimize the temperature differences between the evaporator and superheater sections of the walls which automatically result on water filling after shutdown, especially on water filling after an emergency shut down. Values of up to 80 K represent no cause for concern. For higher values such as can occur at very high steam conditions as well as in large furnaces, a flexible connection, not necessarily welded gas-tight, should also be taken into consideration for this transition Superheater heating surfaces For steam temperatures up to approx. 550 C, all heating surfaces can be constructed of ferritic or martensitic materials, while at 600 C austenitic materials are necessary for the final superheater heating surfaces for both the HP section of the boiler as well as the re-heater. In addition to the strength parameters, corrosion behavior on the flue-gas and oxidation behavior on the steam sides is especially determinative for material selection. Superheater materials for high temperatures, shows a selection of available materials. With regard to strength parameters, construction of superheater heating surfaces for steam temperatures up to 650 C is currently already feasible with austenitic steel materials. The corrosion resistance of the available materials however reduces the design limits to about 630 C. Proven in India Under development by Indian Manufacturer Under development by World Manufacturer Section - 6 Page 8 of 21

62 6.5.6 Effect on operation Power plants which are designed for fast load changes and short and frequent starts must necessarily be operated in sliding-pressure mode. Only then does the material loading of the turbine remain acceptable: in sliding-pressure operation usually between full load and 40% load - the temperature curve in the turbine remains nearly constant over the entire load range. These advantages for the turbine contrast with disadvantages for the boiler. For example, the temperatures in the water walls decrease from full load to part load by approx. 100 K. Due to their magnitude and the ordinarily larger wall thicknesses at the elevated steam parameters, the temperature changes during start up and load variations place increased requirements on the design of the thick-walled components such as multiple parallel passes, but also on the design of the tube walls, such as vertical tubing, in order to achieve similar startup times and load change rates to those in plants with conventional steam parameters. With increasing steam parameters, the degree of superheat at the outlet of the evaporator sections of the water walls at the lowest once-through load point also increases. A high degree of superheat in recirculation mode. The separators are therefore moved as far as possible toward the burner zone Operating measures to reduce the degree of superheat are increased excess air, flue-gas recirculation and use of the uppermost burner levels. The higher the steam temperatures and pressures are the more important in once-through operation, so that the oncethrough/recirculation mode transition need be traversed only on startup. The large degree of superheat in the separator at the lowest once-through operating point also results in changes in startup behavior at high steam parameters. On warm and hot startup in recirculation mode, the achievable hot steam temperatures are below the values required by the turbine. The earliest possible transition to once-through operation is necessary in order to shorten startup time, as full main steam temperatures are also already possible at low load in this operating mode. High feed water temperatures can restrict the sliding-pressure range in plants with very high main steam pressures. In order to prevent the economizer from approaching the evaporation point at low load, the pressure must be fixed below 50% load or still higher depending on the design. Increasing steam parameters also decrease the design reserves of nearly all pressure part components, as, not least for reasons of cost, the decision for advanced materials is not made until the Section - 6 Page 9 of 21

63 reserves of lower quality materials become insufficient. This also increases the requirements on control quality: temperature deviations from the design value, such as on load changes, must be kept to a minimum. The conventional cascade controller is no longer sufficient for superheat temperature control; concepts such as two-loop feedback control or observer features provide significantly better control quality. Special attention must be given to feed water control. Conventional systems which employ only simple delay modules to account for the dynamic differences between heat release by the fuel and heat absorption by the evaporator tubes usually lead to large temperature fluctuations at the evaporator outlet on load changes. New control concepts which account for effects such as those of changes in the evaporator inlet temperature or the thermal storage capacity of the tube wall in the form feed forward control (refer below diagram) increase control quality decisively and thus minimize the use of more expensive, higher-quality materials. For high degrees of superheat at the lowest once-through load point, the transition from recirculation mode to once-through operation and back can no longer take place without delay due to the relatively large temperature change; the control must be adapted accordingly for a sliding transition. Section - 6 Page 10 of 21

64 6.5.7 Other Effects Design of the tube walls in particular is impeded by the high steam temperatures and pressures. The design parameters should be selected as best as possible so as not to necessitate the use of materials for which heat treatment must be performed after welding. A significant aspect for this is selection of the fuel. Coals with low ash deformation temperatures require large furnaces, associated with high heat input to the walls. A 100K lower ash deformation temperature leads in a comparable boiler concept to a temperature increase at the wall outlet of about 25K. Because of this for the currently available wall materials without post-welding heat treatment, the ash deformation temperature for a 600 C boiler may not be much lower than 1200 C. (refer below diagram) The implementation of flue-gas recirculation extraction of the flue gases if possible upstream of the air heater in order to reduce the negative effect on exhaust-gas temperature can shift the limits to higher steam parameters. Steam generators for power plants with high steam parameters and hence high plant efficiencies are consequently also designed for high boiler efficiencies. The lowest possible exhaust-gas temperatures 115 C to 110 C can be achieved depending on the coal and lower excess air are prerequisites for this. Both of these factors lead to an increased heat input to the evaporator and thus impede the design of the wall heating surfaces Section - 6 Page 11 of 21

65 6.6.0 Spiral Wound Universal Pressure (SWUP) Boiler Design features A once-through boiler for supercritical applications, usually applied to systems with a capacity of 400 MW or larger; the design features a water-cooled dry-bottom furnace, superheater, reheater, economizer, and air heater components designed for both base load and full boiler variable pressure load cycling operation as well as on/off cycling operation Capacity, steam output From 252 kg/ s (2,000,000 lb/h) to more than 1260 kg/s (10,000,000 lb/h) Operating pressure Usually at 24.1 MPa (3500 psi) throttle pressure with 5% overpressure; higher pressures available Superheater steam temperatures: As required, currently in the 595 C (1100 F) range. Section - 6 Page 12 of 21

66 6.7.0 Vertical Tube Universal Pressure (VTUP) Boiler Design features A once-through boiler for supercritical applications, usually applied to systems with a capacity of 400 MW or larger; the design features a water-cooled dry-bottom furnace, superheater, reheater, economizer, and air heater components designed for both base load and full boiler variable pressure load cycling operation as well as on / off cycling operation Capacity, steam output From 252 kg/s (2,000,000 lb/h) to more than 1260 kg/s (10,000,000 lb/h) Operating pressure Usually at 24.1 MPa (3500 psi) throttle pressure with 5% overpressure; higher pressures available Superheater steam temperatures As required, currently in the 595 C (1100 F) range. Section - 6 Page 13 of 21

67 6.8.0 Advantages of Supercritical technology over subcritical technology The water-steam cycle is sub-critical up to an operating pressure of around 190 bar in the evaporator part of the boiler. This means, that there is a non homogeneous mixture of water and steam in the evaporator part of the boiler. In this case a drum-type boiler is used because the steam needs to be separated from water in the drum before it is superheated and led into the turbine. Above an operating pressure of 221 bar, the cycle is supercritical. The cycle medium is a single phase fluid with homogeneous properties and there is no need to separate steam from water in a drum. Once-through boilers are therefore used in supercritical cycles. The proposed project employs two supercritical coal fired power generation units, each having 800 MW gross capacity, providing a total capacity of 1600 MW. Supercritical technology, which is first-of-its kind in India, enables Rankine cycle to be operated at higher operating pressures thereby increasing the cycle efficiency. Higher efficiency means a reduction in fuel consumption and thereby a reduction in emissions per unit of electricity generated. The supercritical technology will enhance operational efficiency over sub-critical technology, which is the most prevalent and commonly used for thermal power generation in India. Comparison of Super Critical Boiler Vs Sub Critical Boiler S. No Parameter Sub Critical Boiler Super Critical Boiler Advantage over Sub Critical Boiler 1 Efficiency At 170 bar and 540/540º C (SH/RH) the efficiency will be 38% At 250 bar and 600/615º C or 568/595º C the efficiency will be 42% In Ultra critical units at 300 bar and 615/630º C the efficiency will be 44% Increase in efficiency directly leads to reduction in unit cost of power and CO2 emission 2 Operational Flexibility - Once through Technology - which is ideal for Sliding pressure operations The Sliding pressure operations has mush more advantages like: 1. Higher reheat steam temperature at part loads, Section - 6 Page 14 of 21

68 Comparison of Super Critical Boiler Vs Sub Critical Boiler S. No Parameter Sub Critical Boiler Super Critical Boiler Advantage over Sub Critical Boiler 2. High pressure turbine internal efficiency at part loads is high, 3. Faster step increase in load when loading rates are limited by the material stresses in turbine, 4. Shorter start up line, 5. Generator operational flexibility at part loads, 6. Lesser boiler feed water pumping power at part loads. 3 Evaporation End point 4 % of Super Heat Fixed Evaporation End points so furnace water walls act on the End point Evaporation End point can occur in various levels of furnace depending on boiler load Low High Furnace tubes act - more as super heaters than water walls. 5 Heat transfer area Low High - 6 Water Chemistry High purity required Extremely high purity required - 7 Material - Special high grade material for Boiler tubes. - Turbine blades are also of improved design and materials. Section - 6 Page 15 of 21

69 6.9.0 Conclusion Supercritical boiler technology has matured, through advancements in design and materials. Although earlier installed units in India had experienced various operation and maintenance problems in subcritical units. The coal-fired supercritical units supplied around the world over the past several years have been operating with high efficiency performance and high availability. Hence adopting super critical technology for higher size of coal based unit s leads to enhanced plant efficiency, less fuel consumption and reduced green house emissions. Adopting supercritical technology has the following advantages: Superior technology Reduced green house emissions Environmental friendly / CDM benefits Operational flexibility to grid fluctuations Shorter start-up times Reduced coal consumption Savings in coal cost Reduced O&M cost Improved ash management Considering on the various parametric conditions pressure & temperature of supercritical boiler is 256 ata and 568 C / 595 C are envisaged. However, other parameters are not yet proven in India as indicated in Also the auxiliary consumption and the capital cost of equipment, this steam parameters is the most preferred parameter Selection Technology for Steam Turbine Steam turbine is a prime mover which converts the thermal energy in the form of high pressure and temperature steam into mechanical energy. Mechanical energy will be converted into electrical energy in the Generator. Depending on the arrangement of nozzles and blades, Steam Turbines are classified into three main categories depending on the expansion of steam which are given below. Section - 6 Page 16 of 21

70 Impulse Turbines Reaction Turbines Impulse - Reaction Turbines In Impulse Turbines, the steam expands only in Nozzles and the blades will be only for producing torque to rotate the wheel. In subsequent developments in the steam turbine technology, the steam is allowed to expand in blades apart from producing the torque. Turbine having this type of arrangement is termed as Reaction Turbine. Steam turbine having the combination of both the arrangements is termed as Impulse-Reaction turbines. Turbines being manufactured presently are either impulse type or impulse reaction type. One set of Nozzles and Blades is termed as a stage. A steam turbine can be single stage type or multi stage type. In multi stage turbines, number of stages, each constituting nozzles and blades, are arranged in series. Hence, the expansion takes place successively, stage after stage. Blades of each stage are mounted on individual wheels which further mounted on common rotating shaft. Torque produced in each stage is compounded in a single rotating member. Steam after expansion passes out into the steam condenser or will be used for process requirements of the plant. Steam expansion takes place to the maximum extent in nozzles of Impulse Turbines when compared to the expansion in blades in Reaction Turbines. Hence, for a given pressure drop, impulse turbine requires less number of stages and reaction turbine requires more number of stages. Depending on the application and capacity of the power plant, either Impulse turbine or reaction turbine is used. For medium capacity power plants, Impulse reactions turbines are preferred due to simplicity in construction and less number of stages Supercritical Steam Turbines Unlike the boiler plant the design of the turbine plant is little affected by the use of supercritical pressure. Of course the high pressure cylinder must be designed to withstand the higher pressure and temperature and also the reheater pressure and temperature will be higher, generally in proportion to the increase in the main steam pressure. Section - 6 Page 17 of 21

71 With supercritical pressures, because of the greater steam pressure range in the turbine from inlet through to the condenser, there is greater scope for including an extra stage or stages of feed water heating. In some plants the top high pressure heater, which heats the return water to the final feed water temperature, takes its bled steam from a tapping on the HP cylinder rather than from the usual position at the outlet of the HP cylinder. This enables an even higher feed water temperature to be achieved and thereby provide a further increase in cycle efficiency. Typical feed water temperatures are around 290 C to 275 C compared to around 235 C to 250 C for sub-critical plants. With improved cycle efficiency, i.e. a lower heat rate, there will be a reduction in heat rejected to the condenser. There is a multiplying effect for a given improvement in heat rate. For example, if the heat rate is reduced by say 3.5% due to the use of supercritical pressure and higher steam temperatures, the heat rejected to the condenser is reduced by about 6.4%. The percentage reduction in the sizing of the condenser and cooling towers is nearly two times the percentage reduction in heat rate. In addition the water usage for a wet cooling tower will also reduce in the same proportion Efficiency Gains It shall be noted that, as the pressure is increased, so the gains made by increasing the steam temperatures are marginally greater. Other factors which affect the cycle efficiency are the number of reheats, single or double, the condenser pressure, the number of feed water heaters, whether there is a feed water heater bled steam point part-way through the HP turbine, pressure drop through the reheater, etc Environmental Benefits Gains in efficiency are reflected directly in the environmental benefits, i.e. savings in coal consumption that means lower amount of CO2, NOx and SO2 emission per kwh of power generated using efficient supercritical plants Selection of Steam Parameters The next important task is the selection of proper steam parameters. The following aspects shall be considered while selecting the steam parameters. Section - 6 Page 18 of 21

72 Efficiency of the thermal cycle Capacity of the Power Plant Specific steam consumption of the steam turbine Fuel requirement to generate the steam Sizing of equipment and cost implications Investment required for the plant It is a known fact that higher steam parameters, better the efficiency and lesser the steam consumption of the turbine Selection of HP & LP heaters The heat and mass balance calculations have been carried out for following operating conditions and the fuel quantity required has been calculated. a) 100% MCR condition without HP & LP heater. b) 100% MCR condition only with LP heater. c) 100% MCR condition only with HP heater. d) 100% MCR condition with both LP & HP heater. Based on the annual fuel consumption for all these load cases and fuel prices the cost of generation (with the additional investment for heaters with connected piping, valves etc.) works out to be cheaper. Considering the substantial reduction in power generation cost, it is proposed to provide both LP heater and HP heater. Also the heat load on condenser with both HP & LP heaters is less as compared to that without heaters Steam Cycle Configuration for this Plant The various power plant equipment like Steam Turbine, boiler, TDBFP, piping, valves etc. is selected based on the steam parameters. If the higher steam parameters are selected, equipment shall be designed to operate at higher steam conditions and needs special types of materials for construction, special manufacturing process etc. This will further increase the cost of the equipment. Hence, the equipment cost is directly proportional to the steam parameters. Considering on the above facts it is preferable to select optimum steam parameters without compromising the efficiency and optimum cost of plant and equipment. Hence it is recommended to consider 256 ATA, 568 C as the super heating steam Section - 6 Page 19 of 21

73 parameters for the boiler. Considering the auxiliary consumption and the capital cost of equipment, this steam parameters is the most preferred parameter. The broad configuration of steam-water cycle is furnished in the Heat and Mass Balance diagrams (HMBD). The Heat Balance Diagram is enclosed in Drawing No. CCE ME Supercritical Plant Manufacturers in India At present, Bharat Heavy Electricals Ltd. (BHEL) is the only manufacturer of supercritical thermal power plants in India. BHEL has Technical Collaboration Agreement with Alstom, France for the manufacture of once through boilers of both single pass and two pass designs used in supercritical plants. The agreement provides for transfer know how from Alstom to BHEL. BHEL, also, has Technical Collaboration Agreement with Siemens, Germany for the complete range of Steam Turbines and Generators. BHEL will be able to manufacture large unit rating machines of Siemens design under their agreement. BHEL is implementing capacity addition at its Hardwar plant for Steam turbine and Generator and at Trichy plant for Boilers to augment its manufacturing capacity for thermal units of existing range as also supercritical sets of 800 MW and 1,000 MW. In addition to BHEL, Larsen & Toubro Ltd (L&T) has Cooperation Agreement with Mitsubishi Heavy Industries Ltd. (MHI), Japan for transfer of technology for supercritical boilers. Under the agreement, MHI will transfer design and engineering know-how to L&T who will initially manufacture part of the boiler in India and increase indigenous content in a phased manner Supercritical Plant Manufacturers There are a number of large manufacturers of supercritical plants in the world. The main manufacturers are: Siemens AG, Germany Alstom SA, France Mitsubishi Heavy Industries Ltd., Japan Technoprom Export, Russia Doosan Heavy Industries, Korea Babcock Hitachi, Japan Ishikawajima Harima Heavy Industries (IHI), Japan Section - 6 Page 20 of 21

74 Toshiba Corporation, Japan Hitachi Ltd, Japan Harbin Power, China Dong Fang Electric, China Shanghai Electric Corporation, China Hitachi Ltd, Japan General Electric Power System, U.S.A, Ansaldo Energia, Italy. Bharat Heavy Electricals Limited, (BHEL) Delivery Periods Manufacturing capabilities for supercritical plants are available in India presently with two manufacturers. Manufacturing capabilities for supercritical and ultrasupercritical plants are available, however, with a large number of manufacturers in other countries and some of them have some manufacturing or commercial presence in India already. Choice of a manufacturer suitable to meet specific requirements of any developer at an economical price is available. The main problem, at present, is the comparatively long delivery period on account of the order books of most of the manufacturers being full already. Shorter delivery periods are likely to invite higher prices and a balance has to be arrived at between the benefits of early commissioning as against those of lesser initial capital cost. Section - 6 Page 21 of 21

75 Section 7 Technical Features of Main Plant Equipment General The plant comprises of 2 units of Steam Generator and Steam Turbine Generator with a gross power output at generator terminals of 800 MW each at 100% Turbine maximum continues rating (TMCR), with the total capacity of 1600 MW. The thermal cycle for the plant has been designed in accordance with the latest trends and concepts prevailing in the field of power plant design Heat Balance Typical Heat Balance Diagram for 800 MW is enclosed as Drawing No. CCE ME This drawing outlines the basic cycle, flow parameters, pressure, temperature and enthalpy at each of the points of the cycle. The plant heat rate at full load is of the order of 2100 Kcal / kwh for 01 unit of 800 MW with zero cycle makeup and cold / hot circulating water temperature of 32 / 42 deg C Steam Generating Units The steam generator will be sliding pressure supercritical, once-through type, utilizing a Tangential Firing System for NOX control. Boiler is a single reheat, variable pressure operation, with balanced draft furnace conditions. The unit is capable of firing the range of pulverized coals as a Main fuel. The steam generators are coal fired with Heavy Furnace oil firing (HFO) provision upto 30% Boiler Maximum Continuous Rating (BMCR) for low load operation & flame stabilization and Light Diesel Oil (LDO) firing provision to a maximum of 10% BMCR as secondary fuel and start -up fuel respectively The steam generating unit for 800 MW will be sized for 2600 TPH steam flow at, 256 ATA steam pressure and 568 C main steam temperature, 595 C reheat temperature with at 100% MCR Super heater outlet with design consideration of 100% Indian coal GCV of 3100 Kcal/kg at minimum condition and maximum condition of GCV 5500 kcal/kg of Imported coal. This will ensure adequate margin over the requirement of Turbine at 100% MCR to cater for auxiliary steam. Section - 7 Page 1 of 28

76 a) Auxiliary Steam requirement for soot blowing operation, fuel oil system and also for start-up of any adjacent unit. b) Deaerating of the steam generating units with ageing. Steam generator will be designed to operate with "the HP Heaters out of service" condition (resulting in lower feed water temperature at Economizer inlet) and deliver steam to meet the Turbo generator requirement at 100% MCR. The steam generator will be suitable for operation with 60% capacity HP-LP Turbine bypass system envisaged for Turbo generator. The horizontal economizer section will be of no steaming type with provision for recirculation during start-up, chemical cleaning etc Salient Features of the Proposed Boiler Once Through sliding pressure supercritical boiler Vertical Tube Universal Pressure / Spiral Wound Universal Pressure Sliding pressure Conventional Two-pass Radiant reheat Balanced draft Low load start-up system up to 40%BMCR load. Tilting Tangential burners Side mill layout, cold PA system Two (2) axial reaction FD fans Two (2) axial reaction PA fans Two (2) axial reaction ID fans Two (2) regenerative Tri-sector air heaters Ten (10) vertical spindle bowl mills (8W + 2S) Ten (10) gravimetric feeders (Microprocessor Based) (8W + 2S) ESP with 50 mg/nm 3 outlet dust emission (with all fields in service) Micro-processor based BMS, SADC and SB controls. The once-through system is characterized by its unique arrangement of the evaporator sections in the flow system and by the water separator that is placed at the end of the evaporator sections. In a once-through system, the water and steam flow only once through the evaporator circuit and no recirculation is employed. At the outlet of the evaporator walls, or water walls, the steam Section - 7 Page 2 of 28

77 produced is slightly superheated. In the load range between the minimum oncethrough load and the maximum load, the medium is always in a superheated condition and the water separator operates in a dry mode. The gas side heat transfer parameters of a once-through system are the same whether the steam conditions are subcritical or supercritical. Therefore, experience gained in subcritical boilers can be fully utilized for supercritical boilers. The advantage of the once-through system is that there is no fixed point at which the water wall system ends and the superheater system starts. This system can operate with a very wide range of fuels and at different states of furnace cleanliness. Below the minimum once-through load, approximately 40% BMCR, the flow in the water walls is kept above a minimum constant value. At low loads, a mixture of water and steam leaves the water walls and the water separator operates in a wet condition. Care has been taken in the location of the water separators to ensure a smooth transition from the recirculating water wall flow mode to the once-through flow mode. In addition, no significant steam temperature excursions occur at the superheater outlet. Sliding pressure supercritical once-through boilers have water separators integrated into their circuits. Above minimum loads, the separator is only a transit element. Below minimum once-through load, it performs its separation function. During start-up and low load, the steam water mixture is separated in the separator with steam going to the superheaters and water to the start up system. Above the minimum once-through load, the mass flow rate in the water walls is large enough to cool the water wall tubes adequately, so that the start up system is no longer needed in operation Furnace The boiler is a two-pass design of gas-tight welded-wall design. The boiler is of dry bottom type with vertical tubes enclosing the furnace from the coutant bottom to evaporator outlet. Section - 7 Page 3 of 28

78 The complex properties of coal and its ash have a major impact upon the design of the unit. The coal and ash must be carefully analyzed, correctly interpreted, and appropriately applied to the design. It is the nature of the coal to be fired that ultimately determines the configuration and size of the furnace and the boiler. The combustibility of the coal, the ash content and the ash chemistry determine the slagging and fouling properties. The furnace dimensions and firing system arrangement must reflect the resulting fuel ash slagging characteristics. While the ignition of coal particles and complete combustion must be achieved, sufficient radiant surfaces must be provided within the furnace to lower the gas temperature at the inlet to the convection heating surfaces to a level that eliminates sticky deposit on these surfaces Economiser Economiser helps to improve boiler efficiency by extracting heat from flue gases discharged from the final reheater section of a radiant-reheat unit. Heat is transferred to the feed water, which enters at a temperature appreciably lower than that of saturated steam. Economiser is arranged for downward flow of gas and upward flow of water. Feed water and/or recirculated water enter from a lower header and flows through horizontal tubing comprising the heating surface. Return bends at the ends of the tubing provide continuous tube elements, whose upper ends connect to headers. This header is connected to the lower water wall headers through connecting links. Design the economizer for counter flow of gas and water results in maximum log mean-temperature difference for heat transfer. Upward flow of water helps avoid water hammer, which may occur under the some operating conditions. The proposed economizer is an in-line, bare tube arrangement Sliding pressure By adopting the sliding pressure operation with lower boiler pressures at partial loads, the plant heat rate can be improved at partial loads due to 1. Improvement of high pressure (HP) turbine efficiency 2. Reduced auxiliary power consumption by boiler feed pumps 3. Higher steam temperature at the HP turbine outlet. Section - 7 Page 4 of 28

79 In addition to the plant efficiency advantages, there are other benefits such as reduction in start-up time, increase in ramp rate and reduced erosion of bypass valves Superheater and Reheater The superheater and reheater design depends on the specific duty to be performed. For relatively low final outlet temperatures, superheaters solely of the convection-type are generally used. For higher final temperatures, surface requirements are larger and of necessity, superheater elements are located in high gas-temperature zones. Wide-spaced platen superheaters or reheaters of the radiant type are then used as a standard boiler designs. Convection sections are usually arranged for essentially pure counter flow of steam and gas, with steam entering at the bottom and leaving at the top of the pass, while gas flow is opposite. This arrangement allows a maximum log meantemperature difference (LMTD) between the two media and minimizes the heating surface in the primary sections. From the outlet headers of the vertical water walls, the fluid is led to a water separator. After the water separator, the steam flows to the steam-cooled roof. The subsequent steam path is through the back pass walls, primary superheat platen (located in front of the furnace nose), de-superheater and finally through the finishing superheater which is located in the horizontal pass. All superheater surfaces are located on a wide pitch so that any ash deposits which may form on the elements can be easily removed. The inlet to the reheater is in the rear pass of the boiler. Reheat steam passes through the horizontal sections in the rear pass, through the pendant at the inlet of the backpass and then to the reheater finish platens located in the horizontal pass (located between platen SH and final SH) Superheater and Reheater Desuperheater A superheater desuperheater is located between the primary superheater platens and the superheater finishing section. A reheater desuperheater is provided between horizontal RH and final RH used for emergency and upset conditions. Section - 7 Page 5 of 28

80 These desuperheaters, including the necessary spray-type internals, are supplied and used to control final steam temperatures over varying loads and fuels Steam Temperature Control For both the fuel and auxiliary air in the Firing system, vertically-adjusted nozzle tips are designed within the windbox to direct the air and fuel up or down (± 30 degrees). Simple lever arms within the windbox control the adjustable air and fuel nozzle tips and all are driven by a single pneumatic drive outside the windbox. This mechanism gives Tangential-firing the unique and significant capability of raising or lowering the flame pattern within the furnace. When tilted down, more radiant heat is absorbed in the furnace and the gas temperature available to the superheater and reheater is reduced. When tilted up, the reverse occurs. The unique tilting feature of firing gives the operator the ability to control superheater and reheat steam temperature with the firing equipment (firing rate for SH, tilt position for RH) and use desuperheater spray water for trim or precision control. By this technique, desuperheater spray water is minimized, resulting in significant gains in turbine heat rate. The amount of desuperheater spray water can be kept at minimal values over a wide range of furnace conditions and loads by placing the tilts in a mode that automatically controls the reheat temperature. Thus, as firing rate is modulated to control superheat temperature, the tilts are in constant movement, compensating for the continuously changing conditions of the furnace due to wall soot blower, load changes and variations in ash composition Boiler Pressure Parts The boiler has convection heat transfer areas located inside a box formed by welded membrane walls. In these, wall openings are provided for wind boxes, flue gas outlet, access, inspection doors and soot blowers. The boiler and its auxiliary equipment are designed and arranged in such a manner that all parts can be inspected with minimal effort. All important parts are accessible by platforms. Section - 7 Page 6 of 28

81 7.3.9 Boiler Buckstay Arrangement The boiler walls are equipped with buck stays arranged at suitable spacings. They are designed to take up forces due to positive and negative gas pressure excursions, wind and seismic conditions. They are positioned outside of the boiler insulation and are connected to the boiler wall by stirrups. These stirrups permit a free relative movement between the cold buckstay and the hot boiler wall. The fix point of the horizontal displacement is set in the centerline of the wall. Corner retainer plates transfer the forces from the buck stays into tie channels on the adjacent membrane walls or directly into the adjacent membrane walls. Boiler guides connect the buck stays to the steel building structure Openings in the Membrane Walls Inspection openings for fireball observation are provided. The convection heating surface and membrane walls are accessible by openings in the walls at all necessary positions Superheater, Reheater and Economizer Assembly Supports The horizontal economizer assembly tubes are supported by mechanical strap supports. Hanger tubes support the horizontal tube assemblies of the reheater. These hanger tubes and the vertical tube assemblies of the superheater and reheater are supported by high crown seals above the boiler roof. These high crown seals support the assembly weight while providing a gas tight boiler roof seal Boiler Suspension Hanger rods from the steel structure grid at the pressure part support level (PPSL) suspend the boiler membrane walls. The upper end of each hanger rod is provided with a thread and nut. This allows an exact vertical positioning of each wall during erection and readjustment, if necessary, after initial operation. The purpose of the furnace support system is to transfer the weight of the furnace to the structural steel in a manner that accommodates inherent movements and expansions, occurring during operation, without imposing any life-limiting loads on the pressure parts. Section - 7 Page 7 of 28

82 Pressure Part Support Level (PPSL) All membrane walls, tube assemblies, headers, and internal boiler piping are suspended from the PPSL, consisting of a grid of steel beams. This suspension principal allows free cubical expansion of the boiler. All load transfer points are located at the PPSL elevation, which facilitates easy access to the individual hanger Boiler Steel Structure The boiler steel structure consists of main columns with vertical bracing, horizontally braced platforms, and unbraced intermediate platforms. The horizontal and vertical bracing transfer loads due to wind and seismic to the foundation. All connections between main columns, bracing, and platform members are bolted Platforms, Walkways and Stairs A system of platforms and stairways, as required for the proper operation and maintenance of the boiler building components Walkways and stairs facilitate access to all platforms. Platforms, walkways, and stairs are covered by steel grating, except for the area adjacent to the windbox where checker plate is used Soot blower System One of the most important boiler auxiliary operations is the on-line fireside cleaning of heat-absorbing surfaces. Not only is it important for proper heat transfer, but also to prevent sections of the boiler from becoming severely plugged. Plugged sections can restrict gas flow and cause load limitation as well as tube erosion due to high local velocities. Of the major fossil fuels, coal alone requires a large complement of permanently installed soot blowing equipment. Coals and coal ash resulting from combustion vary widely throughout the world, and even from region to region of the same country. Depending on certain properties, boilers burning various fuels require different soot blowing systems. Section - 7 Page 8 of 28

83 In the boiler furnace, the concentration of wall blowers depends upon factors such as the ash-fusion temperatures Retractable Blowers A sufficient quantity of long retractable soot blowers is provided. This long retractable-type soot blower is the most effective way to clean radiant and convective heating surface. It normally uses two 180 o opposed-cleaning nozzles at the tip which emit a high-pressure steam source perpendicular to the lance. While the lance traverses the boiler, it rotates, forming a helical blowing pattern, which effectively cleans the tubes and spaces between tubes in a superheater, reheater or economizer bank. In widely spaced platenized sections, these nozzles are angled slightly, leading and lagging the perpendicular to gain more dwell time on the tube surface. The effective cleaning range of retracts depends upon the gas temperature in the area to be cleaned, the ash characteristics of the particular fuel being fired and the spacing of the particular section Firing System Tilting Tangential Firing Systems Tangential firing systems have been used extensively all over the world to fire many types of solid, liquid and gas fuels including anthracite, bituminous and brown coals. Tangentially fired steam generators inject the fuel and air streams from wind boxes in the furnace corners, tangent to an imaginary circle in the center of the furnace. A single rotating flame envelope (commonly referred to as a fireball) is created. The impingement of laterally adjacent streams promotes bulk mixing for complete combustion. Since fuel/air mixing and corner ignition stability occur by global vortex rather than local swirl mechanics, the phrase the furnace is the burner is uniquely applied to tangentially fired units. When compared to similarly sized wall-fired furnaces, tangentially fired furnaces have greater heat absorption, lower peak heat fluxes, and lower average gas temperature. The latter item is especially important when firing coals with moderate-to-low ash fusion temperatures. Due to the unique furnace aerodynamics, the water wall heat absorption profile is consistent at any crosssection of furnace height. Section - 7 Page 9 of 28

84 Tangentially fired boilers have demonstrated low NOx production. The long diffusion flames emanating from each corner, plus the large amount of internal gas recirculation generated by the cyclonic fireball, moderate fuel and air mixing. This forms the basis of an inherently low NOx system. In contrast, wall-fired boilers utilize groups of individually self-stabilizing burners that do not use global furnace flow patterns to achieve uniform fuel and air mixing. As a result, wallfired arrangements, even those employing separated over fire air, typically create local zones of high temperature and oxygen concentration that lead to high NOx formation. Global and local staging techniques have been used to minimize O2 availability during the critical early phases of combustion when the volatile nitrogen species are formed. Staged combustion minimizes NOx emissions because the initial fuelrich conditions promote the formation of N2 from the volatile nitrogen species. Overfire air (OFA) staging, which sets the global firing zone stoichiometry, has been used. In summary, tangential firing offers several advantages over other types of burner systems. Because the vortex effectively fills the lower furnace volume, heat absorption there is increased, reducing both local and peak gas temperatures. This decreases slagging potential and thermal NO x production. Waterwall heat absorption profiles are consistently predictable over the height of the furnace, regardless of which pulverizers are in service or unit load. With the tangential firing system, steam outlet temperature can be held constant over load by raising or lowering the fireball within the furnace via pitch adjustment (tilt) of the fuel and air nozzle tips. Finally, the long diffusion flames from each corner, plus the large amount of internal gas recirculation generated by the cyclonic fireball, moderate the fuel/air mixing rate and form the basis of an inherently low NOx combustion system Pulverizers The pulverizing system is a highly efficient, reliable and flexible system for meeting a wide range of solid fuel preparation needs. Section - 7 Page 10 of 28

85 Bowl mill type pulverizer has been continually refined to meet the ever-changing service conditions. Low power consumption, low maintenance costs, wide capacity range and high availability. Ten (10) (8W+2S) numbers of pulverizers with adequate capacity are envisaged. These mills are capable of achieving 70% < 200 mesh fineness in a worn condition System Operation Pulverizers are used to prepare and deliver fuel to steam generators in a tangential fuel firing system. The pulverizer dries grinds and transports coal to the furnace. Properly prepared coal ensures complete combustion of fuel that result in high boiler efficiencies. Of primary importance in the coal pulverizing process, is assuring the necessary coal product sizing. Coal is fed from a gravimetric coal feeder to the pulverizer through a center coal feed pipe onto a revolving bowl. Centrifugal force causes the coal to travel toward the outboard perimeter of the bowl. As the coal travels up the bowl, it passes through the grinding zone between the grinding ring and grinding rolls. Grinding force is imparted on the coal bed through a pivoting roller journal assembly and controlled by an externally adjustable spring or hydraulic cylinder. The partially pulverized coal continues outward toward the edge of the bowl. A primary air fan and air preheater supply hot air in the required quantities for the coal pulverizing process. The hot air enters the mill side housing below the bowl and is directed upward around the bowl through vanes attached to the circumference of the bowl. As the air passes upward around the bowl, it picks up the partially pulverized coal and the drying and product sizing or classification process begins. The coal/air mixture then enters the primary classifier where heavier coal particles strike the deflector and intermediate liners and are returned to the bowl for further grinding. The lighter particles are carried up and through the deflector. Section - 7 Page 11 of 28

86 Any tramp iron, or dense difficult-to-grind foreign material in the coal feed, is carried over the top of the bowl where it drops through the air stream to the mill bottom. Pivoted scrapers attached to the bowl hub sweep the tramp iron and other material to the tramp iron discharge opening and out of the pulverizer Air and Flue Gas System Air and Flue Gas Draft Systems Air and Flue Gas Draft Systems to be designed with all applicable design criteria including high temperatures, pressures, material properties, fatigue, fan pulsations etc. while maintaining simplicity of construction. The air and flue gas systems are designed to provide combustion air, coal transport air, cooling air, sealing air and to remove the flue gases resulting from combustion Primary Air The primary air system provides air to the pulverizers for drying the pulverized coal and for conveying it to the wind box coal nozzles. A portion of the primary air from the Primary Air fans is directed through an associated primary side of the regenerative air heaters. Here the air is heated by the hot heat transfer elements before it is directed to the hot primary air ducts leading to each of the six pulverizers located at the front of the unit. Cold primary air ducts lead directly from the primary air fan and discharge to the pulverizers inlet duct. The air inlet duct at each pulverizer is connected with both the hot and cold primary air ducts. Temperature control is accomplished by a set of control dampers in both the hot air and cold air ducts Secondary Air The secondary air system provides air for combustion to the wind boxes. The secondary air from the forced draft fans is sent through air preheater. This secondary air is raised to higher temperature by the flue gases in the regenerative air preheater. From the regenerative air preheater, the air is fed to the windboxes through the hot secondary air ducts. In the windboxes, individual compartment dampers distribute the air. Section - 7 Page 12 of 28

87 Regenerative Air Preheater The regenerative air preheater is a highly efficient, compact and versatile heat exchanger. The simplicity of its design and construction permits the regenerative air preheater to operate over extended periods without interruption Fans The draft system for the boiler consists of: a. Forced draft fans Two numbers Axial reaction, single stage, variable pitch blade control with Silencer and drive motors. b. Induced Draft fans Two numbers Axial reaction, single stage, variable pitch blade control and drive motors. FD and ID fans are capable of maintaining the balanced draft conditions in the furnace over the entire load range. The boiler is also equipped with the following fans which form a part of the coal preparation and firing system. a. Primary air fans Two numbers. Axial reaction, two stage, variable pitch blade control with silencer and drive motors. b. Seal Air Fans Two number Radial Fans with drive motors Axial Reaction Fan (Single Stage) These Fans are reaction type axial flow machines with profiled blades (aerofoil shape). The rotor of this fan is of overhung design i.e. the fan impeller is fixed at one end of the shaft. To the other end of fan impeller, hydraulic servomechanism is assembled. Section - 7 Page 13 of 28

88 These fans possess a fairly high degree of reaction whereby major portion of the static pressure rise takes place in the impeller itself and the rest in diffuser. Regulation of fan from no load to full load is performed by changing the pitch angle of blade profile on all blades simultaneously during operation. This is achieved through a sophisticated servo - mechanism (Hydraulic servo motor) externally actuated by a power cylinder or servomotor and forced lube oil system. The major sub-assemblies of the fan are as follows: 1. Stator parts 2. Rotor assembly 3. Rotor bearings Stator Parts This consists of suction chamber, impeller housing and diffuser. The suction chamber is a fabricated structure made out of low carbon steel plates adequately stiffened. The suction chamber houses a plate formed fabricated bullet shaped core, inside of which the main bearing housing is mounted. The bullet further serves the purpose of guiding the fluid in to the impeller. The impeller housing is bolted to the suction chamber flange. The inside diameter of the housing is machined to maintain proper and uniform radial clearance between impeller blades and housing. An inspection door is provided on the housing. The fabricated diffuser connected to the other end of impeller housing houses an inner cylindrical core and outlet fixed guide vanes. The medium flows in the annular space between the core and diffuser. A manhole door is provided at the outlet end of the diffuser core for attending to the assembly and maintenance of Hyd. servo mechanism Rotor Assembly The rotor assembly consists of impeller and shaft. The impeller assembly consists of support body housing, blade shafts, blade bearings, hub, aerofoil blades and hyd. servo motor. The blades are made of Aluminium alloy with hardness of approximately 75 BHN (min) for cold air application viz. FD Fan and for ID fan they are made of Cast Iron; the blades will be subjected to natural frequency test. The shaft is made from forged steel and fully machined. One end of the Section - 7 Page 14 of 28

89 shaft is connected to the impeller and the other end is connected to the drive through spacer coupling of BHEL make. The shaft is dynamically balanced separately and the impeller components are dynamically balanced separately as per ISO Rotor Bearings The rotor is supported in antifriction bearings and lubricated by forced lubricating oil. A thrust bearing is provided to absorb axial loads. Thermometers are provided in the bearing housing for temperature monitoring Axial Reaction Fan (Double Stage) These Fans are reaction type axial flow machines with profiled blades (aerofoil shape). The rotor of this fan is of overhung design i.e. the fan impellers are fixed at both end of the shaft. To the other end of fan impeller, hydraulic servomechanism is assembled. This fan possesses a fairly high degree of reaction whereby major portion of the static pressure rise takes place in the impeller itself and the rest in diffuser. Regulation of fan from no load to full load is performed by changing the pitch angle of blade profile on all blades simultaneously during operation. This is achieved through a sophisticated servomechanism (Hydraulic servo motor) externally actuated by a power cylinder or servomotor and forced lube oil system. The major sub assemblies of the fan are as follows: 1. Stator parts 2. Rotor assembly 3. Rotor bearings Stator Parts This consists of suction chamber, impeller housing and diffuser. The suction chamber is a fabricated structure made out of low carbon steel plates adequately stiffened. The suction chamber houses a plate formed fabricated bullet shaped core, inside of which the main bearing housing is mounted. The bullet further serves the purpose of guiding the fluid in to the impeller. The impeller housing is bolted to the suction chamber flange. The inside diameter of the housing is machined to maintain proper and uniform radial clearance between impeller blades and housing. An inspection door is provided on the housing. The Section - 7 Page 15 of 28

90 fabricated diffuser connected to the other end of impeller housing houses an inner cylindrical core and outlet fixed guide vanes. The medium flows in the annular space between the core and diffuser. A manhole door is provided at the outlet end of the diffuser core for attending to the assembly and maintenance of Hyd. servo-mechanism Rotor Assembly The rotor assembly consists of two impellers and shaft. Each impeller assembly comprises of support body housing, blade shafts, blade bearings, hub, aerofoil blades and a common hyd. servo motor. The blades are made of Aluminium alloy. Both the ends of the shaft are connected to the impeller and the fan rotor is connected to the drive through spacer coupling. The shaft is dynamically balanced separately and the impeller components are dynamically balanced separately as per ISO Rotor Bearings The rotor is supported in antifriction bearings and lubricated by forced lubricating oil. Thermometers are provided in the bearing housing for temperature monitoring Boiler Feed Pumps and Drives 2 x 50% Turbo Driven Pump + 2 x 30% Motor Driven Boiler feed pumps are envisaged. Each Boiler Feed Pump will be Multistage Horizontally split type twopiece inner casing, double volute structure, opposed type impeller arrangement, with booster pumps Electrostatic Precipitator Each steam generating unit shall be installed with Six (6) Electrostatic Precipitators comprising eight (8) bus sections in the direction of gas flow and two (2) bus sections perpendicular to the gas flow. All the fields of the precipitators are provided with 400 mm electrode spacing considering One (1) field out of service. The ESP would have a collection efficiency of around 99.99%. The outlet dust concentration from the chimney will be limited to 50 mg/nm 3 as per the latest regulation of Central Pollution Control Board. Each ESP will be provided with Section - 7 Page 16 of 28

91 Ninety Six (96) ash hoppers having capacity suitable for storing ash collected in at least one (1) shift operation of the Boiler at 100% MCR. The flue gas shall be drawn from air preheated outlet and guided through adequately sized ductwork into independent gas streams of ESPs of each steam generator. Similarly, the flue gases after the ESPs shall be led to the suction of the induced draft fans. As the steam generators are designed to burn fuel oils specified in conjunction with pulverized coal during start-up and at low loads for warm up and flame stabilization, the ESP shall be designed by taking into account the entire characteristics of expected combination of fuels to be fired Auxiliary Boiler One (1) No Water Tube type, natural circulation, pressurized furnace, LDO fired, outdoor type Auxiliary Boiler of 70 TPH capacity with rated steam parameters at super heater outlet as 19 ata pressure and 215 C temperature, complete with piping, valves, fittings, mounting, draft plant, fuel oil pressurizing & firing system, boiler safety & protection system, associated feed water systems, boiler filling system, chemical dosing system, ducting, dampers, insulation & cladding, lifting tools and tackles, chimney, approach & maintenance platforms, including supporting structures, Electricals, Control & Instrumentation. One (1) no of feed water storage tank for half an hour storage capacity of auxiliary boiler operation at full load is envisaged. Base plates, foundation bolts, Anchor materials, matching pieces, inserts & packing shims etc. as required for Auxiliary boiler and associated equipment. Auxiliary Boiler including its interlock and protection system shall conform to NFPA Brief Technical Specification of Boiler and Auxiliaries All the below values are typical applicable for each unit. S. No Description Units Values A. Boiler 1. Type of Boiler - Pulverized Coal Fired Section - 7 Page 17 of 28

92 S. No Description Units Values Main Steam 2. Superheater outlet steam flow T/hr Steam pressure at SH outlet ATA Steam temperature at SH outlet C 568 Reheat Steam 5. Reheat steam flow T/hr Steam pressure at RH Inlet ata Steam pressure at RH outlet ata Steam temperature at RH inlet C Steam temperature at RH Outlet C Feed water temperature at economiser inlet C Flue gas outlet temperature C Excess air(at 100% MCR) % Superheat temp control - By spray 14. RH temp control Safety Valves - By burner tilt + Spray + excess air adjustment As per system requirement on drum, SH, RH etc. 16. Soot blowers - As per manufacturers design 16. Regenerative Air preheater - Motor driven 17. Ambient air temperature C Maximum temperature entering close spaced platens C As per design requirement Section - 7 Page 18 of 28

93 S. No Description Units Values B Electrostatic Precipitator Number of precipitators per boiler Number of gas paths per precipitator Number of electrical fields (Zones) in series in the direction of the gas flow Total number of electrical fields per boiler Space between the centers of collecting electrodes across the gas path Nos. Six (06) Nos. Two (02) Nos. Eight (08) Nos. 96 mm Outlet dust concentration when all fields are working mg/nm 3 (max) Specific collecting area m C. Boiler Feed Pump 1. Number of BFP sets per STG unit Nos. 2 x 50% Turbo driven & 2 x 30% Motor driven 2. Liquid Handled - Boiler feed water 3. Rated capacity m 3 / hr Feed water temperature at pump ºC Type of Coupling - variable speed Fluid Coupling D. Auxiliary Boiler 1. No. of Auxiliary Boiler - One (1) No. Outdoor installation type, 2. Type - 3. Feed Water Pumps Nos. natural circulation, pressurized furnace, water tube boiler suitable for firing LDO 2 x 100 % Motor Driven Type Section - 7 Page 19 of 28

94 S. No Description Units Values 4. Pump Type - Identical multistage centrifugal pumps complete with drive Steam Turbine Generator ( STG ) Steam Turbine The steam turbine of 800 MW will be a horizontally split, multi cylinder (one HP, one IP & two LP) 3000 RPM multistage, tandem compound, single reheat, condensing type unit uncontrolled extractions for regenerative feed water heating. The turbine will be designed for main steam parameters of 247 ata, C at emergency stop valves of H.P. turbine High-Pressure Turbine (HP Turbine) The HP Turbine is a double shell casing with vertically guide blade carrier and axially split barrel type outer casing Intermediate-Pressure Turbine (IP Turbine) The IP-turbine is of double flow. The double-shell casing consists of a horizontally split inner and outer casing Low-Pressure Turbines (LP Turbine) Each LP-turbine consists of two double-flow units with a horizontally split casing. The LP turbine will exhaust against condenser pressure of about 0.10 ata. The Turbo-generator set will be designed for a maximum throttle steam flow at Turbine Valve Wide Open (V.W.O.) condition of about 105% of Turbine MCR condition. The turbine will be rated for a minimum of 800 MW and shall be capable of both constant variable pressure operations as well as with HP heater out. HP steam turbine receives steam from the boiler Superheater through the HP governing and emergency stop valves. The exhaust from the HP steam turbine is given to the IP steam turbine. IP steam turbine is supplied with steam from the reheater through the IP emergency stop valves. The optimum throttle Section - 7 Page 20 of 28

95 conditions are normally determined considering minimum pressure and temperature drop in the main steam and re-heat steam lines. The turbine has an over speed limit of (+) 10%, the critical speeds being at (-) 15% below and (+) 15% above the normal speed while the turbine blading being tuned for a frequency variation from (+) 3% to (-) 5%. Dryness of exhaust steam will be more than 90%. All essential controls and safety interlocks are provided. The turbine is complete with two (2) 100% (1 Working + 1 Standby) condensate extraction pumps, two (2) 100% (1 Working + 1 Standby) vacuum pumps, motor operated vacuum breaker valve, gland steam condenser, deaerating heater, coolers, steam and other miscellaneous piping and valves associated with the boiler and the steam turbine, including all control stations and instrumentation. The turbine auxiliaries shall comprise of the following: - Automatic turbine test gear - Low vacuum unloading gear - Turbine governing system - Initial pressure regulator - Control fluid system - Turning gear and oil pumps (AC/DC motor driven) - Turbine oil system with centrifuge & vapour extractor, for bearings, generator seals, jacking, turning gear etc. - AC/DC motor-operated Jacking oil pumps - Lube Oil purification system - Oil Cooler - Automatic Turbine Run-up System (ATRS) - Stress Evaluator H.P. and L.P. Turbine bypass station (60 percent boiler MCR capacity) is provided to act not only as a protection to the turbine during pressure rise resulting from sudden load throw off but also to enable operation of the unit at loads lower than the control load. Further HP/LP bypass would permit quick, repeated hot starts of the unit on its tripping. A fully automatic gland sealing system is provided and the turbo-generator is equipped with the following: Section - 7 Page 21 of 28

96 a) Electro-hydraulic governing system backed up by Hydro-mechanical system ensuring stable operation under grid fluctuation and b) Hydraulic oil driven rotor turning gear and c) Self contained lubricating oil system for supplying oil to Turbine and Generator bearings to the governing and control system and also to Generator Seal Oil System Condensing Equipment Two (2) nos. of single / double pass surface condenser for each unit having a different exhaust pressure of / ata will be provided at steam side respectively, and cooling water side of condensers in series with adequate hot well capacity capable of maintaining the required vacuum while condensing steam at the maximum rating of the turbine, will be provided for each unit.. The condenser is of box type construction with divided water box design and is provided operation of one half of the condenser while the other half is under maintenance. The steam space will be rectangular cross-section. The condenser is provided with integral air cooling section from which air and non-condensable gases are drawn out with the help of air evacuation equipment. Two vacuum pumps (2x100%) of air evacuation system for each condenser will be provided. The operation of vacuum pump system for each condenser is automatic and is achieved through Automatic Turbine Run-up System (ATRS). The water boxes of the condenser will have smooth entry and uniform distribution of cooling water to all the tubes. Hot well (of adequate capacity) is divided longitudinally for detecting contamination of the condensate in each condenser half. Three (3) vertical condensate extraction pumps each of 50 % capacity per set are envisaged to pump condensate from condenser hot well to the Deaerator through the Drain Cooler, Gland Steam Condenser and various low pressure heaters. Three (3) % capacity steam ejector alternately vacuum pumps are provided to maintain the vacuum in the condenser by expelling the noncondensable gases. Section - 7 Page 22 of 28

97 Motor operated butterfly valves and expansion joints are provided at both CW pump and condenser ends. Condenser circulating water piping shall be arranged for two inlets at the top and two outlets at the bottom. Cleanliness factor for condenser design will be 85 percent while oxygen content of hot well water would be maintained around cc / liter. Hotwell capacity will be equivalent to 5 min. duration. The temperature rise of circulating water will be limited to 9.0 C (maximum) under the rated steam entry into the condenser. Water velocity through tubes is limited to 2 m/s. The circulating water is drawn from the circulating water sump. A closed circuit employing Demineralized water for other auxiliary cooling requirements is envisaged. The DM water is cooled by the circulating water in adequately sized plate type heat exchangers and sea water booster pump is envisaged. Necessary piping and controls are provided. The Following parameters shall be maintained at DM Water makeup to Condenser: Characteristics : Value Silica : 0.02 ppm as Sio2 Iron as Fe : Nil TotalHardness : Nil ph Value : Conductivity : Not morethan 0.1 excluding the effects of free Co Feed Cycle Equipment Four (04) low pressure (LP) horizontal / vertical feed water heaters are envisaged. The LP heater 1 is mounted in the condenser neck and uses an external drain cooler. LP heater 2, 3 and 4 can be individually isolated and bypassed. The unit is provided with a variable pressure Spray cum-tray-cum-reboiling type deaerating heater with a feed water storage tank of adequate capacity. Deaerator is designed to deaerate all the incoming condensate and drain flow to keep the oxygen content of the condensate below the permissible limit of cc / litre. The deaerator normally operates by taking extraction steam from the Section - 7 Page 23 of 28

98 IP turbine except during low load operation and start up when it is pegged with steam drawn from the auxiliary steam header. Deaerator will be elevated (located at 27.5 M level) to provide sufficient NPSH for the boiler feed pumps. Three (03) high pressure (HP) horizontal / vertical heaters are provided with both drain cooling and desuperheating zones in addition to the normal condensing zone. HP heaters are provided with individual bypasses to allow isolation and maintenance. ASME-TWDPS-I recommendations for preventing water damage to turbine shall be followed Brief Technical Specification of Steam Turbine and Major Feed Cycle Equipment S. No Description Units Values A Turbine Type - Tandem Compound Number of cylinders - Multi Cylinder 3. Type of governing - Digital electro hydraulic Speed RPM 3000 Maximum continuous rating per unit KW Mail Steam at HP Turbine emergency stop valve a. b. Pressure ATA 247 Temperature C Hot reheat steam at IP Turbine terminal point a. Pressure loss from HP Turbine outlet terminal point to IP Turbine inlet terminal point ata 4.92 b. Temperature C 593 Section - 7 Page 24 of 28

99 S. No Description Units Values 8. Condenser Pressure ata Final feed water temperature C Turbine speed min SH steam flow required for with 0% make-up 12. Circulating water to condenser per unit (@ t is 10ºC) T/hr m 3 /hr Maximum temp. rise of circulating water C Turbine Heat Rate Kcal/Kwh 1850 B. Condenser Cooling water Pumps 1. Number of pumps required per unit - 5 (4 W +1 S) 2. Rated capacity m 3 /hr Water inlet temp C 34 0 C (max) for condenser design. 4. Number of stages - Two (02) 5. Location - Indoor Generator The generator unit comprises a two-pole, hydrogen-cooled turbo generator with direct water cooling for the stator winding, which is directly coupled to the turbines, a rotating-diode brushless excitation system directly mechanically and electrically coupled to the generator rotor, a two-channel digital voltage regulator and the requisite supply systems (that is to say, the seal-oil, hydrogen and stator cooling water supply systems) Generator Cooling System The stator winding is directly cooled by primary water and the rotor winding by hydrogen. The heat produced in the other components as a result of losses such as iron losses, friction and stray losses is dissipated by hydrogen cooling. The heat in the core is uniformly dissipated via a large number of axial cooling bores. The hydrogen is circulated inside the gas-tight and pressure-resistant generator Section - 7 Page 25 of 28

100 frame in a closed circuit by a multi-stage axial flow fan mounted on the turbine end of the shaft. The hydrogen coolers are mounted vertically in the generator frame. The demineralised water to cool the stator winding (primary water) is circulated in a closed loop by a pump, with the heat rejected to the secondary water in the primary water cooler Stator Core The core is not sensitive to operating speed vibrations and harmonics of 2 times the operating speed. It comprises stacks of low-loss laminations which are resistant to humidity and varnished on both sides. Axial compression is obtained by prestressed stacking beams on the core back and by nonmagnetic, through bolts. The pretensioning forces are applied via pressure plates and fingers installed at both core ends. As for all turbo generators of this type, the core does not need any maintenance or re-clamping. The requirements associated with capacitive loads on the generator are reliably met by means of highly effective magnetic shielding of the core end zones, optimum stepping of the tooth tips at the core end zones and engineered cooling Stator Winding High-quality mica, selected epoxy resins and tailored vacuum-pressure impregnation (VPI) are characteristic features of the MICALASTIC insulation system used for the stator winding. This high-quality insulation system, whose reliability is ensured by continuous in-process inspections, is the result of consistent development. The bars taped with mica film are immersed in epoxy resin under vacuum and pressed to the required size. As a result, MICALASTIC insulation has excellent electrical, thermal and mechanical properties. The insulation is dimensioned in accordance with heat class F (IEC 34-1), but it is not thermally loaded to more than class B. To ensure that the stator winding cannot work loose and that it does not require any maintenance, the bars are held in place mechanically in the slot region by preloaded slot top ripple springs. These do not restrict thermally induced expansion during generator operation. Particular attention is paid to the area of the stator end windings. Radial support is provided by a sturdy support ring manufactured from glass-fiber laminate wrapped around the stator end windings. Conformable, flexible filler strips Section - 7 Page 26 of 28

101 between the stator bars and the support ring, and between the individual bars form a solid assembly. This assembly is fastened to the bracket with the aid of segmented plates and high-strength insulation bolts. As a result, the end winding and bracket form a rigid, short-circuit-proof assembly Rotor Shaft The rotor shaft is a vacuum-cast monoblock forging. It meets all requirements of today's state of the art in terms of forging, materials science and material testing. Rotor design is based on an in-depth analysis of the rotor flexibility and torsional criticals, of the shaft fatigue levels and the permissible number of starts to ensure that the associated requirements are met under all operating and offnormal conditions Rotor Winding The rotor winding comprises copper conductors containing silver and having low oxygen content. Floating, solid, nonmagnetic end-bells accommodate the centrifugal forces acting on the rotor end windings. The high-strength austenitic end-bell metal is not susceptible to humidity or stress corrosion cracking. The slot end wedges and rotor end-bells are silver-plated to give good contact conditions and thus act in a similar way to a damper winding Bearings and Shaft Seals The rotor shaft is supported in end-shield bearings provided with forced oil lubrication. To prevent shaft currents, the bearing shell supports are installed on insulated pedestals in the end-shield bearing housings. This provides adequate generator bearing insulation. To prevent hydrogen leakage, shaft seals are installed in the area of the bearings. These seals are supplied with oil at a defined pressure to form a radial liquid seal on the shaft Supply Systems MKF / MKG / MKW The hydrogen, seal oil and primary water supply systems comprise all equipment necessary for generator filling, operation, shutdown, standstill and gas purging. The systems are designed in accordance with IEC 34-3 specifying the regulations for erection and operation of hydrogen-cooled turbo generators, and also in Section - 7 Page 27 of 28

102 accordance with the recommendations made in the VDEW guidelines on the improvement of the safety of hydrogen-cooled Generators Excitation System MKC With brushless excitation, an air-cooled exciter unit comprising a salient-pole three-phase main exciter with pilot exciter provided with rotating diodes is directly coupled with the generator rotor. The three-phase current generated in the rotating armature of the main exciter is rectified by the rotating diodes (three-phase bridge circuit) and applied to the rotor winding of the generator via two copper conductors in the shaft center. The permanent pole pilot exciter generates the necessary excitation power for the voltage regulator and main exciter Generator Specification per unit S. No Description Values / unit 1. Rated KW capacity at TMCR : KW 2. Rated KVA capacity : KVA 3. Rated terminal voltage : 27 KV 4. Rated power factor : 0.85 lagging 5. Rated stator current : Amp 6. Rated speed : 3000 RPM 7. Rated frequency : 50 Hz 8. Efficiency at rated power 0.85 p.f : 98.82% (approx.) 9. Short circuit ratio : 0.5 (approx) 10 Rated hydrogen pressure (gauge) : 5 kg/cm 2 11 Type of excitation : Brushless 12 Insulation : Micalastic Section - 7 Page 28 of 28

103 Section 8 Technical Features of Balance of Plants Mechanical Systems Balance of plant includes coal handling plant, Fuel oil unloading storage and handling, Mill rejects systems, ash handling plant, plant water systems, cooling towers, Raw water treatment plant, CW chlorination, RW chlorination system, CW pumps, Condensate polishing unit, Effluent treatment plant, Air conditioning & ventilation system, Fire protection system, Hydrogen generation plant, Compressed air system, Elevators, Miscellaneous cranes & Hoists, Workshop equipments, chemical laboratory etc shall be designed to meet the plant requirements Coal Handling System Coal Requirement The coal requirement for the proposed project can be sourced from Kalinga Block of Talcher coal fields, Mahanadhi and IB valley coal fields in India / Imported coal. The requirement of coal will be as follows: Description Option - I Option II Option - III Option - IV Type of Coal 100% Indian coal 100% Imported coal 70% Ind coal + 30% Imp coal 70% Imp coal + 30% Ind coal GCV in kcal / kg Fuel Consumption for Two (2) Nos. of Boiler in TPH Fuel Consumption per 100 % PLF in MTPA Fuel Consumption per 85 % PLF in MTPA The capacity of coal handling plant for design condition will be estimated as 2000 Tons Per Hour with two streams (1W + 1S) operating at 16 hrs/day considering 100% Indian Coal. Section - 8 Page 1 of 103

104 Coal Transportation TANGEDCO has planned to source the coal from kalinga block of Talcher- Mahanadhi and IB valley coal fields through Coal India Limited and also Imported coal from Indonesia / Australia / South Africa. Further coal can be transported (Indian coal & Imported coal) through sea to Ennore port and stored at coal berth 3 for TANGEDCO. From the coal stockyard, it can be conveyed through the closed conveyors to the proposed site. The fuel system flow diagram is enclosed as Drawing No: CCE ME Dust Suppression As the coal handling plant is prone to fugitive dust it is mandatory to install dust suppression systems in the CHP. Spraying system: sprinklers are used in the stockpile area to suppress the dust; the mechanism is simple; fine atomic particles of water are sprayed on the stock pile & this acts as a blanket. DFDS: dry fog dust suppression system: this is used typically at transfer points & hoppers; the water is sprayed in conjunction with compressed air & these particles adhere to the dust & settle down Dust Extraction system This is used in Bunker silos where the coal is fed from conveyors & falls from a height. The unsettled dust is sucked through fans installed on the roof through bag filters or cyclonic separators & the heavier dust particles are fed back to the bunkers Transfer points Transfer points will be provided at every change of direction of the conveyors and at all elevation change points. This will have structural steel frame work with R.C.C roof and floors. Cladding shall be of metal sheeting Crushing System Unloaded coal is conveyed to crusher house by belt conveyors via pent house and transfer points. Suspended magnets are provided on conveyors at pent Section - 8 Page 2 of 103

105 house for removal of tramp Iron pieces. Metal detectors are also provided to detect non-ferrous materials present in the coal before crushers. Manual stone picking provision will made at a suitable location after penthouse. In line magnetic separators are also provided at discharge end of conveyors for removal of remaining metallic ferrous tramp from the coal before it reaches the crushers. Coal sampling unit is provided to sample the uncrushed coal. One number crusher house will be envisaged for the proposed power plant, having 2 nos. of crushers, (1W + 1S), with reversible belt feeders, flap gates & screens etc. Crushers crush the coal to ( ) 25 mm size and after crushing convey to outgoing conveyors in the coal path through flap gates and reversible belt feeders. Coal sizes which are already less than ( ) 25mm shall get screened through roller screens and conveyed to the same conveyors as indicated above Coal Stacking and Reclaiming system / Stock pile Crushed coal will be sent to stockpile when coal is not required in the bunkers. Stacking / reclaiming of coal will be carried out stacker / Reclaimer moving on rails. The stacker Reclaimer shall stack coal on either side of yard conveyor. During stacking mode coal is fed from conveyors on boom conveyor and while in reclaim mode, yard conveyor discharges coal on the yard conveyor itself for feeding coal to bunkers through conveyors and transfer points. The yard conveyor can be reversible type. Coal stockpile height considered is 10 m. When coal is required in the bunkers and crusher is not in operation, coal will be reclaimed by stacker-cum-reclaimer and fed to coal bunkers through a series of conveyors through various junction towers. Two nos. of Emergency reclaim hopper (ERH) can be provided to reclaim coal by dozers when stacker cum-reclaimer is not in operation. Emergency reclaim hopper can also be used for coal blending. Metal detectors, in-line magnetic separators, Coal sampling unit and Belt weigh scales will be provided at suitable locations. Section - 8 Page 3 of 103

106 Coal Conveying from Crusher House to Boiler Bunkers Coal from crusher house will be conveyed to boiler bunkers through a series of conveyors with necessary flap gates, fixed trippers, motorized Traveling trippers. Inline Magnetic Separators, metal detectors, Electronic belt scales shall be provided at appropriate places, Automatic type Coal Sampling unit, Dust suppression, Dust extraction and Ventilation system will be considered. The scheme for coal handling is enclosed as Drawing No: CCE ME Mill rejects system Pressurized pneumatic conveying system shall be employed for handling of the mill rejects. Each mill reject discharge hopper shall be fitted with a positive pressure pneumatic conveying vessel which shall discharge the mill rejects through pipe lines in a storage silo. Each unit shall be provided with an independent silo having collection capacity of 16 Hours. The transmitting vessel shall operate on level probe mode with timer back up. Each mill is provided with collection and transportation equipment. Each stream of mills shall be connected to storage bunker then the mills are conveyed by the compressed system Ash Handling System The ash handling envisages Dry type extraction for disposal of bottom ash and fly ash. In case of emergency bottom ash will be extracted in wet form and stored in existing ash dyke Design Parameters The ash handling system is designed for 100 % of Indian coal considering 45 % of ash (worst condition) to meet the following parameters: Description Coal consumption at full load for 2 Units 100% Indian coal 1084 TPH Ash content in coal (worst condition) for design 45% Section - 8 Page 4 of 103

107 Description Total ash produced from both the units Bottom Ash (15%) Fly Ash (85%) 100% Indian coal 488 TPH 74 TPH 414 TPH The system envisages the following:- a) Continuous dry removal and disposal of bottom ash b) Continuous dry evacuation of fly ash c) Dry fly ash collection in silos of 24 hours aggregate storage capacity. d) Provision for intermittent wet disposal of fly ash and bottom ash Bottom Ash System The Bottom Ash Handling System is to extract, cool, grind and transport in a completely dry way, the hot bottom ash and the unburned carbon, which fall down into furnace ash hopper up to bottom ash storage silo. The Bottom Ash Handling System comprises of the following equipment: 1) Mechanical Expansion Joint 2) Bottom Ash Hopper with Hydraulic Bottom Doors 3) Dry Extractor/Cooler 4) Pre-Crusher 5) Primary Crusher & Hydraulic Pre-Crusher 6) Post cooler Conveyor 7) Bottom Ash Storage Silo 8) All necessary fittings, valves and etc Mechanical Expansion Joint The Mechanical Expansion Joint has the sealed connection between the boiler and the bottom ash hopper, whilst allowing for boiler expansion. The joint itself shall be composed of several layers of special fabric in order to obtain a high thermal insulation and mechanical strength combined with a great flexibility Bottom Ash Hopper with Hydraulic Bottom Doors The Bottom Ash Hopper shall be connected through the mechanical expansion joint to the boiler throat, directly connected to the dry extractor/cooler. The Section - 8 Page 5 of 103

108 external shell of the hopper shall be made of carbon steel made while the internal part shall be lined with insulation panels and refractory for protection against heat and abrasion. Visual inspection of the hopper will be possible through poke-holes installed in adequate positions, whereas adequate access for boiler maintenance is provided through man-hole and access door. The hinged type hopper bottom door, suspended on the hopper bottom part allows ash storage below the boiler. Their upper part shall be refractory lined for protection against contact with the hot ash. The bottom doors system shall operated with a hydraulic power unit. be By closing the bottom doors the hopper will allow ash accumulation above the closed bottom doors using the entire hopper volume for ash storage. This will assure, in case of downstream component failure, the necessary intervention time for removing the failure guaranteeing the maximum dependability so to prevent forced boiler outages. When maintenance intervention has been completed, the stored bottom ash shall be extracted, by opening the bottom doors sequentially (pair by pair), by the dry extractor/cooler Dry Extractor/Cooler The Dry Extractor/Cooler design shall be to withstand the arduous operating conditions under the boiler throat, characterized by high temperatures and shock impacts by large ash clinkers falling from the boiler. Its primary function shall be extract the ash from the boiler and cool it to a sufficiently low temperature that allows the discharge into the downstream processing equipment. The dry extractor / cooler shall be completely sealed, thus preventing any uncontrolled infiltration of air from the ambient and in the same time preventing any leakage of ash or gas to the outside. The external casing and the stainless steel belt shall be designed in order to allow the passage of any ash clinker that can pass through the boiler throat. The dry extractor/cooler shall be equipped with a Stainless Steel Belt which shall be supported by carrying idlers across its entire width, in order to withstand heavy mechanical impacts. All bearings shall be fitted outside the casing to protect them from heat and to allow easy maintenance. The belt speed shall be adjustable by means of an electric motor driven through frequency converter. This system has the function to receive and convey the ash falling from the Section - 8 Page 6 of 103

109 boiler up to its discharge chute directly onto a primary crusher for the ash size reduction. Inside the casing, under the stainless steel belt, a Scraper Conveyor shall be installed in order to clear the bottom floor of the casing from fines and dust. It consists of two lateral chains connected by scraper flights that sweep the accumulated dust over the extractor floor up to the head section of the dry extractor/cooler, where it is discharged onto a primary crusher Primary crusher & Hydraulic pre- Crusher The Primary Crusher, will be installed at the dry extractor/cooler discharging chute, shall be a single-roller crusher type. It shall be able to reduce the ash size down to a maximum of required level. Crushed ash will be fed to the downstream post cooler conveyor for further cooling and transportation. The single-roller crusher shall be designed to handle the largest possible range of friable materials. As ash falls onto the crusher, the rotating cam teeth shear and split the ash clinkers against an anvil plate. The crushed ash then drops through the clearance between the rotor and the anvil plate into the downstream equipment. As the cams rotate and mesh with the combing plate, crushed ash is efficiently cleared from the cams. Above the primary crusher a Hydraulic Pre-Crusher will be installed in order to break the oversize lumps falling down from the boiler and transported by the dry extractor / cooler. The pre-crusher will reduce the oversize ash lumps dimension in order to allow the correct operation of the primary crusher, preventing possible clinkers build up on the roller crusher which may interfere with correct system operation. At the discharge of the primary crusher the ash will pass through a Contact Cooler, whose aim will be to further cool the bottom ash before discharging into the Post Cooler conveyor Post cooler The Post cooler conveyor shall be based on the same mechanical concept of the dry extractor/cooler. It shall be a totally enclosed mechanical conveyor equipped with a steel belt. The function of the post cooler conveyor will be to further cool down the ash once crushed and transfer it to the bottom ash storage silo. Section - 8 Page 7 of 103

110 Bottom Ash Storage Silo The Bottom Ash Storage Silo receives the ash from the post cooler conveyor. The silo shall be made of carbon steel, closed on top and its filling will be done preventing undesired air leakages. The bottom ash storage silo will be provided with ash level control sensors, which are adapted for dusty and hot environment. The bottom ash storage silo will be provided with two outlets, both fitted with a vibrating feeder and a mixer unloader for wet ash discharge directly onto truck for further transportation to Ash Pond. There will be Two (02) silos for the collection of bottom ash, each of 1600 m 3 capacity for one day (24 hrs) storage of bottom ash generated Advantages of Dry type extraction system 1. High dependability and safety 2. No water related problems 3. By not using any water for the ash processing, a series of operational and environmental problems are eliminated by using this system a) No fresh water consumption and no waste water production b) No need for dewatering bins, ponds or waste water treatment c) No problems with environmental regulation regarding water pollution 4. Low operation and maintenance demand a) There is no relative motion in between ash and belt so no wear occur in the belt. b) Maintenance demand is very low and all operation is carried out with system in operation. c) Power consumption is very low, because no water has to move only dry ash. 5. Heat recovery from the ash to boiler a) Heat contained in the bottom ash is recovered by the cooling air before it flows up into the boiler. b) This heat recovery can contribute to increased boiler efficiency. 6. Delivery of dry ash a) After pulverization, dry bottom ash can be mixed with fly ash, leading to increased ash sales revenue and simple management. Section - 8 Page 8 of 103

111 In case of emergency bottom ash will be extracted through intermittently operating jet pump system, the jet pumps would convey the bottom ash slurry from water impounded bottom ash hopper to the slurry sump of the combined ash slurry disposal pump house. The GA scheme for bottom ash handling is enclosed as Drawing No: CCE ME Fly ash System Fly ash collected in various APH, Induct, ESP and Stack hoppers shall be extracted and conveyed to intermediate surge hopper automatically and sequentially by means of vacuum generated by mechanical exhauster and shall be transported to fly ash silos by means of pressure conveying system. Pneumatic conveying system shall be employed for extraction of fly ash from the electrostatic precipitator hoppers in dry form. Fly ash removal shall be completed in 5.5 hours for every eight hours shift. Incase of emergency fly ash will be extracted in wet form. The scheme for emergency ash disposal is enclosed as Drawing No: CCE ME Pneumatic Pressure Transport System The fly ash from the intermediate surge hopper, having effective storage capacity shall be conveyed to main silos by set of working pressure conveying vessels provided below ISH. Conveying compressors / blowers shall provide compressed air is provided for conveying. Suitable number of working conveying vessels shall be provided below each ISH, all-operating to achieve conveying rate. Two (2) nos. pressure-conveying streams per unit, both working has been considered. Four (04) nos Conveying air compressors / blowers per unit, three working ad one standby will be provided ESP cum Buffer Hopper Fluidizing Arrangement Three (3) Nos ESP hopper-fluidizing blowers (two working and one common standby per unit) each of adequate capacity with two nos of heaters will be provided. Section - 8 Page 9 of 103

112 To meet the instrument air requirement of various actuators, Bag Filters and vent Filters, an independent instrument air supply system has been considered. This would ensure reliable and efficient operation of the Ash Handling Plant. For this purpose, 2 nos of non-lubricated reciprocating compressors with 2 nos of Reactivated blower type Air Drying Plant (one working and one standby) is envisaged Fly Ash Collection and Disposal There will be Four (04) silos for the collection of fly ash, each of 1600 m 3 capacity for Twelve (12) hours storage of fly ash generated. Three (3) fluidising blowers with two heaters (both operating) have been considered, out of which two shall be working for each silo and one common standby Unloading & disposal system below silos a) Dry disposal system: Two (2) nos. dry unloading facility shall be provided below each silo. To unload dry fly ash into a closed tanker, telescopic chute type arrangement will be provided. Adequately rated oil free rotary screw type conveying Air compressors shall be provided to supply compressed air required for conveying fly ash from buffer tanks to fly ash silos. b) High Concentration Slurry density: HCSD System is envisaged for the disposing of fly ash collected in each ash silo. Fly ash from each silo shall be fed to the HCSD system through an ash mixer (rubber lined). Two outlets below each silo shall be provided with both feeding to dedicated HCSD stream provided for each silo. The dosing and mixing unit will create a pre set fly ash / water mixture and feed this into the ART (agitated retention tank). The control loop continuously monitors the density of the slurry and automatically provides for correction if required through the addition of water. The screens ensure any dried lumps of ash or trap material do not enter the mainline pump and pipeline. Section - 8 Page 10 of 103

113 The slurry is transferred to the installed mainline Piston diaphragm pumps via air-vessels. The Piston diaphragm pump will develop the pressure required to transfer the slurry to the other end of the discharging pipeline into the ash pond. 2 Nos (1W+1S) drain pumps shall be provided at the drain sump of fly ash silo area. The drain pumps shall be of vertical type Installation of FGD System Flue Gas Desulphurisation (FGD) system is necessary to capture the sulphur in the flue gas when the boiler is fired with high sulphur coal. High percentage of sulphur is observed in imported coal. Indian coal has very low sulphur and hence FGD system is not warranted. However, MOE&F while according environment clearance stipulate that space is to be kept in the layout for installing FGD system, if required, in future. There are two types of FGD system: Limestone based system Sea Water based F.G.D. system. Space is required for FGD system equipments and for the storage of limestone, a byproduct. The proposed 2 X 800 MW Power Project is a coastal power plant, hence sea water based FGD system will considered. The space requirement for F.G.D. limestone storage was deliberated and added in the land requirement. The space for limestone based FGD system for 2 X 800 MW is around 05 Acres. Flue gas desulphurization (FGD) system to be installed in order to meet the requirements of pollution control board. Fly Ash handling Scheme is enclosed in the Drawing No: CCE ME Ash Utilization The ash utilization is required to be carried out at all the coal based thermal power plants that are emitting ash that are under construction, renovation, modernization and those at the preliminary stage of investigation and infrastructure development within 100 km radial distance and if necessary, ash Section - 8 Page 11 of 103

114 utilization may also be carried out beyond 100 km radial distance. The important areas of ash utilization are indicated below: i) Building Sector for use in bricks, blocks, tiles, cement, concrete, plaster, etc. ii) Land reclamation, filling low lying areas, raising ground levels. iii) Roads, embankments, ash dykes, road blocks, kerb stones, etc. iv) Agriculture and wasteland area development. v) Hydro Sector, Irrigation, drains, water supply & drainage, lining of rivers, tributaries, canals, minors, sub-minors etc. vi) Mine filling. vii) Industrial applications & high value areas. viii) Roller compacted dams, pavements, roads etc. ix) Special use for ash e.g., collecting cenospheres from floating ash. All applications are primarily based on Research, design demonstration and confidence building in the use of fly ash based products Plant Water System The raw water requirement for the proposed power plant is estimated m 3 /hr and the same can be met from existing cooling tower forebay of NCTPS Stage II. The make-up water for cooling tower, boiler make up & other sweet water requirements are to be met from proposed desalination plant and Demineralized plant. The ~10 cumecs of excess water is available at the existing cooling water forebay of NCTPS Stage II which is located at ~5 kms away from the proposed site. Raw water would be conveyed through the underground conduits to the plant site. Closed circuit re-circulation type of cooling system using clarified water as make-up with Natural draft cooling towers has been proposed for power plant. The raw water requirement (sea water) details for the proposed 2 x 800 MW power plant are as follows: Section - 8 Page 12 of 103

115 S. No Description Values in m 3/ hr I DM Water requirement a. Make-up water in power 3% of 2 X 2600 m 3 /hr b. Make-up water for auxiliary boiler in power 3% of 1 x 70 m 3 /hr (for both unit) 2.1 c. Make up for Plate Heat Exchanger 4.0 d. Considering regeneration time of 4 hours the capacity of DM plant is worked out to x II Filtered Water requirement a. For DM Plant and Micro Filtration & RO requirement b. For cooling tower water makeup (sea water) d. For Service water & Miscellaneous e. Losses from SWRO & BWRO rejects f. Losses from Clarifier rejects Total Raw water requirement The water Balance Diagram for the power plant is attached in the drawing no: CCE ME Raw Water Treatment System The proposed Water Treatment plant is designed for raw water received from the source of sea water. The total raw water requirement considering sea water alone is estimated to m 3 / hr for the proposed 2 x 800 MW Power plant. Section - 8 Page 13 of 103

116 Capacity of the water treatment plant For Sea water Flocculator : 3 x 1500 m 3 /hr (3 x 33.33%) RSF : 2 x 1200 m 3 /hr (2 x 50%) SWRO : 2 x 1200 m 3 /hr (2 x 50%) MCF : 2 x 150 m 3 /hr (2 x 50%) BWRO : 2 x 150 m 3 /hr (2 x 50%) MB : 2 x 200 m 3 /hr (2 x 100%) Poly Dosing System Polymer solution is dosed by means of an electronic diaphragm type-dosing pump for flocculation. Flocculation is the agglomeration of destabilized particles into micro floc and later into bulky floc which can be settled. The introduction of reagent called a flocculant or a flocculant aid may promote the formation of the floc 1 x 100% vertical FRP tank with agitator and level switch and it s suitable for 24 hours continuous operation. 1 x 100% electrically operated & mechanically actuated dosing pump. The pump wetted parts shall be PP (Poly Propylene) construction Coagulant Dosing System Coagulation - flocculation processes facilitate the removal of suspended solids, turbidity and colloids. Suspended solids of sand and gravel of size greater than 1 mm settle rapidly in water. Clay-like material of the size of a few microns take time to settle; while colloids which refer to particle size in the sub-micron range cannot settle naturally and so the process of coagulation - flocculation brings about the settling of these substances to effect their removal. 1 x 100% vertical FRP tank with agitator and level switch and it s suitable for 24 hours continuous operation. 1 x 100% electrically operated & mechanically actuated dosing pump. The pump wetted parts shall be PP (Poly Propylene) construction. Section - 8 Page 14 of 103

117 Flash Mixer Flash Mixer to be designed with slow speed flash mixing mechanism with gear reduction gear box. The flash mixer shaft and the impeller shall be of SS316L with FRP coated. Sea water resistance painting considered for all motor rotating equipment and gear box surface. The flash mixer tank shall be of RCC in construction with marine grade epoxy painted internally. The capacity of the tank shall be for 2 minutes retention time of feed flow to be considered Flocculator Flocculator to be designed with slow speed mixing mechanism with reduction gear box, the mixer shaft and the impeller shall be of SS316L with FRP coated. Sea water resistance painting to be considered for all motor, rotating equipment and gear box surface The flocculator tank shall be of RCC in construction with marine grade epoxy painted internally. The capacity of the tank shall be for 15 minutes retention time of feed flow to be considered Clarified Water Storage Tank (CWST) One (1) no of m 3 capacity considering 12 hrs storage RCC-EP Construction of Clarified water storage tanks will be provided Rough Sand Feed Pumps Three (3) x 100% (2W+1S) no of Rough Sand Feed Pumps with motor on a common base frame Rough Sand Filter Two (2) x 100% (1W+1S) no of Rough Sand Filter (RSF) of MSRL construction with frontal pipe work and initial functional requirements with all valves and interconnecting piping is envisaged. The filtering media shall be graded sand and supported by pebbles & gravels. Surface velocity for designing shall be 12 m 3 /hr and minimum shell thickness of 6 mm. The MOC of Filter shall be MSRL with 4.5 mm thick rubber lining to be Section - 8 Page 15 of 103

118 provided. Supporting bed for the filter media shall be provided as required. Back washing shall be done by reversing the treatment flow manually. The inlet distribution system shall be designed to give uniform distribution of water over filter media. The under drain collection system shall be designed for uniform collection of filtered water & distribution of back wash water. All frontal Butter fly valves shall be of Duplex Steel / Ni+Al+Bz material of construction Fine Sand Filter Two (2) x 100% (1W+1S) no of Fine Sand Filter (FSF) of MSRL construction with frontal pipe work and initial functional requirements with all valves and interconnecting piping The filtering media shall be graded sand and supported by pebbles & gravels. Surface velocity for designing shall be 8 m/hr and minimum shell thickness of 6 mm. The MOC of Filter shall be MSRL with 4.5 mm thick rubber lining to be provided. Supporting bed for the filter media shall be provided as required. Back washing shall be done by reversing the treatment flow manually. The inlet distribution system shall be designed to give uniform distribution of water over filter media. The under drain collection system shall be designed for uniform collection of filtered water & distribution of back wash water Acid Dosing System The Acid will be dosed in-line by electronic diaphragm pumps. It will have one pump. The hypo chlorite solution is stored in an adequate capacity HDPE tank equipped with a level indicator, level switch and other accessories. 1 x 100% vertical FRP tank with level switch and it s suitable for 24 hours continuous operation. 1 x 100% electrically operated & mechanically actuated dosing pumps. The pump wetted parts shall be PP (Poly Propylene) construction. Section - 8 Page 16 of 103

119 Sodium Meta Bisulphate Dosing System To prevent any residual chlorine from entering the RO system and causing fouling of membrane a SMBS Dosing & ORP Analyser with auto dump valve is provided. In case the residual chlorine in water is high the auto dump valve will activate to prevent water from entering the system. 1 x 100% vertical FRP tank with agitator and level switch and it s suitable for 24 hours continuous operation. 1 x 100% electrically operated & mechanically actuated dosing pump. The pump wetted parts shall be PP (Poly Propylene) construction Anti-scalant Dosing System To reduce the scaling tendency of calcium and magnesium over RO membrane they are dosed with Anti-scalant to reduce the fouling of membranes. This will improve the life and efficiency of the membrane. Acid and anti-scalant dosing will prevent the fouling of the membrane due to high concentration of the salts in reject by inhibiting the activity of Low solubility salts like calcium and silica. 1 x 100% vertical FRP tank with agitator and level switch and it s suitable for 24 hours continuous operation. 1 x 100% electrically operated & mechanically actuated dosing pump. The pump wetted parts shall be PP (Poly Propylene) construction Micron Cartridge Unit 2 x 50% no of micron cartridge Vessel, houses the PP cartridge elements of 5 micron rating which remove micron size particles which otherwise will clog the R.O. Membranes High Pressure Pumps 3 x 50% (2W+1S) no of Centrifugal vertical / multi-stage type of pump in stainless steel construction is provided for feeding the water to R.O. System at high pressure. Necessary instruments like High & Low pressure switch, pressure gauges & necessary valves are provided for this system. Section - 8 Page 17 of 103

120 Energy Recovery Device (ERD) The ERD shall be designed in such a way to extract maximum pressure from the sea water RO reject pressure. The ERD may of Pressure Exchanger type or pelton wheel type. The material of construction shall be Duplex steel Sea Water Reverse Osmosis (SWRO) 2 x 50% SWRO system shall be completely skid mounted having a treatment capacity cater to Second pass RO feed water requirement and shall be operated thro PLC (Semi-automatic). The recovery of the plant shall not be less than 45%. RO membrane shall be DOW / Toray make only with SW 30HR-380 / TM sq. ft area with 32 mill spacer. RO membrane Avg. designed flux shall be < 13 Litres /Sq. Metre /Hour (LMH) and MOC of the Membrane shall be Polyamide and TFC in configuration Sea water RO system shall be designed for variable temperature from 25 C to 35 C. The high pressure pump for the desalination RO shall be selected considering the feed pressure requirement at 25 C. The guaranteed permeate TDS shall be < C Sea Water Reverse Osmosis Storage Tank One (1) no of 2000 m 3 capacity RCC-EP Construction of Sea Water RO Permeate storage tanks will be provided Micron Cartridge Feed Pumps Three (3) x 100% (2W+1S) no of Micron Cartridge Feed Pumps with motor on a common base frame is envisaged NaOH Dosing System 1 x 100% vertical FRP tank with agitator and level switch and it s suitable for 24 hours continuous operation. 1 x 100% electrically operated & mechanically actuated dosing pump. The pump wetted parts shall be PP (Poly Propylene) construction. Section - 8 Page 18 of 103

121 Micron Cartridge Unit 2 x 50% no of micron cartridge Vessel, houses the PP cartridge elements of 5 micron rating which remove micron size particles which otherwise will clog the R.O. Membranes High Pressure Pumps 3 x 50% (2W+1S) no of Centrifugal vertical / multi-stage type of pump in stainless steel construction is provided for feeding the water to BWRO System at high pressure. Necessary instruments like High & Low pressure switch, pressure gauges & necessary valves are provided for this system Brackish Water Reverse Osmosis 2 x 50% BWRO system shall be completely skid mounted having a treatment capacity cater to Second pass RO feed water requirement and shall be operated thro PLC (Semi-automatic). The recovery of the plant shall not be less than 85%. RO membrane shall be DOW / Toray make only with BW / TM sq. ft area with 32 mill spacer. RO membrane Avg. designed flux shall be < 28 Litres/Sq. Metre/Hour (LMH) and MOC of the Membrane shall be Polyamide and TFC in configuration De-Gasification Tower The water from R.O. Unit is further passed-through a 1 x 100% no of Degasser tower for removal of alkalinity present in raw water. It is a MSRL vertical pressure vessel, which is internally fitted with inlet distributor and a bottom collecting system. Externally, it is fitted with pipe work and isolation valves. This unit is filled with PP Pall Rings DG Water Transfer Pump 2 x 100% (1W+1S) no of Centrifugal type pump in SS construction is provided for feeding of water from the R.O. storage water tank to the MB units at the required flow rate and pressure of 3.5 Kg/Cm Mixed Bed Exchangers The treated water is further passed through the 2 x 100% no of (1W+1S) Mixed Bed Unit for polishing of treated water from RO Plant and further reduces the Section - 8 Page 19 of 103

122 conductivity of Boiler Feed Water. It is a MSRL vertical pressure vessel, which is internally fitted with inlet distributor and a bottom collecting system. Externally, it is fitted with frontal pipe work and isolation valves. This unit is charged with cation & anion resins. For Re-generation of mixed bed unit, HCl & NaOH are used to re-charge the resin once stipulated time. The unit is isolated for re-generation when the conductivity leakage goes beyond specified limit Regeneration of Cation Exchangers Resins Cation exchange resins shall be regenerated by hydrochloric acid Acid Measuring Tank for Mixed Bed Exchangers A vertical MSRL / FRP tank shall be provided. Acid measuring tank shall have enough capacity to store acid required for single regeneration plus 10% extra margin Regeneration of Anion Exchange Resins Anion exchange resins shall be regenerated by sodium hydroxide Caustic Dilution Tank for Mixed Bed Exchangers A vertical MS / FRP tank shall be provided. Caustic Dilution tank shall have enough capacity to store caustic required for single regeneration plus 10% extra margin. The time required for regeneration of each MB stream shall not exceed 3 to 4 hours Air Blowers for Mixed Bed Exchangers After regeneration of the resins, the two beds shall be mixed by blow of compressed air through the resin bed. 2 x 100% capacity air blower for mixed bed exchangers shall be provided ph Correction Dosing System The mixed bed water is further dosed with Morpholiene for increasing the ph to the required level. Two (2) no of 1 x 100% of ph correction dosing system is provided. 1 x 100% vertical FRP tank with agitator and level switch and it s suitable for 24 hours continuous operation. Section - 8 Page 20 of 103

123 1 x 100% electrically operated & mechanically actuated dosing pump. The pump wetted parts shall be PP (Poly Propylene) construction Chemical Cleaning System This system is provided for the removal of any type of fouling occurring in R.O. System. It consists of a HDPE chemical preparation tank, a centrifugal pump in SS construction & a separate micron cartridge filter (5 micron rating) with interconnecting pipe work & isolation valves. Necessary instruments like pressure gauge, flow indicator and a level indicator is provided. Depending upon the chemical responsible for membrane fouling, the cleaning chemical solution is prepared. This system consists of the following equipment: Chemical Preparation Tank This is a vertical, cylindrical storage tank of HDPE construction used for preparation of various cleaning chemicals depending upon the foul ant in the membranes. This is fitted with inlet / outlet, overflow / drain, pipe work with isolation valves. These units will have agitator drives through an adequately size motor Chemical Cleaning Pump A separate pump shall be provided for this purpose. Necessary suction and discharge pipe work with isolation valves are provided. This pump is used for recirculation of cleaning chemicals from tank to the R.O. System and back to tank Micron Cartridge Filter This micron cartridge filter housing is provided due to its requirement of compatibility with vigorous cleaning chemicals required to clean R.O. Membranes at varying ph from During R.O. Cleaning operation, cleaning chemical solution is first prepared in chemical tank as per specified instruction. This solution may contain suspended / un-dissolved impurities which need to be prevented from entering in R.O. System. This micron cartridge element is of 5 micron rating and prevents the impurities. Section - 8 Page 21 of 103

124 DM Water Tank Four (4) nos of 500 m 3 capacity Mild Steel Rubber Lined DM water storage tanks will be provided. The typical raw water system flow diagram is attached in the Drawing no: CCE ME Neutralized Waste Disposal Pumps The waste water from RSF, FSF back wash waste, SWRO reject, BWRO reject and MB regeneration will be led to neutralization pit (Under Ground) of required storage capacity, which is in RCC Construction. One (1) 100% neutralized waste disposal pumps shall be provided. Pumps shall be horizontal centrifugal type with materials. Recirculation of waste collected for neutralization and subsequent disposal shall be done by neutralized waste disposal pumps (Self priming pump) Station Effluent Treatment System The waste water treatment system shall be designed to collect waste water from all sources in the power plant and provide treatment to enable it to be reused in the power plant to achieve ZERO DISCHARGE. There will be one no. Effluent Treatment Plant having the size of 60 M x 60 M is envisaged inside the plant boundary. Oily water waste from transformer area, in the event of Fire spray, shall collect in a local pit in each unit. Oily water from transformer oil separator shall be transferred by 2 x 100% screw pumps per unit to an oily waste collection sump. Waste water from TG hall shall be collected in local pits in each unit. Oily water from TG hall shall be transferred 2 x 100% screw pumps per unit to an oily waste collection sump. Waste water from fuel oil area shall be shall be transferred 2 x 100% screw pumps per unit to oily waste collection sump. Above collected oily wastes in common collection sump shall be treated in a TPI separator. The clean water after treatment is transferred to central monitoring basin. The recovered oil is stored in barrel/tank for further Section - 8 Page 22 of 103

125 disposal manually. Sludge from TPI separators shall be collected in trolley for further disposal manually. The wash water wastes from boiler area shall be collected in a sump and shall be transferred by 2 x 100% centrifugal vertical pumps to waste water collection sump. The side stream filter back wash shall be transferred by 2 x 100% centrifugal vertical pumps to waste water collection sump. The Pre Treatment Plant filter back wash shall be transferred by 2 x 100% centrifugal vertical pumps to waste water collection sump. Above collected waste in waste water collection sump shall be treated in Lamella clarifiers or tube settlers to remove the suspended solids. The clean water after treatment shall be transferred to central monitoring basin. The sludge generated shall be further treated in 1 x 100% thickener. A dedicated chemical dosing system with tanks and 2 x 100% metering pumps common for lamella clarifier and thickener shall be provided. The sludge generated from the lamella clarifier and RO plant clarifier shall be collected in the sludge sump and shall be transferred to 2 x 5 m 3 /hr. centrifuges. The clear water generated shall be transferred to CMB and the cakes shall be manually removed. Regeneration waste from neutralization pit in DM Plant area and CPU plant shall be pumped by 2 x 100% pumps to central monitoring basin. Auxiliary steam condensate from the fuel tank heating line shall be collected in the fuel oil area oil collection pit. The water from central monitoring basin can be used as a make up to ash handling plant or horticulture with an emergency dump to ash pond. It may be noted that, various wastewater generated above are treated either in TPI separator/lamella clarifier/tube settler or transferred without any further treatment to central monitoring basin/other systems. The above system facility shall remove only oil and suspended solids up to the following limits: Suspended solids : 100 ppm max. Oil and grease : 20 ppm max. PH : 6.5 to 8.5 Waste Water Management Scheme is enclosed as Drawing No: CCE ME Section - 8 Page 23 of 103

126 8.1.4 Cooling Towers (CT) The CW system envisaged for the plant is re-circulating type system with One (1) no of Natural Draft Cooling tower per unit using clarified sea water as a make-up water. The cooling towers will discharge the recooled circulating water to CW pump house circulating water sumps. Number of cooling towers : One (01) no for each unit Type of cooling tower : Natural Draft Design inlet circulating water flow rate : 92,000 m 3 /hr per unit Cooling range of circulating water : 10 0 C Ambient wet-bulb temperature : 27 0 C (for CT design) Circulating water makeup : Clarified sea water Suitable arrangement for shock & continuous dozing of chlorine to curb organic growth and chemical dozing i.e. scale / corrosion inhibitor and biocide dozing for maintaining 1.3 COC for deliberating sea water. Condenser cooling water scheme is enclosed in the Drawing No: CCE ME Compressed Air Scheme The compressed air system is comprised of the instrument air system and the service air system. Instrument air is required for the various pneumatically operated valves and instruments in the power plant, while service air is required for general plant services. The compressed air system of the proposed station is conceived to have three plant air compressors (two working + one standby) each of 60 Nm 3 /min. capacity at 8 kg/cm 2 pressure for the unit and three (3) instrument air compressors (two working + one standby) of identical pressure and capacity for the station with desiccant type air drying plant air receivers. The plant air compressors are to be connected to a single header and would be provided with interconnection with instrument air receiver to improve availability. VFD (variable frequency drive) is envisaged in the compressed air system which is for controlling the rotational speed of an alternating current (AC) electric motor by controlling the frequency of the electrical power supplied to the motor. Section - 8 Page 24 of 103

127 The compressors are identical, oil free, screw compressors / centrifugal compressors and water-cooled type, driven by electric motor including intercoolers, after coolers, step up gearbox, silencer and other accessories. Compressors, after coolers and intercoolers shall be of water-cooled type and shall utilize clarified water for cooling purpose. The intake air filter and silencer, necessary gauges and all accessories and Instruments & controls required for a complete compressed air plant. Outlet of all the compressors is connected in one header. At a suitable location in the header, a control valve shall be provided such that IA consumption will get first priority under all conditions. The required IA shall be passed through air driers before conveying to consumption points. Two (2) nos (1W + 1S) Air Drying Plant at a working pressure of 8.0 Kg/Cm 2 (g) shall also be provided to supply moisture free air to instruments. Air-drying plant capacity shall be adequate for the IA requirement. Air Drying Plant shall be heat of Compression HOC type. Dew point of air at the outlet of ADP shall be 20 o C at atmospheric pressure. Six (6) nos of Air receivers, i.e., 2 nos. for IA system & 2 nos. for SA system near compressor house and 2 nos. unit air (IA) receivers in TG building of 10 M 3 capacity each shall be provided, designed and constructed in accordance with the requirement of the ASME unfired pressure vessel code Compressed Air Scheme is enclosed in the Drawing No: CCE ME Condensate Polishing Unit (CPU) The Condensate Polishing Plant (CPP) shall treat the condensate of the respective Turbine-Generator (TG) Units of the power station. The Condensate polishing Plant shall consists of one set of Condensate polishing Units (CPU) for each TG unit inside TG Building and a common regeneration system. Each CPU shall consist of Four (4) service vessels (Three working & one standby vessel) of 33.33% capacity for each TG Unit. The regeneration system shall be external and common to the CPU of both the TG units. For regeneration, resin from the exhausted exchanger vessel will be Section - 8 Page 25 of 103

128 transferred hydraulically to this facility. The exhausted resin charge will be cleaned, separated, regenerated, mixed and rinsed before being stored for the next use. The common influent and effluent headers of each CPU, will be connected to an automatic bypass line (s). On high pressure signal across the service vessel, the automatic control valve(s) in the bypass line(s) shall open, bypassing the service vessel(s). Make-up water to the turbine cycle will be added to the condenser hotwell as required. The influent quality during start up may deteriorate to: TDS ppb 2000 max Silica ppb 150 max Crud ppb 1000 max (mostly black iron oxide) Ventilation & Air-conditioning System Building space conditioning will be provided for personnel comfort and for maintaining required environmental conditions for equipment within the enclosed spaces. Building space conditioning will consist of the following air conditioning and ventilating systems Turbine Hall The Turbine Building will be provided with evaporative cooling and ventilated by ventilators located in the turbine room roof and in the building walls. Supply air system will be provided with evaporative cooling plant by a set of air washers of 2 x 50% capacity with cooling water coils (water supplied from an independent source). The system will include 2 x 50% capacity supply air fans, inlet louvers, bird screens, viscous filters, cooling coils, re-circulating water system with 2 x 100% circulating water pump sets, 2 bank spray nozzles & flooding nozzles, eliminator plates and masonry sump tank etc for supply and distribution of cooled air at various locations. The exhaust system will consist of roof extractors (for machine room); axial flow wall mounted exhaust fans with GI ducts, dampers, grilles and other accessories as necessary. The system will be designed to maintain close to ambient dry bulb temperature inside the building. Section - 8 Page 26 of 103

129 Various rooms of the power plant building such as cable spreader room, switchgear room, TG Hall etc will be ventilated by means of pressurized supply and exhaust fans suitably located Central / Main Control Room Air conditioning equipment will be provided for control equipment areas such as main control rooms, static excitation rooms, UPS rooms etc. The equipment will include air handling units and condensing units. The air handling units will consist of a fan section and cooling coil section and will be located in or near the control area. The air-cooled condensing units will include compressor, condenser coil, condenser fans and motors. The condensing units will be located outside the building on grade or on the roof. Redundant air conditioning will be provided for temperature sensitive, critical control equipment. Controls will be provided to manually start the standby air handling and condensing unit if the operating unit fails ESP control building (except control room) For ventilation of this building, ambient air will be drawn through unitary air filtration unit comprising fresh air intake louver, dry type filter and cooling coils conveying water [supplied from an independent source] and supplied to the space by means of centrifugal fans through ducting, grilles, etc. The supplied air will be exhausted through wall mounted gravity operated dampers to maintain higher over pressure (measurable) in mm water column to reduce dust and fine sand Miscellaneous Air Conditioned Areas Miscellaneous offices and control equipment rooms will be air conditioned using packaged air conditioning equipment Miscellaneous Ventilated Areas Ventilation of the miscellaneous areas and other buildings will be provided as required for equipment operation and personnel comfort. Toilet and battery areas will be provided with exhaust fans. Section - 8 Page 27 of 103

130 Other buildings Other areas such as DG set room, air compressor room A/C plant room etc will be ventilated by means of dry system comprising axial flow fan, dry filter wherever required, cowls, ducting etc. Inside dry bulb temperature is maintained lower than ambient by about 5 C. Fire dampers will be provided on ductwork routed through electrical installation areas. Ventilation system of respective areas will be suitably interlocked with fire detection system to minimize spreading of fire. The normal design criteria for the design of the ventilation system is to consider at least 10 air changes per hour for an effective volume of space 4 m from the floor level. In areas such as the machine room of the plant building TG bay, etc where the volumes handled are very large, the system is designed by providing limit load type backward curved centrifugal DIDW blowers/fans (mounted on suitable heavy duty vibration isolators) inside an acoustically insulated room with dedicated ductwork so that all the heat generated is removed and a temperature lower than the ambient is maintained. The system envisages maintaining a temperature of 5 C lower than the ambient temperature for providing comfortable working atmosphere Fuel Oil System The Fuel Oil System shall consist of light diesel oil system and heavy furnace oil system to the steam generator igniters. Light Diesel Oil (LDO) shall be used for initial start up while heavy Furnace Oil (LSHS/HPS/HFO Gr HV) shall be used for flame stabilization and during low load operation. It is proposed to source LDO / HFO from nearby IOCL / CPCL terminal at Manali / nearest depot through tankers. The scheme for Furnace oil System is enclosed in the Drawing No: CCE ME Light Diesel Oil System (LDO) The light oil unloading & pressurization pumps shall be located in the fuel oil pump house. A common suction header for all units shall be provided for all the light oil pumps. Oil pipe work is routed through duplex strainer to igniter of each unit located near the each unit Boiler front. The excess oil when not in use shall return Section - 8 Page 28 of 103

131 to header from the each unit Boiler front to light oil fuel storage tank. The light oil storage and supply system shall provide light oil at the pressures and capacities required by the unit steam generator igniter fuel system. The system shall be capable of supplying the light oil requirements of each steam generator during warm-up, main fuel ignition, and flame stabilization at low firing rates, emergency generator, and engine driven fire water pumps. Each light oil pump shall be adequately sized to provide the light oil requirements for a cold start of each of the steam generator. In addition, the light oil pump shall also be adequately sized to provide the light oil requirements of the emergency generator, and engine driven fire water pumps. Each light oil unloading pump shall be adequately sized to unload tankers in an 8 hour shift. Adequate space shall be provided for maintenance of all pumps. The oil storage tanks shall be provided with a containment dyke wall to hold the entire contents of the storage tanks. Drainage from the oil tanks shall be controlled by manual valve, with all releases to the oil/water separator Heavy Furnace Oil System (HFO) The heavy furnace oil unloading pumps for all units shall be located in the fuel oil house. A common suction header for all units shall be arranged to permit heavy fuel oil unloading from Railcars simultaneously. Reinforced flexible interlocked stainless steel construction hoses, complete with quick disconnect couplers, shall be provided to connect the heavy furnace oil delivery Railcars to the suction header. The unloading fuel oil pump sets shall discharge the fuel oil from the suction header to the heavy furnace oil storage tanks. System piping arrangement shall allow the heavy fuel oil to be pumped through the fuel oil unloading pumps, metered prior to its delivery to the storage tanks. The heavy furnace oil tanks shall be provided with steam coil heaters in the floor and suction heater at the tanks outlet nozzles. The heavy furnace oil storage tanks shall be located in a contained area. Containment shall be by reinforced concrete containment basin (dyke wall) around the tanks. Concrete paving shall be made in the unloading area to provide an oil-resistant surface. The unloading area shall be curbed and sloped so that any oil spills and/or rainfall runoff is trenched towards the oil water separator. The unloading area shall be arranged so that traffic shall Section - 8 Page 29 of 103

132 not be impeded on the main access roadway and shall be sized to allow simultaneous truck parking at each individual unloading station. The fuel oil transfer pumps mounted on fuel oil pressurizing skid (one per each unit) shall draw the fuel oil from the storage tanks (common for all units) and pump the oil upto each unit boiler front. The excess oil when not in use shall be returned to the oil storage tanks. The fuel oil pressurizing skids shall be located in the fuel pump house near the fuel oil storage tanks. A common suction header shall be provided from the fuel oil storage tanks to each unit fuel oil pressurizing skids. The pressurizing pumps shall supply fuel oil through the fuel oil discharge headers to the each unit steam generator flame stabilization system. The fuel oil storage and supply system shall provide fuel oil at the pressures and capacities required by the each unit steam generator fuel system. The system shall be capable of supplying the fuel oil requirements of the each unit steam generator during warm-up, main fuel ignition, and flame stabilization at low firing rates. Each unit fuel oil pressurizing pump shall be adequately sized to provide the fuel oil requirements for a cold start of each unit steam generator. The fuel oil unloading pump shall be adequately sized to unload 40 rail tankers in an 8 hour shift. Adequate space shall be provided in the pump house for maintenance of all pumps. The oil storage tanks shall be provided with a containment dyke wall to hold the entire contents of the storage tanks. Drainage from the oil tanks shall be controlled by manual valve, with all releases to the oil/water separator. Normal annual requirement would be based on statistical average of oil consumption of 1.0 ml of HFO per Kwh of power generation. 15 days of oil storage is considered adequate during trial operation. Total HFO storage capacity shall be designed based on these parameters Cranes and Hoisting Equipment In order to facilitate the handling of various equipments during erection and maintenance of the power plant, number of cranes and hoists will be required at various locations. Two (02) nos. 130/30 T Capacity EOT crane is envisaged in the T.G. Hall. Crane to be provided will be designed and manufactured as per IS-3177/IS-807. The cranes will be double box girder, M3 duty and indoor duty. Section - 8 Page 30 of 103

133 Full-length platform of anti skid-chequered plate shall be provided on both sides of cranes. Rope drums and gearboxes will be M.S. fabricated and stress relieved. Cross traverse and long travel wheels will be double flanged with minimum hardness of BHN. Wheels will be provided with anti - friction bearings. All the drives will be provided with Electro hydraulic thruster brakes. Main motors of all the motions will be slip-ring induction / squirrel cage type. Micro speed arrangement will be provided on all motions with planetary gear and pony motor arrangement or with the help of VVVF drive and this arrangement will achieve 10% speed of main speed. Slip-ring motors used will be totally enclosed, Fan cooled, with Class B/F insulated, with degree of protection of all the motors shall be as IP-54. Crane will be controlled both from operator s cabin and pendent push button station. M.S. angle type down shop lead conductors will be provided for the power supply to cranes. Power supply to crab will be through flexible trailing cable arrangement. Suitable limit switches will be provided for hoists, cross traverse and long travel motions. CW Pump House One (1) number double girder EOT crane of required capacity has been envisaged. Span & lift of the crane shall suit the layout requirement. Crane shall be of indoor duty class II. Crane shall be provided with one side full span length working platform and other side with two short working platforms. Other main features of the cranes will be similar to TG Hall EOT crane except creep speed shall be provided only on hoisting arrangement. Other cranes to be provided in the power house shall be as specified below:- Miscellaneous Cranes Single girder EOT / HOT crane with capacity and span as required have been envisaged in the following areas. Crane to be provided shall be indoor type; M3 duty. The speed of the crane will be as per the manufacturer s standard practice. Work shop Building Air compressor Building Fire Water Pump House Raw Water pump house CW Blow-Down pump house Section - 8 Page 31 of 103

134 Electric Wire Rope Hoist Electric wire rope of required capacity will be provided as required in the following areas. The hoists will be pendent push operated and conform to IS: Motors will be of high torque, squirrel cage induction type with enclosure as totally enclosed type and degree of protection as IP-54. A/C Plant Room ACW / DMCW Pump House in Boiler Area Vacuum Pump Motor Handling Butterfly Valve Handling Control Fluid Room Chain Pulley Block with Trolley Manually operated chain pulley block with travelling trolley shall be provided in Central Lube Oil System Room, Air Washer Room and / or in other areas as required to meet the lifting requirement such as capacity, headroom and lift. The chain pulley block shall have self-braking system of holding the load at any position. Chain pulley block shall have helical or worm gear. The hook provided shall conform to IS: Other cranes/hoists of suitable capacity have been considered for lifting/handling of equipment in other areas such as steam generator auxiliaries, ESP, pump houses, coal handling plant, water treatment plant, ash handling plant, compressors, work shop, chlorination plant and miscellaneous pumps. Hoists/cranes of 3 tons and above/lift of 20 mtr or above will be electrically operated Hydrogen Generation Plant The Hydrogen Generation Plant shall be of Bi Polar design only having 2 streams (2 x 50 %) each of 10 Nm 3 /hr capacity of H 2 Gas Generation is envisaged to meet the generator cooling requirements of both units. The approx. hydrogen gas requirement for one unit will be about 150 Nm 3 /day. The normal hydrogen gas requirement for one unit will be about 30 Nm 3 /day. Approximately 300 Nos. of hydrogen cylinders, each of capacity 6 Nm 3, will be provided for hydrogen gas storage per unit, which will be used for normal supply of gas for make up and filling up of generators. Section - 8 Page 32 of 103

135 Carbon dioxide is required for purging the hydrogen and air during shut down and start-up respectively. About 50 Nos of CO 2 cylinders of each 8.85 Nm 3 capacity will be stored at site Fire Protection System For protection against fire, all yard equipment and plant equipment will be protected by a combination of hydrant system; automatic sprinkler spray system (emulsifier system); fixed foam system for oil handling areas; automatic high velocity and medium velocity sprinkler spray system; auto-modular inert gas based system for control rooms apart from portable and mobile fire extinguishers located at strategic areas of plant buildings and adequate Passive Fire Protection measures. The systems will be designed as per the recommendations of NFPA or approved equals in accordance with the Tariff Advisory Committee of the Insurance Association of India stipulations. Adequate separating distances will be maintained between different process blocks and hazardous equipment. To prevent fire from spreading through ventilation & air conditioning ducts, dampers with auto closing arrangements will be provided at appropriate locations. Fire water pumps are installed in the filtered water pump house. In the filtered water storage tank water will be stored as dedicated dead storage for meeting fire water requirement in exigencies. The details of system are as follows:- The hydrant system underground pipes shall be CIDF Pipes for mains and pipes. Two (1W+1S) electric motor driven fire water pump sets of adequate capacity having 88 MWC head along with one (1) identical capacity & head diesel engine driven backup fire water pumps of identical capacity will provided for hydrant and sprinkler system in addition to two (2) Jockey pump sets having adequate capacity and 88 MWC which would be brought to operation automatically when hydrant pressure drops indications are received. In addition to these pump sets, other auxiliaries for the fire protection system such as hydro-pneumatic tanks, compressors, pipe work, valves etc will be provided as required. The hydrant system will feed pressurized water to hydrant valves located throughout the plant and also at strategic locations within the power house. Section - 8 Page 33 of 103

136 Automatic high velocity sprinkler spray protection system will be provided for Generator transformers; Unit auxiliary transformers; Station service transformers; and Turbine oil storage tanks. Automatic medium velocity sprinkler protection system actuated by heat detectors strategically located will be provided for cable galleries and coal handling areas such as coal conveyors, transfer points, crusher houses etc. Fuel oil tanks in the fuel oil farm area will be provided with spray water system as well as fixed foam mechanical system to extinguish accidental fires in tanks as well as outside in the dyke. Automatic inert gas based flooding type extinguishing system will be provided for unit control room, areas independently apart from the provision of detection and fire alarm system in that area. Suitable fire detection system will also be provided at cable vault rooms, unit control rooms and other MCC rooms etc to detect outbreak of fire at an early stage. Adequate number of fire hydrant points will be distributed through out the plant building, service building, coal handling plant, ash handling plant and other areas along with fire hoses fitted with couplings and nozzles and kept in the hose boxes. In addition to the above facilities, adequate number of manual call points; as well as portable and mobile (wheel mounted) fire extinguishers of foam type; chemical type; and carbon-dioxide type or dry chemical powder will be provided at suitable locations throughout the plant area to meet NFPA code as well as Tariff Advisory Committee stipulations. And also the following systems are envisaged as an additional requirement. Self Contained BA sets Fire suit Special purpose spray nozzles, Foam Portable Petrol engine driven fire water pump These extinguishers may be used during the early stages of fire to prevent from spreading. Fire Protection Scheme is enclosed in the Drawing No: CCE ME Section - 8 Page 34 of 103

137 Elevators Two (02) nos of elevators, each having 1800 kg capacity passenger cum goods elevator for each boiler will be provided connecting various boiler floors and power plant building floors. One no. of passenger cum goods elevator of 800 kg capacity will be provided in ESP. One no. of freight cum passenger elevator of 1500 kg capacity will be provided in TG hall area. One (1) No Rack and Pinion type stack elevator shall be provided for double flue chimney to facilitate the movement of maintenance personnel to different levels of chimney. The capacity of stack elevator will be 400 Kg Work Shop A mechanical workshop will be provided for the day to day maintenance of mechanical equipment of the plant. Suggested list of workshop equipment / machines will be furnished during the detailed engineering stage Environmental Lab An environmental lab will be provided for measurement of climatic data and other measurement as per pollution control norms. A list of suggested equipment will be furnished during the detailed engineering stage. Section - 8 Page 35 of 103

138 8.2.0 Electrical Systems Basic Design Concept For designing the various electrical systems and equipment the following basic concepts will be applicable: a) Ambient temperature The design ambient air temperature will be 50 0 C. b) Voltage levels Voltage levels in the proposed plant will be 400 KV for Interconnection with grid, 27 KV for 800 MW generation. Large motors above 1500 KW, like BFP, ID, PA and supply feeders to Transformer shall be connected in 11 kv Switchgear. Motors 1500 KW and below up to 200 KW shall be connected in 3.3 kv switch gear. Auxiliary motors of 200 KW and below shall be fed in LT Switch gear. Single phase AC motors will not be used except in very special cases of low power for which panel mounted 415/240 volt transformers will be used. For 110 volt AC control supply, if used, separate panel mounted 415/110 volts transformers will also be used. 220V DC system will be used for control and supervision of the switchyard equipment and 48 V DC System for PLCC system c) Variations: Voltage variation will be ±10%, frequency variation shall be +3%& -5% and combined voltage and frequency variation will be ±10%. d) Fault levels: Fault levels for the various voltage systems shall be as under 400 kv 40 KA for 3 Sec. 11 kv 40 KA for 3 Sec. 3.3 kv 40 KA for 3 Sec. 415 volt 50 KA for 1 Sec. 220 volts D.C 25 KA for 1 Sec e) Basic Impulse level: The basic impulse levels will be 1425 KV p for 400 KV, 75 KV p for 11KV System and 45 KV p for 3.3 kv system. Section - 8 Page 36 of 103

139 f) Control and Protection Controls will be micro-processor based and centralized in a central control room Power Evacuation Transmission Interconnection Three sets of double circuit, 400 kv transmission lines proposed for the interconnection from power station switchyard up to the following 400 kv SS available in and around the project site for evacuation of about 1600 MW power from the proposed generating power plant. Sunguvar chattram Alamathy North TPS Stage II Thiruvalam Vallur TPS Sriperumpudur One 400 kv GIS switchyard will be constructed in the proposed power plant for evacuation of power through above transmission lines KV GIS Switchyard A 400 kv indoor Switchyard (Gas Insulated Sub-station) has been envisaged for evacuation of generated power through generator transformers from the proposed power plant. This switchyard will be located in an area separated from the main power house building and will be surrounded by a fence. 400 kv indoor switchyard will be designed with one and half breaker Scheme. The switchyard will be provided with the following fully equipped bays: 2 - Generator transformer bays kv outgoing feeder bays kv outgoing bays for future. 1 - Station transformer Bay 2 Reactor bays Section - 8 Page 37 of 103

140 a) Two Generator transformers / one stand by transformer / two reactors bay modules, each comprising of Three nos. of 3 phase SF6 insulated circuit breaker complete with operating mechanism. Multi ratio, multi core single phase current transformers. 3 phase, single pole group operated isolator switches, complete with manual and motor driven operating mechanism. 3 phase, single pole group operated safety ground switches, complete with manual and motor driven operating mechanism. Three EMVT or capacitive type voltage transformers, inside the GIS Compartment. Three outdoor type surge arrestors Three 1 phase SF6 Ducts and SF6 to air bushings for outdoor circuit termination. GIS duct with gas monitoring devices, barriers, pressure switches etc as required. Bay marshalling boxes, Local Control panels. b) Eight 400 kv transmission line circuit breaker bay modules, each comprising of 3 phase SF6 insulated circuit breaker complete with operating mechanism. Multi core single phase current transformers. 3 phase, single pole group operated isolator switches, complete with manual and motor driven operating mechanism. 3 phase, single pole group operated safety ground switches, complete with manual and motor driven operating mechanism. One 3 phase single pole, high speed fault making ground switch, complete with manual and motor driven operating mechanism. Three 1 phase SF6 Ducts and SF6 to air bushings for outdoor circuit termination. Two Outdoor line Traps Three Outdoor CVT s suitable for carrier communication. The CVT s shall be provided with a common marshalling box. Three Outdoor type surge arrestors. GIS duct with gas monitoring devices, barriers, pressure switches etc as required. Section - 8 Page 38 of 103

141 Bay marshalling boxes, Local Control panels The station has 400 kv voltage levels for transmission. C) The 400kV GIS switchyard shall have bays & bus-configuration as indicated below:- The 400KV switchyard shall have following statutory clearances: Maximum System Voltage : 420KV Phase- to- Earth : 3500mm Phase- to- Phase : 4100mm (Conductor Conductor) Sectional Clearance : 6500mm Ground Clearance : 8000mm Switchyard Control Room The control, monitoring and operation of the 400 kv switchyard will be through SCADA in the Switchyard Control Room. The switchyard will have its own Control Building for accommodating SCADA system equipment and transmission Line Protection panels and other Switchyard auxiliary equipment. However SCADA shall be interconnected to power plant main DCS through serial link (Fibre optic cables) for monitoring purpose. Separate room will be provided in the switchyard control room to accommodate batteries for 220 V DC System for control and supervision of the switchyard equipment and 48 V DC System for PLCC system. Separate room will be provided for Tariff Metering Panels. Key Single Line Diagram of Power Plant is enclosed as Drawing No: CCE EL Power Transformers Generator Step-Up Transformer The Generator transformer for each 800 MW unit is of Three Nos of single phase, 50HZ, 420/ 3 / 27/ 3 KV, YNd1, each 320/256/192 MVA, OFAF/ONAF/ONAN cooled oil immersed outdoor transformer. Generator transformer will be provided with OFF Circuit Tap Changer (OCTC) having tap change range of ±5% in steps of 2.5% on HV side. Transformers will be provided with requisite protection devices and accessories. One (1) single phase transformer of above capacity shall be kept as spare for ready replacement in the event of failure of any Section - 8 Page 39 of 103

142 transformer. Partition wall will be built between transformers.. Burnt oil pit will be built for transformers Unit Transformer (UT) Two (2) numbers of Unit transformers for each 800 MW unit are envisaged. Each Unit Transformer shall be of Three phase, 27kV/11.5 kv, 70 MVA, Dyn 11 ONAN cooled oil immersed outdoor type. Unit transformers will be provided with ON Load Tap Changer (OLTC) having tap change range of ±5% in steps of 2.5%. Transformers will be provided with requisite protection devices and accessories. Start up power for the unit shall be availed from grid through Generator transformer and Unit transformers by back feeding, keeping GCB in open position. Once unit is started and synchronized at GCB, unit auxiliary power will be fed from the TG. Providing Generator Circuit Breaker (GCB) at generator terminal voltage offer many advantage when compared with the unit connection and start-up station transformer such as; Lower first (initial) cost, simplified operational procedure, better fault protection, Considerably more secured synchronization at the generator voltage with the help of GCB than synchronization with a high-voltage circuit breaker (CB), less space requirement in 400 KV switchyard etc Stand by Transformer The Stand by Transformer will be of three phase, Two winding 420/11.5 kv, 70MVA, ONAN cooled oil immersed outdoor type. The transformers will be provided with On-load tap changer (OLTC) with ±10% in steps of 1.25% tapping on the HV side. Stand by transformers will be rated to meet the total loads required to run the power plant at MCR condition in case of failure of UT. The Transformer is Star / Star (YNyn0) connected. LV sides will be grounded through resistor limiting fault current to about 400 Amps Service Transformers Unit Auxiliary Transformers(UAT) Required Nos. of 11 kv / 3.5 kv adequately rated Unit Auxiliary transformers for supplying the H.T Motors rated 3.3 kv, 1500 KW and below up to 200 KW. The transformers are sized on the basis of 2 x 100% rating. These transformers will be provided with off circuit tap changer ± 5% in steps of 2.5%. The Unit Section - 8 Page 40 of 103

143 auxiliary transformers will be DYn1 connected and the neutral will be effectively grounded. These transformers shall be dry type suitable for indoor location LT Auxiliary Transformers Required Nos. of 11 kv / 433 V adequately rated transformers for supplying the unit loads and station low voltage loads will be provided. The transformers are sized on the basis of 2 x 100% rating. These transformers will be provided with off circuit tap changer ± 5% in steps of 2.5%. The auxiliary transformers will be DYn11 connected and the neutral will be effectively grounded. These transformers shall be dry type suitable for indoor location Switchgears 11 kv Switchgear 11 kv switchgear, as shown in one-line diagram, will be metal clad vertical single front draw-out type for indoor installation. Degree of protection shall be IP4X. Breakers will be either SF6 or vacuum type, suitable for a rupturing capacity of 40 KA, closing and opening time not exceeding 5 and 4 cycles respectively. The breakers will be trip-free with anti-pumping device and operating mechanism of stored energy type with DC motor operated charging of spring. Busbar will be SPBD type. Busbar will be Heat shrinkable PVC sheathed shroud-jointed and temperature of the busbar at 50 0 C ambient will be limited to 90 0 C. 3.3 kv Switchgear The 3.3 kv systems will be non-effectively earthed. The switchgear will be rated for a symmetrical fault current of 40 KA for 1 sec. The 3.3KV switch gear will comprise draw-out type Vacuum/SF6 circuit breakers housed in indoor, metal-clad cubicles and will cater to all 3.3 kv motors. The switch gear will be equipped with control, protection, interlock and metering features as required. H.T Motor feeders will be provided with fuses and vacuum contactors. Section - 8 Page 41 of 103

144 415 Volt Switchgear 415 volt switchgear, as shown in the one line diagram, will be metal clad vertical single/double front draw- out type IP54 enclosure class for indoor installation. Panels will be arranged for bottom entry of cables, as required. The incomers, ties and motors of 110 KW and above will be controlled by circuit breakers. Other feeders will be controlled by switch fuse/contactor for motors and switch fuse for feeders. Circuit breakers will be of air-break type. The rupturing capacity will be 50 KA. For LT motors upto 7.5 KW motor protection circuit breaker will be provided. From 7.5 KW 110 KW motors electronic motor protection relay will be provided. Above 110KW motors numerical motor protection relay will be provided. Busbar shall be PVC sleeved jointed shrouded and rated for 2500 Amps, or as required, with total temperature limited to 90 o C at 50 o C ambient Electric Drives Electrical drives will be 3 phase 50 cycle squirrel cage energy efficient type - 1 induction motors operating at nominal voltages of V and 415 V Motors will be of high power factor (at least 0.85 for large motors), F class insulation, IP55 enclosure class (with canopy for vertical outdoor motors), designed for direct-on-line starting with as low starting current as possible. Starting current for boiler feed pumps, and CW pumps shall not exceed 6.0 times (with no positive tolerance) the full load current. Motor rating will be at least 1.15 times the consumption at the duty point of the driven equipment. Motors will be capable of starting and accelerating to full speed at 80% of the nominal voltage. For BFP pump the motor shall be capable of starting at 70% of Nominal voltage, and will be capable of either two starts in quick succession with third start after 5 minutes. In cold condition or two start at 15 minutes intervals in hot condition, both cases with voltage and frequency variation limits. Motors will also be capable of restarting under full load after a momentary loss of voltage with the possibility of application of a total of 150% nominal voltage. Section - 8 Page 42 of 103

145 Motor torque characteristic will be such as to ensure smooth and rapid starting and acceleration of the driven equipment. Motors will be provided with suitable heating arrangement while at standstill Protection Electrical protection proposed for the various equipments shall be generally as indicated below: Generator and Generator Transformer Generator: a) Differential (87G) b) Inter-turn fault (95) c) Stator earth fault (64G) d) Loss of excitation (40) e) Negative sequence current (46) f) Reverse power (32) g) Low forward power (37) h) Rotor earth fault (64R) i) Over-voltage (59) j) Under-voltage (27) k) Generator pole Slipping (98) l) Under frequency (81U) m) Over Frequency (81O) n) Voltage balance (60) o) Overload (50) p) Backup impedance (21G) q) Inverse time over current (51) r) Thermal Over load(49) s) Over fluxing(99) t) Dead Machine Protection(50GDM) u) Rate of Change of Frequency (df/dt) - Stage-1 v) Rate of Change of Frequency (df/dt) - Stage-2 Generator Transformer: a) Generator, Generator transformer, UT overall differential protection (87GT) Section - 8 Page 43 of 103

146 b) Generator transformer Backup Earth Fault Protection (51NGT) c) Generator transformer Differential Protection (87T) d) HV Restricted Earth Fault Protection (64RGT) e) Vector surge relay (78) f) Over fluxing Relay g) Buchholz Relay h) Winding Temperature i) Oil Temperature j) Pressure Relief Device operation k) Master Trip Relay (86) l) Tripping relays for protection devices of Generator Transformer (GT) and 63X / 49X for multiplying the contacts of protections. For trip function (63X1/49X1) GT buchholz II stage (63TX) GT winding temperature very high (49 WTX) GT oil temperature very high (49 OTX) GT pressure relief device operated (63 PTX) GT fire protection trip (FRTX) For annunciation function (63x2/49x2) GT Buchholz I stage (63AX) GT winding temperature high (49 WAX) GT oil temperature high (490AX) GT oil level low (OLAX) Cooler supply failure Cooler trouble Unit Transformer Protection a) Unit Transformer differential protection (87 UT) b) Unit Transformer Backup earth fault protection on the LV side (51NUT) c) HV inverse time Over current Protection (51UT) d) HV Phase Instantaneous Over Current (50UT) e) Restricted Earth Fault Protection (64RUT) f) Buchholz Relay g) Winding Temperature h) Oil Temperature Section - 8 Page 44 of 103

147 i) Pressure Relief Device operation j) OCTC surge protection. k) Master Trip Relay (86) l) Tripping relays for protection devices of Unit Transformer (UT) and 63X / 49X for multiplying the contacts of protections. For trip function (63X1/49X1) UT buchholz II stage (63TX) UT winding temperature very high (49 WTX) UT oil temperature very high (49 OTX) UT pressure relief device operated (63 PTX) UT fire protection trip (FRTX) For annunciation function (63x2/49x2) UT Buchholz I stage (63AX) UT winding temperature high (49 WAX) UT oil temperature high (490AX) UT oil level low (OLAX) Cooler supply failure Cooler trouble Stand by Transformer Protection The transformer protection system shall be provided with the following protective devices:- a) Differential (87T) b) Restricted earth fault (64REF) for HV and LV separately c) Back up Earth Fault protection (51NT) for HV and LV separately. d) Over fluxing (99) e) Transformer Buchholz (63) f) OLTC surge protection g) High winding temperature h) High oil temperature i) Pressure relief device operation. j) Master Trip Relay(86) k) Tripping relays for protection devices of Station Transformer (ST) and 63X / 49X for multiplying the contacts of protections a) For trip function (63X1/49X1) Section - 8 Page 45 of 103

148 ST buchholz II stage (63TX) ST winding temperature very high (49 WTX) ST oil temperature very high (49 OTX) ST pressure relief device operated (63 PTX) ST fire protection trip (FRTX) b) For annunciation function (63x2/49x2) ST Buchholz I stage (63AX) ST winding temperature high (49 WAX) ST oil temperature high (490AX) ST oil level low (OLAX) Cooler supply failure Cooler trouble Unit Auxiliary & LT Auxiliary Transformer Protection For Unit Auxiliary & LT Auxiliary Transformer (oil filled) protection system shall be provided with following protective devices a) Over current relay(50/51) b) Earth Fault Relay(50N/51N) c) Restricted Earth Fault Protection (64R) d) Standby Earth Fault(51NT) e) Tripping relays for protection devices of Distribution Transformer and 63X / 49X for multiplying the contacts of protections. For trip function (63X1/49X1) Buchholz II stage (63TX) Winding temperature very high (49 WTX) Pressure relief device operated (63 PTX) Fire protection trip (FRTX) For annunciation function (63x2/49x2) Buchholz I stage (63AX) Winding temperature high (49 WAX) For Dry type transformer the protective devices shall be as above with modification. Section - 8 Page 46 of 103

149 8.2.7 HT switchgear Incoming (Source) Breakers Each incoming (source) breaker shall be provided with numerical feeder management type devices. These devices shall be multi-element type or multifunction devices comprising of the following protective elements:- a) Over current (50/51) for phase fault with timer (2) b) Over current (50N/ 51N) for earth fault with timer (2) c) Standby earth fault (51NT) (for incomer from transformer only) d) Restricted earth fault (64) (for incomer from transformer only) e) Under voltage with time delay (27) f) VT fuse failure Tie Circuit Breaker Each tie-breaker shall be provided with: One multifunctional relay comprising of following protective elements Over current (50/ 51) for phase fault with timer (2) Over current (50N/ 51N) for earth fault with timer (2) Under voltage with time delay (27) VT fuse failure One numerical synchronizing check relay, if applicable, complete with guard relay and hardwires Motor Feeder Each motor feeder shall be provided with: One numerical Motor Protection Relays to detect and take appropriate action against the following: Thermal over load (49) Phase fault (50) Unbalance (-Ve seq.)(46) Locked rotor (50LR) Numerical Differential protection (87) for motor rated above 1000 kw rating Section - 8 Page 47 of 103

150 8.2.8 LT Switchgear Volt PCC The minimum protections to be provided for different types of circuits are listed below: a) Incoming Feeder: Numerical O/C relays (50/51) for phase fault with timer (2) O/C relay (50N/51N) for Earth fault with timer (2). Under voltage relay (27) b) Outgoing Bkr. Feeder: Numerical O/C relays (50/51) for phase fault with timer (2) O/C relay (50N/51N) for Earth fault with timer (2). Apart from protection relays, each electrically operated breaker shall be provided with antipumping (94), trip annunciation (30), lockout (86), lockout supervision (95) and trip supervision (74) relays. Lockout relay shall be hand reset type. Fuse monitoring relay (98) shall be provided on the secondary side of voltage transformer to monitor fuses Volt MCC & DB The minimum protections to be provided for different types of circuits are listed below: a) Incoming Feeder: Numerical O/C relays (50/51) for phase fault with timer (2) O/C relay (50N/51N) for Earth fault with timer (2). Under voltage relay (27) b) Outgoing motor Feeder: Numerical O/C relays (50/51) for phase fault with timer (2) O/C relay (50N/51N) for Earth fault with timer (2). c) Contactor operated unidirectional motor feeders Short circuit protection by HRC fuses. Motor protection circuit breakers Adjustable time delay earth fault relay operated from zero sequence CTs for motor rated 75kW and only above. Section - 8 Page 48 of 103

151 d) Contactor operated valves/ damper feeders Short circuit by HRC fuse Motor protection circuit breakers e) Switch fuse feeders protected by HRC fuses Apart from protection relays, each electrically operated breaker shall be provided with antipumping (94), trip annunciation (30), lockout (86), lockout supervision (95) and trip supervision (74) relays. Lockout relay shall be hand reset type. Fuse monitoring relay (98) shall be provided on the secondary side of voltage transformer to monitor fuses. DC system: Insulation Monitoring Under voltage (27) or no volt relay. Static microprocessor based relays will be provided as far as possible. All tripping relays will be suitable for operation from 65% to 130% of control supply voltage kv Switchyard The protective relays shall be numerical type. Relays shall have communicable port for interfacing with SCADA. The functionality of relays for different kinds of feeder will be as follows: Outgoing Feeder a) 21 : Distance Protection b) 50/50N : Inverse time over current and earth fault c) 51/51N : IDMT phase over current and earth fault d) 50 LBB : Local Breaker Back up e) 87B : Bus Differential Protection kv GT breaker a) 87 GT : Overall Differential protection of GT b) 87T : Generator Transformer Differential Protection c) 64RGT : GT Restricted Earth Fault Protection d) 99GT : Over Fluxing Protection e) 50/51 : Instantaneous & IDMT phase over current f) 51N : Inverse time Earth fault Section - 8 Page 49 of 103

152 g) 87B : Bus differential protection h) 67 : Directional Phase Over current i) 67N : Directional Earth fault j) 50LBB : Local Breaker Back up Line Reactor a) 87 R : Differential protection relay for Reactor b) 50/51 : Instantaneous & IDMT phase over current c) 51N : Inverse time Earth fault d) 50LBB : Local Breaker Back up e) 21R : Back Impedance Relay Control Room There will be a centralized control room at the operating floor of steam turbine generator building in which control panels for the steam generator, steam turbine and generator, auxiliary power supply, will be housed. This will also house the Data Acquisition System equipment and fire alarm control panel. Control panels will be a combination of upright panels and separately mounted control desks with TFT. 400 kv Switchyard controls will be provided in the switchyard control room. Switchyard control and relay panels, SCADA system, DC system, PLCC equipment etc as detailed in previous/subsequent Paragraphs shall be accommodated in this control room DC System V DC system DC system will be for the control of generating units and control of plant auxiliary system and switchyard. DC system will be redundant type. A separate DC System is considered for Each Unit. The system will comprise 2 x 100% duty batteries each with float and boost chargers and DC distribution boards using MCCB in incomer circuits and switch fuse units in other feeders. DC system will generally supply for the following a) Emergency Lube Oil Pump, Jacking Oil Pump, etc b) Emergency Lighting (DC) c) Switchgear Control Section - 8 Page 50 of 103

153 V DC System A separate 24 V DC System is considered for each Unit, comprising battery, battery charger and DC distribution board shall be provided to cater the requirement of DDCMIS system cubicles, cards and transmitters etc V DC System A separate 48 V DC System is considered for Switchyard, comprising battery, battery charger and DC distribution board shall be provided to cater the requirement of PLCC system Uninterruptible power supply Redundant an uninterrupted power supply (UPS) system would be provided to cater to 240V AC, single phase, 50 Hz, 2 wire power supply requirements of instrumentation and control systems viz. man-machine interface equipment, analyzers, receiver instruments of each units, PA & EPBAX system etc. Separate UPS of sufficient capacity shall be provided for off site PLC system Power and Control Cables Power cables (AC and DC) will be aluminum conductor, stranded, XLPE insulated, screened, armoured and FRLS sheathed. Control cables will be 1100 volt grade multi-core, stranded, copper conductor, PVC insulated PVC sheathed, armoured and overall PVC/FRLS sheathed with minimum 2.5 mm 2 conductor size. Special cables will be used wherever so required for special applications Grounding & Lightning Protection The system grounding envisages generator neutral earthing through secondary resistance loaded distribution transformer, 400 kv system neutral and 415 V system neutral are solidly grounded and medium voltage 11 KV neutral system grounding through high resistance to facilitate ground fault relaying and transient over-voltage reduction. An integrated station ground grid for power station and switchyard will be provided for grounding of equipment and structures maintaining step and touch potentials within the safe limits. Earth mat will be provided throughout the plant. Section - 8 Page 51 of 103

154 Lightning protection for building/structures/equipment such as chimney, cooling tower, switchyard etc. will be provided Lighting Lighting system will be with 240 volt AC for normal lighting and 220 volt DC for emergency lighting. Normal AC lighting will be from 415 V AC 3 phase, 4 wire supply through lighting transformers. At least 20% of the normal lighting fixtures will be connected from the emergency lighting distribution board for automatic changeover. Illumination levels at various places will be according to international practice. Basically indoor illumination will be with fluorescent fittings. All lightings will be Energy efficient type and mercury vapour lamps will be used in areas like the turbine hall. Outdoor illumination will be achieved by Sodium vapour or mercury vapour in combination with flood lights Emergency Diesel Generator To enable the unit to shutdown safely during complete AC supply failure in the station (Blackout shutdown), certain important plant auxiliaries will be provided with a reliable AC power supply through a separate source. For this purpose, Three (3) Nos. 415 V quick starting diesel generator set with automatic mains failure (AMF) will be provided. Three Nos. of Diesel Generators of 1750KVA capacity each shall be provided. Emergency power derived from the Diesel Generator is used for essential services and safe shut down and battery charging in the event of total black out. For all emergency equipments, emergency lighting etc. automatic change over has been envisaged Workshop Electrical workshop will be provided for the day to day maintenance of electrical equipment of the plant. Suggested list of workshop equipment given below. i. Crane ii. Puller iii. Motor test bench iv. Tons tester Section - 8 Page 52 of 103

155 v. Meter and relay test vi. Bearing heater etc MRT / Electrical Lab A MRT / Electrical lab will be provided for the day to day maintenance of testing and calibration of the electrical equipment of the power plant. Section - 8 Page 53 of 103

156 8.3.0 Control & Instrumentation Systems Plant Control & Instrumentation provide a simple effective and fail-safe means for reliable and efficient operation of the plant under dynamic conditions and for attainment of maximum station availability. To achieve this objective, Control and Monitoring facilities are designed so that operation of the Boiler, Turbine, and Generator along with their major auxiliaries would be accomplished from a CCR (Central Control Room). From the CCR, operators would start-up, load, unload, release for remote dispatch, shutdown and monitor the steam generator, turbine and other auxiliaries of the plant. To fulfill the above functional requirements, a Distributed Digital Control, Monitoring and Information System (DDCMIS) with TFT / Keyboard operation for SG and TG controls and hard-wired back-up controls with monitoring and controlling devices needed for operation is envisaged. All field instruments like transmitters for Temperature, Flow, Pressure, Level and Differential pressure are of Smart type with HART Protocol. For systematic and sequential start-up / shutdown and safe operation of Boiler, Burner Management System (BMS) with fail-safe cards has been envisaged and shall be part of DDCMIS. All the control packages of Turbine-Generator, Boiler and their auxiliaries are preferably of the integral part of DDCMIS and from same family of hardware. In case micro-processor based TG and SG controls are from separate vendors, then the same is hooked-up to DDCMIS through necessary interfacing units. Provision for Third party Instruments / System shall be hooked up to DDCMIS. DDCMIS system configuration Scheme for Unit I (Typical for Unit II) & Common System Between two Units are enclosed in the Drawing No: CCE CI (Sheet 1 of 2) & (Sheet 2 of 2) Plant Control & Monitoring Philosophy The control and Monitoring philosophy envisaged Control from two Locations: From Unit Control Room (UCR) From Local Control Station for Off site & auxiliary plants Section - 8 Page 54 of 103

157 Control & Monitoring from UCR TFT operation a) All equipment associated with the steam generator viz., Burner Management System (BMS), Boiler start up system, Feed water system, Steam temperature Control system (STC), Auxiliary Pressure Reducing and Desuperheating Station (APRDS), HP bypass system, Primary / Secondary air system, fuel oil system, Flue gas system, Soot Blower System etc., are envisaged to be operable from TFT stations mounted on the Unit Control Desk (UCD) b) All equipment associated with Turbine Generator viz, Automatic Turbine Run up System (ATRS), Turbine Electro-hydraulic governing control system(ehg), Automatic Turbine Tester(ATT), LP bypass system, Gland steam control system(gsc), Main steam / Extraction steam system, Condensate system, Heater drains and vent system, LP dosing system, etc., are to be operated from TFT stations mounted on the UCD. c) All the balance of main plant equipment, auxiliaries, valves and dampers shall be operable from bank of TFT stations on the UCD. d) Selection facility such as Auto / Manual and standby for equipment are provided in the TFT stations Operation from Hardwired Unit Control Panel (UCP) a) Steam Generator, Turbine Generator and their Auxiliaries b) In addition to TFT / KBD operation, Emergency manual shutdown (Trip) facility is provided in manual trip of the Steam generator, Steam Turbine and major auxiliaries of the Unit Control Panel (UCP) Control & Monitoring from Local Stations Main plant Drives Local emergency stop push buttons shall be provided for all main plant pumps and fans. Local open / close / stop push buttons with remote / local facility shall be provided as an integral part of valve actuators for all motor operated isolating Section - 8 Page 55 of 103

158 and bypass valves and dampers, except solenoid valves and solenoid operated drives. Utility Plants Utilities such as Ash handling system, Instrument / Service air compressors, Coal handling system and Water Treatment Plant shall be operated automatically from PLC based local control systems with serial link to DDCMIS for monitoring. Common Auxiliaries such as CW, ACW, DMCWP, CT fans, Fuel oil system, CW make up system etc. shall be controlled from common DDCMIS provided with Local/remote I/O cabinets as applicable with facility for local / remote control Control Processor Distributed Digital Control, Monitoring and Information System (DDCMIS) shall comprise of Modulating Control, Sequence Control, Interlocking and Protection, Monitoring and Information System, Data Archiving, Performance Calculation, and Operator Interfacing Units. The micro-processor based distributed digital control system shall have Multi tasking Controllers envisaged in complete redundant mode and has the capability to perform the following tasks either separately or in a combined form: i. Open loop control (binary) ii. iii. Closed loop control (analog modulating) Plant monitoring/signal acquisition and processing The micro-processor based system has the capability to perform the above tasks either separately or in a combined form. DDCMIS capable to handle for ARC Tags. As multi-function controllers have a number of control functions and are preferred to be in completely redundant mode, security of control functions including those of protection would be maintained even with the loss of the active controller as well as the functions could be taken over by standby controller. Section - 8 Page 56 of 103

159 Non-redundant Signal Acquisition and Processing Modules for Monitoring Functions Primary instruments for monitoring functions are provided separate from those for control tasks. Keeping this segregation of field instruments, the system philosophy could adopt separate controllers for monitoring tasks. Monitoring task being less critical compared to control tasks; the controllers for monitoring could be Nonredundant. Alternatively, as the hardware for monitoring functions is generally similar/ identical to those for the control tasks, it is possible to combine the monitoring portions with control tasks. However, in view of the general practice of control engineering, separate non- redundant controllers shall be provided for this function Controller Task Allocations The system has overall control tasks having appropriate redundancy built in for all the system functions both at processor and peripheral level. No failure of any single peripheral or processor leads to any system function being lost. For the system with multi-function controllers, functional distribution is adopted and geographically, the system can be centralized. Each functional group consists of dedicated microprocessors including redundancy and dedicated input and output processing. The redundant multifunctional controllers are in a hot back up mode. The back-up controller takes over the function of the failed processor within one loop cycle time. Following segregation for regulating controls is proposed: Coordinated controls and Fuel feed control. Air flow and excess air correction. Furnace draft. Mill related controls such as air flow/feeder rate/outlet temperature controls. Separator/ water collection vessel level/overflow control Deaerator level/pressure, hot well level SH steam temperature control Section - 8 Page 57 of 103

160 RH steam Temperature control HP / LP heaters Secondary air damper control Segregation further depends upon I/O handling capacity of controller. Other loops of the plant e.g. miscellaneous loops can be distributed amongst the above controllers. Each group has sufficient spare capacity of at least 25% to meet modification / extension of the system. Multi-function controllers can incorporate the corresponding interlocks (open loop control tasks of the system). Interlock and modulating controls are to be so assigned to the controllers in such a way that failure of any controller does not lead to shut down of the entire unit. Typical loop cycle times for critical control loops like Furnace Draft, Feed Water Control and Air Flow would be < 100 msecs & rest of < 250 msecs. The loop timing from input status change to output contact actuation does not exceed 50 msecs for protective functions and 100 msecs for the interlock and sequential control tasks. While allocating control tasks for Interlock Protection, following criteria are also to be satisfied: 1) Left and right air-flue gas paths do not share controllers. 2) Left and right water paths do not share redundant controllers. 3) Those auxiliaries who are common to both paths will be resident in the controllers of the left / right paths so that both paths will not be lost due to the failure of a controller. 4) The Air and Water paths do not share controllers. The system has capability to provide held contact, maintained contact or a held contact till completion of the control action. Further system has the capability of either torque or position seating of the valves/dampers. Section - 8 Page 58 of 103

161 Automation In addition to the normal protection interlock and sequential control open loop tasks, the control system may be implemented to provide a high degree of automated operation of the plant. The automation system tasks include requisite sequencing for start-up, raising the load to target load, emergency safe shut down etc. under various conditions Automation System Philosophy The system envisaged is based on modern network orientation and is totally flexible in its adaptability to process structures, to the safety and availability requirements of main and auxiliary plants and the communication needs of the user. The control system has the following four functions:- a) Signal Conditioning (I/O System) b) Control functions c) Man-Machine interface d) System communication Signal Conditioning The signal conditioning is done in order to filter out the process noise and other electrical disturbances of the signal, protect the system against high voltage transients, and convert the analog / binary signal to digital form. The I/O sub system therefore, converts the process signal to a form that the controllers can use it to perform computational tasks. Microprocessor based Opto/Galvanic isolation is provided Control Functions All processing and computational tasks are completed in the controllers using standard software modules and procedures. A program library with built-in macros is used for constantly recurring functions. The controllers are built around high performance microprocessor and have a multi tasking operating system. This facilitates simultaneous processing of relevant programs with freely selective cycle times. Section - 8 Page 59 of 103

162 Man - Machine Interface Communication takes place between operator, process and the system. Communication consists of TFT observations, operations and plant controls, system configurations, diagnostics and data archiving, reports and logs, X-Y plots, bar charts etc. The TFT based monitor systems have the advantage of not only reporting the plant station and variable values but also the process mimics Communication System The communication network of a distributed control system is the heart of the system. All the functions of the system are tied with the real time network, failure of which leads to the catastrophic failure of the entire system. The communication needs to meet the following requirements: a) Complete redundancy for data highways as well as communication controllers. b) Deterministic protocols so that each controller can have guaranteed access to the information. c) High throughput to handle plant wide information base. d) Complete network Diagnostics / Status information up to card level shall be provided Central Control room Central Control room will be partitioned into different rooms to house the following equipment: a) Unit control panel (UCP), Unit Control desk (UCD) and printers (SOE / logging / alarm) in the main control room. b) The C&I system cabinet shall consists of electrical auxiliary cabinets, steam generator and turbine auxiliary system cabinets in the unit electronic cubicle room. c) Steam and water analyzing system (SWAS) room. d) Graphic (Color) printers e) Character alarm printers f) Line printer for logs Section - 8 Page 60 of 103

163 Unit Control Desk The unit, functional group/drive level control and operation of all main plant equipment and auxiliaries including non synchronizing breakers would be from a set of monitors mounted on a control desk. This unit control desk (UCD) would house the following items: Monitors for operation, control and monitoring of steam generator and its auxiliaries, turbine generator and its auxiliaries and balance of plant equipment. Alarm monitors Telephone handsets All these monitors are supported by the following peripherals which are located in the control room The operator can perform the following operations from monitors in the UCD through keyboards: Operation of all control valves, control dampers, motor operated valves, interlocked isolating valves and dampers, non-interlocked isolating valves and dampers, motor operated bypass valves of control valves, warm-up valves, drain valves and vent valves in the steam generator, turbine generator and its auxiliaries and auxiliary electrical systems. Operation of pumps and fans associated with the steam generator, turbine generator, feed cycle and other auxiliary systems. Call for overview, group display, individual loop display etc. and carryout associated control operations. In addition a separate monitor with keyboard and printer each for maintenance engineer, shift in charge engineer, performance calculation and management information system would be provided. However, plant operations from these monitors would be inhibited except for maintenance engineer s monitor Unit Control Panel A limited operation from back up unit control panel is envisaged for emergency shut down. The unit control panel will house a limited number of around 200 annunciation windows and instruments like console inserts, trip push buttons for Section - 8 Page 61 of 103

164 boiler, turbine and major HT drives, digital display units. The electrical section of the panel includes annunciation, mimics, hardware like synchronizing switches, selector switches and meters for operation and monitoring of generator circuit breaker and generator field breakers, electrical unit and common auxiliary power supply system Control Panel and Operator Interface Plant operation is primarily envisaged through TFT/KBD. Redundancy in functionalities of TFT/KBD is provided such that on failure of any TFT, any other TFT takes over these functions, thus with the loss of a TFT/KBD, no control/monitoring function is lost. As backup to Boiler, Turbine, Generator (BTG) hardwired backup PB stations; switches etc. are mounted on mosaic grid panel for emergency shutdown of the main equipment/unit Operating Stations a) Main Control Console The main control console provides the primary man-machine interface through the operator station. In DDCMIS for the Unit I, the station consists of Seven (6) sets of utility TFTs and keyboards in which two (2) operator station for Boiler & Auxiliaries, Three (3) for Turbine & Auxiliaries and one (1) for Electrical. Four (4) numbers of LVS (Size 65 / 70 ) monitoring this unit. The TFT units are of interactive type, providing the operator with the ability to issue commands via. Through keyboards. Overview of the plant systems, complete controls and monitoring of the plant equipment and parameters, including performance of start-up/shutdown, normal plant operation and emergency operations, are accessible from any one of the TFT units. In addition, one (1) no of vibrations monitoring system, one(1) no for Burner Management System and one(1) no for Turbine stress control system (TSC) shall be provided. The above setup is typical for Unit II. Each OWS will consist of Operator Terminals (OT) based on latest PC or Work Station with redundant communication link, 21 Color Graphic (TFT) Monitor, and QWERTY Keyboard and Optical mouse. 1 No. of Color Laser Printer for Graphics, 1 no. of B/W Laser Printer for log and 1 no. of B/W Dot Matrix printer for Alarm are connected in network along with main control consoles. Equipment status, start permissive check and step-by-step instructions are Section - 8 Page 62 of 103

165 displayed on the TFT screens for guiding the operator during various plant and equipment start-up and shutdown operations. On a plant fault, system trouble or equipment mal-function, necessary operating instructions are displayed automatically to direct the operator to alleviate the abnormal conditions. These operator guides are of intelligent, easy to follow and designed to enhance plant availability. b) Shift Supervisor Station: The shift supervisor station of Unit I & II each consists of 1 No. of TFT monitor, 1 no of Optical Mouse and one Keyboard. c) C & I Station (Computer Room / Engineer Room): The computer room/engineer room is located adjacent to the unit control room to provide easy access for control room personnel. This room contains all Distributed Digital Control, Monitoring and Information System (DDCMIS) related equipment necessary for configuring and maintaining the power block as follows: i) Main Control Console of Unit I and II each consists of 2 nos. of Engineering Station with DVD Read / Writer and one network color laser printer and 1 No. of Performance Calculations System with B/W Laser Printer, 1 No. of Sequence of Events System with 1 no. of B/W Laser Printer 1 No. of Historical Storage and Retrieval System with DVD Read / Writer and 1 no. of B/W Laser Printer, 1 No. of Smart Transmitter Monitoring Station with B/W Laser Pinter and 1 No. of Boiler tube leakage detector system with 1 No. of B/W laser printer for Unit I. This setup is typical for Unit-II. ii) Engineer workstation with 21 TFT monitor with QWERTY Keyboard and Optical Mouse for each console and all programming devices for configuration of the system and graphics. iii) Computer cabinet and Floppy Discs / Cartridge Magnetic Tape / Pen drives / Memory Cards for the storage, retrieval, handling and transfer of the system data. Section - 8 Page 63 of 103

166 d) Common Unit BOP The Common system shall consists of Two(2) nos of Operating Station with One (1) no of LVS(Size 65 /70 ). Overview of the Common Unit plant systems, complete controls and monitoring of the plant common unit equipment and parameters, including performance of start-up/shutdown, normal plant operation and emergency operations, are accessible from any one of the TFT units. Engineering station consists of One (1) of Engineering Station with Color Laser Printer and One (1) no of Historical Storage System for Common Unit shall be provided. In addition of One(1) no of Chief Engineer station with Black and White Laser printer, 1 no of Management Information System with B/W Laser Printer, 1 no of OPC client Redundant server station with Color Laser Printer and also Connection facility for ERP station with its Clients Large Video Screens Large Video Screen (LVS) Size of 65 / 70 display unit with suitable operator work station have been envisaged for all units and suitably interfaced with DCS for monitoring of salient plant parameters, plant status, alarms, graphics etc. These screens shall be placed in upright encasement in front of the Operator s Stations. Human ergonomics must be considered while deciding placement of these screens. The system shall have facility of complete and partial overview of the plant, display of alarms in the form of normal window appearance, display of important parameters of the plant, trend and bar graphs, status of electrical system etc. Large Video Screen system shall be based on Digital Light processing Technology. Windows NT based controller shall be provided so that any applications based on Windows NT can be displayed on the wall. The software shall have capability to display various windows on any part and any size on the screen. The system shall have facility to zoom any part of the display on the screen and move anywhere on the screen. Controller shall be integrated with the DCS through dual hot redundant link TFT/LCD Monitor The monitors are of 21 inches high resolution (1600 x 1248) color monitors with glare-free screens to provide the operator with sharp, clear and easy-to-read graphic and text displays. The response time is not more than 1 second. All keyboards / key pads are of totally enclosed type. Each key entry is confirmed by a Section - 8 Page 64 of 103

167 sound e.g. a beep. Monitors with 3D capabilities for graphics are preferred. The following displays are envisaged: Overview of plant Graphics (Plant Schematics) - Line display of data and plant status including electrical parameters Bar graphs Trends (Trend point and trend group) Alarms Open & close loop schemes including instrument face plate Various logs & reports Display of messages representing commands and process steps during process upset including help message Simulations & optimizations Diagnostic display Tuning Panel Keyboard Key-boards are of ASCII with QWERTY type with custom keys for dedicated graphics and group displays. These keys are re-assignable by Owner s program personnel. Keyboards are of totally enclosed keyboard type System Architecture Utility TFT monitors are connected either on Proprietary Data Highway at one end and Ethernet TCP/IP on other end or can be connected directly on Ethernet, TCP/IP bus as per manufacturers standard as per system configuration enclosed Data Highway Cabling Considerations Data highway cables have a larger bandwidth. Any disturbance of the highway could have catastrophic consequences for the plant. Special precautions shall be taken for laying of the cables such that they are free from noise and ground loops/circulating currents. Considering this, special care with respect to electrical isolation of the cable is taken. Section - 8 Page 65 of 103

168 8.3.6 Redundancy in I/O 100% redundancy shall be provided for all input/output cards, used for executing closed loop/sequential interlock functions. Redundant cards are not envisaged data acquisition / monitoring functions i. CPU ii. iii. iv. Bus (Data Highway) I/O Power supply 100% redundancy shall be provided for critical I/Os, used for executing closed loop / sequential interlock functions. Redundant cards are not envisaged data acquisition / monitoring functions Steam Generator and Auxiliaries Control The control system provides a simple effective fail safe means for reliable and efficient operation of the steam generator with its associated auxiliaries for attainment of maximum availability and maintaining plant parametric values at desired controlled levels. The main controls for the steam generator essentially comprise of the following: 1. Coordinated master control system 2. Combustion control 2.1. Fuel flow control 2.2. Air flow control 3. Furnace draft control 4. Feed Water & recirculation control (Boiler start up control) 5. Superheated steam temperature control 6. Reheat steam temperature control 7. Mill Temperature Control 8. CBD tank level control 9. Soot blower system pressure control 10. PRDS control 11. Secondary air damper control 12. Primary Air header pressure control 13. Seperator level control; Associated BFP scoop controls 14. Cold end average temperature control for air preheaters Section - 8 Page 66 of 103

169 8.3.8 Binary Controls Binary logic controls are envisaged for the sequence, protection and interlock operation of major plant auxiliaries. Some of the major auxiliaries / drives are: ID fans FD fans PA fans Mill Systems Seal air fans Reheater protection BMS/FSSS SH/RH spray block valves and isolation valves LFO, HFO pump Feed water circulating pump/sub cooling control Soot blower control Coal Feeder Control Regenerative Air Heaters Steam Turbine Generator and Auxiliary Control For the Steam Turbine Generator, some of the important controls and monitoring requirements are listed below: Generator slot and bearing temperature measurements Shaft sealing through sealing oil net work Hydrogen cooling system and hydrogen purity monitoring Hot and cold gas temperature monitoring and control Turbo supervisory system ETS / TSC system CW pumps BCW Pumps CEPs BFPs ATRS HP / LP Heaters EHG control System Automatic Turbine Testing (ATT) Turbine Protection System Section - 8 Page 67 of 103

170 Generator Auxiliaries System In addition to the above integral controls, the following controls for turbine related auxiliaries are also envisaged for steam turbine & steam turbine generator: Hot well level control and condensate pumps minimum recirculation Deaerator level control Deaerator pressure control Heaters level control Boiler feed pump minimum recirculation control Auxiliary steam to steam jet air ejector pressure control HP bypass control Gland steam Pressure control Balance-of-Plant Controls The following controls for balance of Plant are envisaged: HP / LP Heater Level Control Normal & emergency Drain PRDS control (Main steam and Cold Reheat Steam) LDO Pressure Control HFO Pressure Control Atomizing steam Pressure Control Fuel oil pumps - outlet pressure and temperature controls Fuel oil tanks - floor coil heating Fuel oil tanks - Suction heating Unit condensate floating tank level DM make up pumps - recirculation Circulating water pumps Auxiliary cooling water pumps Electrical system breakers control and monitoring Condenser online tube cleaning system(coltcs) Plant Auxiliaries /Off Side plants shall be operated from their respective local control panels or monitor stations located in the local area control rooms. Some of the auxiliaries will have operational facility from central control room as well as from local panels. The control system for each of the plant auxiliaries, off site plant andtheir man machine interface requirement and DDCMIS interface in the central control room shall be as follows: Section - 8 Page 68 of 103

171 Sl. Control Man Machine System No. System Interface 1 DM plant PLC based MMI stations and Local Panel 2 Compressed air system. Microprocessor Based MMI stations and Local Panel DDCMIS Interface Through Dual Redundant PLC gate way /Converter for Monitoring Through Dual Redundant Communication for monitoring 3 Air conditioning and ventilation system PLC based MMI stations and Local Panel Through Dual Redundant PLC gate way /Converter for Monitoring 4 Switch Yard System PLC based SCADA Through Dual Redundant PLC gate way /Converter for Monitoring 5 Circulating water pumps and auxiliaries 6 Auxiliary cooling water pumps DDCMIS based UCD/Local Panel DDCMIS based UCD/Local Panel 7 Makeup water system DDCMIS based UCD/Local Panel Directly Wired with main control room panels or through RTU as per site condition Directly Wired with main control room panels or through RTU as per site condition. Directly Wired with main control room panels. 8 Cooling tower fans DDCMIS based UCD//Local Panel Directly Wired with main control room panels. 9 Fuel oil forwarding pump DDCMIS based UCD/Local Panel Directly Wired with main control room panels or through RTU as per site condition. 10 CW makeup pumps DDCMIS based UGD/Local Panel Directly Wired with main control room panels. 11 Effluent Treatment system 12 Clarifier system(raw water pre treatment plant & chlorination system) 13 Clarifier water and service water system chlorination system Local relay Local Panel No interface with DDCMIS panel PLC based Local Panel Through Dual Redundant PLC gate way /Converter for Monitoring PLC based MMI stations and Local Panel Through Dual Redundant PLC gate way /Converter for Monitoring 14 Sump pumps Local relay panel 15 Potable water system Local relay panel Local Panel Local Panel Hardwired Indication No interface with DCS Section - 8 Page 69 of 103

172 Sl. Control Man Machine System No. System Interface DDCMIS Interface 16 Raw water pumping PLC based Local Panel Through Dual Redundant PLC gate way /Converter for Monitoring 17 H2 Plant PLC based MMI stations and Local Panel Through Dual Redundant PLC gate way /Converter for Monitoring 18 Coal Handling Plant PLC based Local Panel Through Dual Redundant PLC gate way /Converter for Monitoring 19 Ash Handling Plant PLC based Local Panel Through Dual Redundant PLC gate way /Converter for Monitoring 20 Pretreated & Desaltation PLC based Local Panel Through Dual Redundant PLC gate way /Converter for Monitoring 21 Condenser Online Tube Cleansing System (COLTCS ) PLC Based MMI stations and Local Panel Through Dual Redundant PLC gate way /Converter for Monitoring 22 SWAS PLC Based MMI stations and Local Panel Through Dual Redundant PLC gate way /Converter for Monitoring 23 Electrical Numerical Relay Microprocessor based Local Panel Hardwired Indication 24 Mill Reject PLC Based MMI stations and Local Panel Through Dual Redundant PLC gate way /Converter for Monitoring 25 Condenser Polishing System 26 Continuous Emission Monitoring System (CEMS) PLC Based MMI stations and Local Panel PLC Based MMI stations and Local Panel Through Dual Redundant PLC gate way /Converter for Monitoring Through Dual Redundant PLC gate way /Converter for Monitoring 27 Auxiliary Boiler PLC Based MMI stations and Local Panel Through Dual Redundant PLC gate way /Converter for Monitoring 28 Fuel Oil Unloading & Storage System Local panel relay Local Panel No interface with DCS Section - 8 Page 70 of 103

173 Sl. Control System No. System 29 Fire Detection & Alarm Microprocessor System based analogue addressable type 30 Fire Fighting System Microprocessor Based control system Man Machine Interface Master Fire Alarm Panel (MFAP) PLC Based DDCMIS Interface Critical group alarms hardwired to DCS for Monitoring. Redundant communication link with MFAP for monitoring 31 Ambient Air Quality Management System (AAQMS) Data acquisition system with PC DAS Based Serial link communication from DAS PLC Description PLC systems shall utilize microprocessor-based controllers. Each controller shall consist of redundant pairs of CPUs (Central Processing Units), each capable of performing the control functions assigned to that functional controller. Each functional controller shall consist of redundant fully capable processors, operating in a "hot standby" mode, with transfer of function to the backup processor in the event of failure of the operating processor. PLC system consists of 1 no of Operating Station, 1 no of Engineering Station with 1 no of color laser printer and configuration Scheme enclosed in the Drawing No: CCE CI Communications between PLC system and DDCMIS shall be accomplished via an interconnecting communication bus. The communications network shall be provided with redundant communications paths PLC General Requirement The PLC hardware shall include all electronics required to perform signal conditioning functions required to process the various types of input / output signals such as 4-20 ma, RTD & T/C inputs, etc. It shall also be capable of implementing closed and open loop controls. The PLC system features shall include but not be limited to the following: i. Scan time for digital and pulse inputs not greater than 250msec. ii. Scan time for all analog inputs not greater than 500msec. iii. Execution time not greater than 120msec. Section - 8 Page 71 of 103

174 iv. Max. System loading of 60% under worst loading conditions. v. Independent measurement circuit for each measurement. Grouping of signals in each card is subject to approval at the time of detailed engineering. vi. Failure of one logic shall not result in failure of the other logics. vii. Overall accuracy of measurement signals shall be 0.5%. viii. Extensive self diagnostic alarms and power supply failure alarm. The PLC system processor shall Minimum 32 / 64 bit processor with floating point capability and Battery back-up of not less than 1 week Master Clock System A stand alone master clock system with suitable time format is envisaged for synchronizing with the clock system of DDCMIS of SG, TG and Common Unit PLC system & micro-processor based systems. Necessary hardware and software requirements for all units are met Plant Security and Surveillance System (PSS) A complete integrated plant security and surveillance system (PSS) complete with all hardware and software as required shall be provided. The system shall to be provided include all necessary hardware, software, firmware, interfaces and accessories, all related civil and masonry work required for implementing a fully functional PSS system for a modern power generation utility. Configuration Scheme enclosed in the Drawing No: CCE CI Plant security and surveillance system (PSS) shall be an integrated system comprising the following systems/facilities: I. CCTV Monitoring of Plant area/ equipment II. Security card access system CCTV Monitoring System Closed Circuit Television System (CCTV) with all equipment and accessories shall be installed for the purpose of surveillance of major Electrical Drive areas e.g. Boiler Feed Pumps, ID Fans, FD and PA fans, Mills, Condensate Extraction Pumps and critical areas like Turbine hall, firing floor, CW/ACW Pump House, Ash Handling Plant areas, fuel oil pump house, ESP, cable gallery, SWGR room, Section - 8 Page 72 of 103

175 transformer bay, along boundary walls (with suitable intervals), etc. so that, by and large, all important areas & equipment can be brought under surveillance. Also, cameras shall be installed at the Main Gate and other common auxiliary plants. All the cameras shall be connected to a central redundant microprocessor based video switcher/control system to be located in unit control room area. CCTV monitors are envisaged in the Plant security room as well as in central Control room. Provision for CCTV shall be in 32 TFT - 1 no in Server area and 29 TFT 2 nos in Security room shall be provided for monitoring for the over all plant. Purpose of CCTV monitoring system shall be to meet the following: i. To provide the plant operators with an overview of the important plant equipment so that they can ascertain that there are no obvious mechanical problems. ii. To provide another angle on any intruder that may have broken into the premises. Securities personnel may then if required manually track the intruder. CCTV monitoring system shall meet the following requirements: i. Simultaneous remote centralized surveillance from both CCR & also from security room. ii. iii. Display of images in a multiplexed fashion. Recording of images in a time lapsed fashion and playback facility of images. Security Card Access System Purpose of the facility is to control access to all vital areas within the important plant buildings by electronic card reader system. One (1) no 21 TFT shall be provided for Security card Access System Features of the I & C system Suitable number of gateways is provided for accepting the DAS inputs from various sub systems. Smart transmitters (HART Protocol) with turn down ratio 100 or above have been considered. Transmitters are provided for temperature control loop. Section - 8 Page 73 of 103

176 Two out of three logic is implemented for critical loops; and for partial critical loops one out of two logic is applied. For non-critical loops, no redundancy has been envisaged. All protection logic, Critical control Loops I/O s should be taken as hardwired and independent of communication network (DDCMIS network). For laboratory testing: Laboratory instruments for testing and commissioning are included on selection basis. For threaded type fittings, swage lock type fixing with double ferrules is used. Field cables are terminated in marshalling panels. 20% wired spare slots are provided in C & I cabinets for future extensions / modifications. For signal distribution or fan outs, suitable electronic cards (Opto couplers) as part of DDCMIS system are envisaged. Field mounted transmitters and analyzers are envisaged to be installed in "Field Instrument Enclosures (FIE)". The DDCMIS has hardware and software capability (open system) to provide Management Information System. The DDCMIS has capability to store historical data storage and retrieved on cartridge tape drive / Pen Drives. For interfacing DDCMIS with field instruments, switchgear etc. and for providing contact multiplication, auxiliary relays of suitable rating for output are used. Displacer type Level transmitters shall be employed for HP / LP heaters and Hotwell level measurements. Flame proof enclosure with intrinsic safety for the instruments coming under hazardous area (Hydrogen & Fuel Oil System) HFO / LDO flow meters for boiler are based on Coriolis technology. All supervisory instruments like recorders, scanners, Totalizer etc are microprocessor based except indicators with built-in alarm facility in scanners only. Recorders are of paperless / chartless type and indicators are of bar graph type. Section - 8 Page 74 of 103

177 Major I & C systems Proposed Apart from above, following major I & C system are also envisaged Annunciation System A Microprocessor based annunciation system (AS) would be provided with ISA sequence ring back feature. The system has the features of first-up and nonfirst-up sequences along with reflashing facility for the grouped faults located on the unit control desk. A set of annunciation push buttons would be provided at different sections on unit control panel. Provision will be made to acknowledge alarm from TFT/ key boards. The number of windows and defaults would be decided during detail engineering stage. The annunciation system will be preferably integral to DCS. Alternatively a redundant processor based stand alone annunciation would be envisaged Sequence of Events Recording System A microprocessor based sequence of events recording systems (SER) with adequate redundancy features and an input capacity of 512 points for each unit (including electrical and switch yard signals) would be provided to log trips, cause of trips and other important faults to diagnose the cause of plant trip with a resolution of less than one (1) millisecond or one (1) millisecond. The system will be provided with a dedicated printer located in the main control room. The sequence of events recording will be preferably integral to DCS. Alternatively a redundant processor based stand alone SER would be envisaged Vibration Monitoring system Field mounted vibration sensor / transmitter would be used for all HT (6.6 KV) drives and HT motors on X-axis & Y-axis. The 4-20 ma signals from the field are directly acquired in the DCS. A Turbovisory system along with sensors would be provided for steam turbine to cover vibration, axial shift, differential temperature etc. Necessary analog signal for alarm and trip functions shall be provided Historical Data storage and retrieval (HDSR) System The HDSR shall provide medium & long term storage of select data points for subsequent retrieval display and analysis. The data shall be saved online on hard disk and automatically transferred to portable storage device once in every 24 Section - 8 Page 75 of 103

178 hours periodically for long term storage. The minimum Storage capacity of data shall be 5 years. The HDSR system shall provide storage of status/ value of analog & Digital inputs for each unit. The data to be stored in the above system shall include alarm and event list, periodic plant data including data required for Residual life assessment, selected logs/reports such as event activated logs, trip analysis log, start-up log etc. The data/information to be stored & frequency of storage and retrieval shall be as finalized during detailed engineering. The system shall provide user-friendly operator functions to retrieve the data from historical storage. It shall be possible to retrieve the selected data on OWS/LVS or printer in form of trend/report by specifying date, time & period. The logs/reports for at least last Fifteen (15) days shall be available on the disk. In addition to above, the system shall also have facility to store & retrieve important plant data for a very long duration (plant life) on portable storage device like DVD / Pen drive, Blue Ray Disc etc. These data will include any data from the database as well as processed/computed data based on various calculations / transformation. The retrieved data from portable storage device should be possible to be presented in form of X-T display, X-Y display, logs, reports, etc Condenser online Tube Cleaning (COLTCS) System The continuous cleaning of condensers and heat exchangers maintains the efficiency of heat transfer without mechanical or chemical cleaning of the tubes and without increasing the number of outages. Condenser tube cleaning is necessary as raw water induces different types of fouling which affects the inside of condenser tubes. Settling of suspended materials like silt, mud, slime, biological fouling due to the presence of bacteria/marine organisms in water, crystallization of soluble elements and formation of seashell colonies leads to fouling of Condenser Tubes. Cleaning of internal tube surface is done by continuous circulation of sponge rubber balls with sizes slightly larger than the tube diameter. These sponge rubber balls are injected into the cooling water inlet header. The water flow carries these balls into the inlet water boxes, then through the tubes and finally into the ball strainer located at the cooling water outlet header. Section - 8 Page 76 of 103

179 The efficiency of heat transfer in the condensers of steam turbines has a direct effect on the power generation. The main factors of COLTCS are given below: a. Ball Monitor A condenser tube cleaning system is efficient only when it circulates a sufficient number of cleaning balls having an adequate diameter. The ball monitor continuously checks the condition of circulating balls, sorts the balls into usable and worn out groups and counts the number of balls in circulation. b. Automatic Ball Feeder An automatic ball feeder, controlled by a PLC, receives information from each ball monitor. The feeder tops up the required balls in each of the system automatically c. Cleaning Balls Ball quality assures improved cleaning efficiency and integrity of protective tube film. Balls having different hardness and sizes are provided depending on the specific application. d. Debris Filters Debris filters for protecting the heat transfer equipment against small to medium size wastes that may have passed through upstream screens. Debris filters are installed directly on the pipeline between pumps and downstream equipment Condensate Polishing Plant Sodium and Chloride limit in case of both CWT & AVT feed water shall be maintained up to 2 ppb each at Condensate Polishing Plant outlet. It is proposed to install 100% capacity Condensate Polishing Unit for each of the units. The proposed design features of the Condensate polishing plant being provided by Supplier and it is controlled by dedicated PLC Control Valves All control valves would have 15% excess capacity over and above the design flow value. The control valve design shall be suitable for the required fail safe Section - 8 Page 77 of 103

180 conditions of process / equipment. Specially designed anti-cavitations, multistage pressure drop trim shall be used for high pressure drop application. All final control elements (control valves and control dampers) would have actuators of pneumatic type / hydraulic type. All actuators would be sized so that the final control elements operate properly even when the upstream pressure exceeds 110% of the maximum value. Pneumatic actuators would be provided with air failure lock and remote release, limit switches, adjustable minimum and maximum stops, local position indicators, positioners, electronic with SMART position transmitters and solenoid valves in accordance with the system requirements Analytical System This section covers the philosophy and design criteria for continuous on line analytical measurements of important plant media such as water, steam and flue gas. All analytical instruments will be of microprocessor based only. Adequate number of analytical instruments would be provided for continuous monitoring of demineralized water, condensate, feed water and steam. The analytical instruments proposed are for specific conductivity, cationic conductivity, ph, dissolved oxygen and silica measurements. All testing / analyzing stations should have auto regeneration facility. Provision for Uploading online data to TNPCB shall be provided. And also all testing /analyzing stations shall be auto report generation. Analytical measurements are of two types: a) Continuous Emission Monitoring System (CEMS): Flue gas analysis is carried out for percentage oxygen (O 2 ), SOx/NOx measurement (IN-situ type) and smoke emission density. Oxygen analyzer is of zirconium oxide probe based. Particulate analyses are envisaged at ID outlet and at stack to monitor the quality of emission after ESP. This is controlled by dedicated PLC. b) Steam and Water Analysis: Continuous analysis is done on steam and water media to establish their purity and suitability for long life of pressure parts. The measurements are carried out at different cycle points of the plant to establish Conductivity, ph & Dissolved oxygen content. The steam and water analysis system (SWAS) includes all requisite analyzers, sampling Section - 8 Page 78 of 103

181 system; complete with sampling table chiller unit and analyzer panels. All data will be available in DAS. There shall be two panels, wet panel for sample conditioning and dry panel for housing analyzers. Dry panel shall be kept in A/C room. Steam and Water Analysis system and Gas sampling System Recorder Type of Range of Monitor Distributed S. No Sample Stream Alarm Measurement / Indicator Control Input System 01 Make up DM Water a) GRAB Yes b) Conductivity 0-10 Micro (Mho / cm) Yes Yes Yes 02 Hotwell A&B outlet condensate a)grab Yes b) Conductivity 0-10 Micro (Mho / cm) Yes Yes Yes c)ph 6-14 ph Yes Yes Yes 03 Condensate Pump Discharge a)grab Yes b)ph 6-14 ph Yes Yes Yes c)dissolved Oxygen 0-20 ppb ppb ppb Yes Yes Yes d)conductivity 0-10 Micro mhos / cm Yes Yes Yes e)cation conduction 0-10 Micro mhos / cm Yes f)silica ppb Yes Yes Yes 04 Feed water BF Booster pumps suction (Deaerator) a)grab Yes b)dissolved Oxygen 0-20 ppb ppb Yes Yes Yes c)ph 6-14 ph Yes d)conductivity 0-10 Micro mhos/cm Yes Section - 8 Page 79 of 103

182 S. No Sample Stream 05 Feed water Economiser Inlet Recorder Type of Range of Monitor Distributed Alarm Measurement / Indicator Control Input System a)grab Yes b)ph 6-14 ph Yes Yes Yes c)conductivity 0-10 Micro mhos / cm Yes Yes Yes 06 Separator/water collection vessel water discharge line d)hydrazine 0-50 ppb ppb Yes Yes Yes a)grab Yes b)ph 6-14 ph Yes Yes Yes c)conductivity Micro mhos / cm Yes Yes Yes d)silica 0-50,0-100,0-500, ppb Yes Yes Yes a)grab Yes 07 Boiler Saturated Steam b)conductivity Micro mhos / cm Yes Yes Yes c)silica 0-50, ppb Yes Yes Yes 08 FP Discharge a)grab Yes b)conductivity 0-10 Micro mhos / cm Yes c)silica ppb Yes Yes Yes d)ph 6-14 ph Yes Yes Yes e)hydrazine 0-50, ppb Yes 09 Hot Reheat Steam a)grab Yes b)conductivity 0-10 Micro mhos/ cm Yes Yes Yes c)ph 6-14 ph Yes Yes Yes 10 Stator water flow conductivity measurement a)grab Yes b)conductivity 0-10 Micro mhos/ cm Yes Yes Yes c)ph 6-14pH Yes Yes Yes Section - 8 Page 80 of 103

183 Recorder Type of Range of Monitor Distributed S. No Sample Stream Alarm Measurement / Indicator Control Input System 11 Main Steam a)grab Yes b)conductivity 0-10 / 0-1 Micro mhos / cm Yes Yes Yes c)after cation 0-1 / 0-2 Micro mhos / cm Yes Yes Yes d)silica ppb Yes Yes Yes Gas Sampling System 12 Flue gas at IDFAN Inlet 13 Flue gas after air heater 14 Flue gas at discharge of ID Fans (to Chimney) 15 Flue gas at Eco. Inlet 16 Flue gas at Emission of 8 times of Chimney base diameter e)ph 6-14 ph Particulate Emission a)oxygen Percentage b)combustibles (Carbon Monoxide) Mg/ Nm % Vol. Oxygen ppm ppm Yes Yes Yes Yes Yes Yes Yes a) NOx ppm Yes Yes Yes b) SO ,0-1000, , ppm Yes Yes Yes c)smoke density 0-100% Yes Yes Yes Oxygen % 0-10% Vol. 0 Yes Yes Yes Particulate Chimney Height Mg/Nm 3 Yes Yes Yes Furnace Temperature Probes Two numbers of furnace temperature probes will be provided before platen superheater and/or before reheater regions and will be electrically operated, fully retractable type. The probes will be furnished with complete actuating mechanism Furnace & Flame Viewing System (Flame Cameras) The flame cameras shall be suitable for direct online continuous viewing in the central control room of the coal and oil flame and condition of the furnace internals including slogging of the water walls and any other deterioration in the Section - 8 Page 81 of 103

184 furnace condition. The nos. of such flame cameras shall be four (4) numbers minimum. The flame camera system will consist of the following facilities / components as a minimum: a) 19" High resolution color monitor. b) Facility for zooming and adjustment of iris from the monitor. c) Proper cooling arrangement (preferably air) and protection against cooling medium failure. d) Weatherproof local control box for mounting of electronics. e) All necessary remote/ local programming tool. f) All interconnecting cable and termination device. g) Any other accessory to make the system completely operational Ambient Air Quality Monitoring System AAQMS shall be provided to check upon the ambient air quality inside and around the power plant and capable of generating required periodic reports for submission to relevant Central & State regulatory agencies by Owner. Ambient air quality shall be monitored for concentration levels of selected gaseous pollutants at different locations within the power station boundary and adjoining areas as per the ambient air quality monitoring guidelines of Central & State regulatory agencies like, MOEF, Central & State Pollution Control Boards (PCBs) prevailing during contract execution phase. AAQMS system including the analyzers being supplied shall meet all applicable requirements/guidelines of relevant Central & State regulatory agencies like, MOEF, Central & State Pollution Control Boards (PCBs) etc. or of US EPA in the absence of the same. It is the sole responsibility of the Vendor to obtain the necessary approval. Owner has no liability towards the same. AAQMS system shall include the following: a) AAQMS Stations- 4 numbers b) Centralized AAQMS Data Acquisition System The following measurements will be provided for each station; - SO2 - NOX Section - 8 Page 82 of 103

185 - CO - CO2 - Suspended Particulate Matter (PM10) - Suspended Particulate Matter (PM 2.5)- Respiratory - Ozone (O3) - At One location only. Monitoring and report generation shall be carried out either in a centralized PC based Data Acquisition for AAQMS station at CCR and linked with plant DCS with OPC link. AAQMS for each plant location shall be a fixed type, self contained Station. One (1) no Station shall be located at the UP wind direction path. Balance three (3) number Stations shall be located at different plant locations considering the factors like downwind direction, sensitive receptor, population etc. The exact location of the monitoring station(s) shall be decided in consultation with Owner and regulatory agencies during project implementation phase. Each AAQMS Station shall include the following including analyzers, accessories, calibration facility, mounting racks/ cabinets and housing shelter, Data Acquisition System etc. but not limited to the same: a) Individual Gas analyzers for the parameters specified b) Necessary sampling systems for the AAQMS analyzers c) Multi gas calibration system d) Zero air generators e) Hydrogen Generator, f) Calibration gas cylinders g) Mounting cabinet/ rack for analyzers and accessories h) Housing shelter for AAQMS equipment provided shall be environmentally Conditioned, walk-in type shelter complete with lighting and convenience receptacles. i) UPS & lighting power supply complete with distribution facility j) PC Based Data Acquisition System for AAQMS Station Fire Detection /Alarm and Fire Proof Sealing System A fire alarm system would be provided to facilitate visual and audible fire detection at the incipient stage of fire in the power station. This system will comprise manual call points located at strategic locations in areas which are Section - 8 Page 83 of 103

186 normally manned and automatic fire detectors such a smoke detectors/rate of rise of temperature detectors located in plant areas, such as control room, switch gear room, cable vaults, battery rooms etc., to detect fire at an early stage. Linear heat detectors will be provided for the cable gallery and conveyors. Switchgear rooms cable entry points in to Breakers to be sealed with proof sealing. Infrared type umber detector will be provided for the conveyor gallery. Fire proof sealing will be provided for all cable penetrations through walls and floors to prevent spreading of fire from one are/floor to another Instrumentation Pipes/Tubes and Fittings For all pipe mounted instruments, pipes and fittings of appropriate material would be used. For all high pressure and temperature services (above 40Kg/cm²), two isolating valves of NB25 size would be used. For level and flow instruments NB25 size isolating valves would be used. For other services and measurements NB15 size valves would be used. For remote located instruments like transmitters, tubes and fittings of appropriate material and rating would be used. Open type transmitter racks would be provided to group and mount all pressure, flow and level transmitters. Temperature transmitters would be mounted in enclosed boxes. Junction boxes would be provided for termination of all field switches like pressure, temperature, flow and level Air supply for Pneumatic Equipment Oil free, dry instrument air from instrument air heater at a pressure of 6-8 bars (g) would be drawn for various instrument auxiliaries like control valve positioners, control damper positioners, I/P converters etc. Each of this pneumatic equipment which requires air supply at different levels would be provided with an air-filter regulator AC and DC Power Supply for Control and Monitoring System Uninterruptible power supply (UPS) For panel mounted instruments, TFTs, printers, analyzers, recorder etc., 230V single phase AC un-interruptible power supply for each unit will be made available. This power supply will be derived from un-interruptible power supply system having two (2) sets of (2X100%) converters and (2 X 100%) inverters with one hour back up battery. Also a standby AC supply will be provided as a Section - 8 Page 84 of 103

187 back up to the inverters which will be switched on through static switch in case of inverter failure. DC Power Supply for Control and Monitoring System 24 V DC supply for instrumentation and control systems such as closed loop controls, sequence controls, automatic turbine run-up system, protection and interlock system, sequence-of-events recording system and annunciation etc. This 24VDC system shall be provided individually with 2 X 100% Converters and 2 X 100% inverters Cables Individual / pair shielded and overall shielded twisted pair copper cables would be used for analog signals and overall shielded cables would be used for digital signals. All these cables are armored. All the insulation including overall sheath would be FRLS quality. The size of the wire would be 0.5 mm FRLS 2.5 sq. mm. Copper control cable would be used for cabling between MCC, control system and solenoid valves. Compensating cables will be provided for connecting the thermocouple inputs to the DCS for measurement system and to the temperature transmitter for control application. The interconnecting cables between any two cabinets and between cabinets and panels would be of prefabricated type. The communication bus of the distributed system would be coaxial / twisted pair cable. Any other special cables if required, for any system would be included in the respective vendor s scope of supply Erection Hardware and cables All Erection Hardware like impulse pipe, elbows, bends manifold will be supplied as per process requirements. All control cables will be paired (for analogue signals) core (for Binary signals). The core size will be 0.5 mm 2 & extension cables (for TC) will have core size 1.0 mm 2 and triad cables will be used for RTD. All these cables will be rated for 650 V; armoured and external sheath will be ST- 2 FRLS Control and Instrumentation Laboratory An Air Conditioned C&I lab will be provided for carrying out the day to day maintenance of testing requirement of instrumentation scheme of the power plant. Section - 8 Page 85 of 103

188 i. The work benches will have computer aided calibration system work benches shall include both measurement and generation facilities for process signals. Calibration stations shall have the modules which exactly fulfill complete requirement of the total plant. ii. In addition to above work benches, other desk mounted calibration test instruments are envisaged. iii. Also portable calibrating / test instruments in sufficient quantities are envisaged which will help O&M staff to use in the field. iv. All testing /analyzing stations shall be auto report generation Local Instruments Minimum number of local instruments would be provided to enable local operators to supervise and monitor equipment / process operation. Bourdon type Pressure gauges shall have an accuracy of ± 1% of FSD, weather proof with dial size of minimum 150mm and connection shall be ½ NPT. Pressure Switch shall have an accuracy of ± 1% of FSD, weather proof, Snap Action micro Switch, 2 SPDT contact switches with Rating of 5 Amp, 240V AC or 0.2 Amp, 220V DC. The instrument connection shall be ½ NPT and Electrical connection of ¾ NPT. Level switch Connections will be flanged in accordance with the piping / vessel trim specification. Instrument protection will be of IP65. These shall be weather proof, Snap Action Switch, 2 SPDT contact Switches with Rating of 5 Amp, 240V AC or 0.2 Amp, 220V DC and the Electrical connection of ¾ NPT. Reflex and Tubular type level gauges will be provided for water storage tank as per the requirement. Transparent type level gauge will be provided in separator/water collection vessel. Material shall be Tempered borosilicate resistant to thermal shock with Integral cocks/ drain. Scale shall be graduated in mmwc and 1.5 Meters maximum length. On-line type Rotameter of size 50 NB and below lines and Bypass type Rotameter for above 50 NB lines with the accuracy of ± 2 % and the material of Borosilicate Section - 8 Page 86 of 103

189 glass Metering Tube, 316 SS Float, Teflon Packing, 304 SS End fittings. Scale shall be direct reading, length of 250 mm and end connection of Screwed NPT. Flow Nozzle shall be used for steam and feed water and other services orifice plate. The material shall be of SS316 minimum and the connection BW ends to ASA B 16.9 for flow nozzle and ANSI flanged/weld neck for Orifices. The Beta ratio should be 0.4 to 0.7. All Transmitters shall be microprocessor based with the output of 4-20 ma and loop powered. Accuracy of the transmitter will be ±0.1%. Protection will be of IP65. These shall support international field bus and driving capacity up to 500 ohms. For Two wire transmitters, 24V DC powered from the control system and for four [4] wire transmitters (if any) 110V AC power supply will be provided Earthing Separate electronic earthing system with dedicated earthing pits would be envisaged as part of respective vendor s scope Spares Tests Adequate essential spares are proposed for the complete I & C equipment. Tests for I & C equipment will be envisages as per standards which includes Control Valve (CV) test, flow nozzle calibration test, Factory Acceptance Tests (FAT) and Site Acceptance Tests (SAT) Plant Communication System The plant will be provided with effective and reliable communication with intercommunication system and internal telephone system. The intercommunication system will have both private and paging modes with handsets located at various strategic points. The plant Communication System will consist of the following: i. Public Address System. ii. Telephone systems complete with EPABX, telephone sets in the Power Section - 8 Page 87 of 103

190 Plant and associated administration buildings. iii. Walky-talkies for the plant communication with base station Public Address System Public address system will be used to issue instructions, calling and conversing with key operating and maintenance personnel. The system shall comprise of two (2) nos. separate and independent groups of communication system namely: 1 No. for Unit I 1 No. for Unit II 1 No. for common facilities (BOP area) Master station for the common facilities shall be located in central control room within BTG area. Between groups communication shall be made between Master to Master only. Power supply to communication system shall be fed from UPS. Public address system shall also be hooked up to telephone system Telephone System The Power plant will be provided with microprocessor based intercom telephone system to facilitate inter-communication for operation/administrative purposes. This consists of an Electronic Private Automatic Branch Exchange (EPABX) of suitable capacity. All the instruments for subscribers will also have the provision for hooking up with P&T lines. The EPABX will be capable of accepting & sending up to a maximum of twenty (20) external lines & two hundreds (200) internal lines with expandable and up to 15 days of recording between the power station, control room and western room central dispatch control centre is provided. Following features will be available in EPABX system: i. Call interruption / priority ii. Emergency alert iii. Automatic call back iv. Automatic call diversion v. Conference call The telephone sets will be installed in various areas of power plant. The EPABX at Power plant and EPABX at colony will be interconnected. Section - 8 Page 88 of 103

191 In hazard areas such as oil storage, wall telephone sets with explosion proof and corrosion resistant metal cases will be provided Training All Equipment / Instrument contractor will be responsible for providing training to employer s personnel on offered systems at contractor s works/contractor s associate s works. It shall include training operators in the use of system, in the programming and hardware maintenance of the equipment to the extent that the Employer s personnel can make corrections and changes to the systems programs and maintains the system s hardware. The maintenance and operator training shall include lectures and hands on experience on a similar type of equipment/system at manufacturers works and site and/or training simulator. The details of hardware and software training shall be as finalized during detailed engineering and shall be subject to employer s approval Enterprises Resource Planning (ERP) System A proven and fully computerized SAP (Web server) based ERP system has been envisaged for Maintenance & Inventory Management of various equipment of the plant. The system will integrate with the plant DCS through suitable interface for the Utilization of the Global database of DCS, having connectivity with Utilities & Offsite systems in addition to the main plant system. The system shall be proven type suitable for industrial plant application and shall be organized in a networked LAN as well as Web Enabled structure adhering to international accounting practices. For monitoring and control the project, schedule has to be provided by the bidder in the SAP format. The following Modules are required as part of ERP System: a) Project Management b) Maintenance Management c) Purchas, Stores and Inventory d) Finance and Control e) Payroll and HRD f) Power Trading / Management with real time power flow, Load Management Section - 8 Page 89 of 103

192 g) Interface for Non ERP systems such as Thermal Performance Monitoring, DDCMIS, etc. The ERP system shall be implemented and used for the plant construction activity also in addition to the above function. The required module for the same is to be considered during detailed engineering stage. It has implemented SAP based ERP to monitor the ongoing thermal power projects and extend the same for the station once the unit is commissioned Hardware Requirement The ERP system shall be licensed for 100 users. The hardware required like routers/switches, servers, PCS with printers shall be supplied for 100 users exclusively for ERP system Training of ERP Systems Training on ERP systems of various modules shall be given to minimum ten Engineers for implementation and maintenance. Additional ten engineers for system operation shall be trained. Section - 8 Page 90 of 103

193 8.4.0 Civil & Structural Works Plant Grading The elevation of the plot is around (+) 10.0 m above MSL. The grade level of the built up area of the plant has been considered at approximately same elevation. The final grade level of the plant will, however be decided after detailed contour survey of the area at a later date Seismic Consideration The power station area is located in Seismic Zone - III as per the demarcation of IS: of Indian code of practice. Analysis and design of structures to resist the seismic forces would be carried out as per the provisions stipulated in the code. The applicable important factors would be duly considered in the design Wind Condition The maximum wind pressure including winds of short duration as specified in Indian Standard Code of Practice IS: 875 (latest revision) would be adopted for the zone. The provision of Indian Standard Code of Practice IS: 875 with appropriate coefficient for variation of heights and shape will be considered for design Civil Works Plant civil works shall comprise of plant layout, micro-grading, geo-technical investigation, in-plant roads and drains (Storm, plant drains) in plant area, Boiler & auxiliaries foundations, ESP foundations, ID duct foundations, FAN (ID, FD, PA etc) foundations, Concrete paving (Transformer yard to Chimney), twin flue RCC chimney of 275 m height, including forced vegetation, lift, electrical works, wind tunnel study, transformer yard civil works including rails, fencing and oil water separator and oil pits, providing railway line within the plant area, CW ducts-cw pump house to cooling tower, Cooling towers, cooling tower switchgear rooms, pipe and cable trestles, cable trenches/duct banks, civil works for all below & above ground piping including CW pipe, Sewerage system (septic tanks and soak pits), Fire station, Drill tower, Boundary wall, Gate house, Guard Towers etc Complete Civil, Structural & architectural Works includes the following: Power house, Miscellaneous bays, control tower Mill & Bunker bay Section - 8 Page 91 of 103

194 Service building Coal handling plant, loco shed ESP control rooms Ash handling plant RCC Chimney Watch Towers Fuel oil storage area, pump house, unloading Water treatment plant, clarified water pump house DG building, DG foundation Roads, drains and Peripheral road Compound wall Compressor house Air washer rooms Fire water pump house Pipe/Cable racks Cooling water pump house with forebay NDCT Raw water reservoir, pump house DM plant, Chlorination plant, Hydrogen plant, effluent treatment plant, Central Monitoring Basin Any other civil structural architectural works (including temporary works) required from system point of view only will be provided. Non Plant buildings such as Canteen, Medical Centre, security House, Fire station building, Car scooter Parking, Administrative building etc The tentative building sizes considered for the proposed power plant are as follows: S. No Description Size 1. T.G Building 282 x T.G Foundation - 3. ESP control 40 x 15 x Bunker 130 x 12.5 x Plant compressor house 90 x 40 x 8 Section - 8 Page 92 of 103

195 S. No Description Size 6. Air washer 20 x 15 x 6 7. Service building 70 x 40 x 8 8. DG house 40x 20 x 8 9. Cooling water pump house 65 x 12 x Work shop 75 x 50 x Canteen 80 x 40 x Fire station 15 x 10 x Fuel oil unloading pump house 25 x 15 x Administrative building 150 x 100 x Clarifier Φ Hydrogen generation plant 75 x 75 x Ash air compressor 45 x 20 x Fly ash Φ x Bottom ash Φ x Clarified water storage tank 150 x 150 x D.M plant 40 x 15 x ETP Area 60 x Road m Chimney 275 m 25. Pile details Φ m depth Piling and Foundation Main Power House All the main plant columns are to be supported on pile foundations, according to the soil data. The grade of concrete shall be M-25 (as provided in Stage-I). Section - 8 Page 93 of 103

196 Turbo Generator Foundation The Turbo-Generator shall be supported on a RCC deck at the operating floor level. The RCC deck in turn, shall be supported on vibration isolation system consisting of helical springs and viscous dampers. The vibration isolation system shall rest on RCC columns which shall in turn rest on RCC base raft. The LP condenser below the LP turbine shall also rest on the same RCC base raft. The top deck directly supporting the Turbo-Generator shall be grade M30. RCC columns and beams shall be of grade M30. The RCC base raft of the TG foundation shall rest on piles Other Equipment Foundation The Boiler Feed Pumps (TDBFP & MDBFP), ID, FD & PA fans and Coal Mills shall also be supported on RCC top deck which in turn shall be supported by springs cum viscous dampers (Vibrating Isolation System). Spring supported foundations shall also be provided for coal crushers (both primary & secondary). The springcum viscous dampers shall in turn rest on RCC raft/strip foundation supported on piles. The grade of concrete for top deck of boiler feed pumps, fans and mills shall be M25 and that for the raft/strip footing shall also M25. All main plant foundations shall be on piles. The dia of the piles and type of pile to be used for the foundations to be decided after conducting detailed soil investigations. Based on the available geotechnical data, minimum pile lengths vary from 25 m to 30 m. The actual load carrying capacity of piles shall be ensured during detailed design and also from field load tests by conducting initial load test on test piles Geo-technical Investigation For the proposed power plant at ash dyke area, a separate geotechnical investigation is to be done during the engineering / construction stage. However, TANGEDCO already conducted the soil investigation at the nearby area which is considered for this report. It is envisaged that shallow foundation may be provided for minor structures and for major equipments and structures, pile foundations may be provided. Cast in situ piles shall be of RCC with grade of Section - 8 Page 94 of 103

197 concrete as M25. In case the actual ground conditions are found to be different during detailed investigation stage, type of foundation and the quantity may have to be reassessed. The chemical analysis of the sub-soil and water are not done at this stage Plant roads The main plant road and all the roads inside the plant area two lane/single lane expect the peripheral road shall be laid as RCC roads. The main plant road shall be 10 m wide. All Double lane roads shall be of 7.5 m wide concrete with 2.5 m wide shoulders on both sides of the road. Single lane roads shall be of 4 m wide RCC and 1.5 m wide shoulders on both sides of the road. Access roads to building/facilities shall generally be two/ single lane or to suit the approach to the building. Peripheral road shall be laid as black topping road of 4 m wide. On either side of roads a width of 1m shall be provided for drains Main Plant Civil Works Structural System Main plant complex shall consist of the following buildings and facilities. a) Main Power house b) Control Tower Block c) Mill/Bunker Building d) Coal conveyor galleries and transfer points in Boiler area e) Trestle supports for cables and pipelines f) Auxiliary buildings including Compressor house, DG set building, ESP control room building, air washer room, etc. The layout and general arrangements details of the main plant shall be given Main Power House This shall be a framed structure consisting of structural steel columns and beams. This building shall be independent. Structures supporting platforms and floors around T.G and electrical bay shall be structural steel columns and beams. EOT cranes shall be provided in T.G Bay. One number elevator for passenger shall be provided for Main Power House. Section - 8 Page 95 of 103

198 Civil foundation shall take into consideration soil bearing capacity, water table and loading. Minimum grade of concrete for various works shall be generally used as per IS: 456. M15 Concrete Mix / Grade Fill concrete Type of structure M15 M20 M20 Blinding layer below foundations, trenches and under ground structures, foundation below brick wall, etc. Minimum thickness of layer shall be 75 mm Plinth protection work around buildings Base plate encasement, encasement of structural steel work, all RCC paving work, ground floor slabs, cable and pipe trenches, etc. All RCC structures and equipment foundations, super structure, grade beams, columns, roof slabs, TG foundations, transformer foundations and all underground RCC structures, M25/M30 / M40 cable and pipe rack foundation, pedestals, etc. water retaining structures below and above ground, TG top deck, boiler foundations, mill foundations, precast concrete work, crusher foundations, etc. M 30 M25 M25 M 40 M30 M25 M mm thick below water / liquid retaining structures. Roads Foundation Base Diagonal Columns / NDCT Shell Precast Foundation / Chimney & Silo. Shell M30 Inter mixing of different grade of concrete in the same structure shall not be allowed normally. However in the case of structures like RCC chimney, natural draft cooling towers, etc. different mix will be permitted at different levels. Section - 8 Page 96 of 103

199 HSRC cement can be used for the civil concrete works at below ground level. Reinforcement bars shall be as per the following codes: Due to saline nature of ground fusion bonded epoxy treated TMT bars may be used below ground level. High Yield Strength Deformed bars as per IS: 1786 is used above ground level. High Yield Strength Deformed bars IS: 1786 Mild steel bars Grade I of IS: 432 Welded wire fabric IS: Control Tower The control tower shall be a separate block projecting out from BC bay towards boiler from the electrical bay. This shall be made of structural steel frame. One number elevator for passenger shall be provided for service building Mill / Bunker Building There shall be one mill / bunker building located on one side of boiler. This building shall accommodate mills. This shall have intermediate floors for feeder and tripper. Mill and bunker building shall be braced steel structure in longitudinal as well as transverse direction. Bunkers shall be made of structural steel having complete stainless steel lining. Bunker size shall be designed for a capacity corresponding to 12 hrs consumption of coal, besides 4 hours dead storage Conveyor galleries and Transfer Points Overhead conveyor galleries shall be of structural steel frame with powder coated 0.6 mm galvanium sheets roofing and cladding provided between ESP and boiler area. Chequered plate walk ways shall be provided. Transfer points and intermediate supporting trestles shall be made of braced steel framed structures. Brick cladding can be provided at the bottom with height of 3.5m/4m Cable and Pipe Racks Structural steel trestles shall be provided for supporting overhead cables and pipe lines of fuel/water supply in the main plant and outlaying areas. However, for below ground routing, RCC trench with removable pre cast cover slabs shall be used. Section - 8 Page 97 of 103

200 Auxiliary Buildings All the auxiliary building in the main plant area mentioned above shall generally be made of RCC framed structure with in filled brick walls. Open (shallow) foundation system has been envisaged for these buildings Floors and Walls Roof AB bay of main power-house shall be provided with cold formed troughed steel sections used as covering cum permanent shuttering over which either foam concrete or RCC slab would be placed. All other roofs and floors shall be made of RCC slab. External cladding of main plant building other than transfer points shall be of brick masonry having minimum one brick thickness. All the partition walls shall also be of brick masonry. Due to saline atmospheric condition Powder coated 0.6mm galvanism sheets shall be used for roofing and cladding of transfer points. However internal partition in control tower shall consist of glazed aluminium Architectural and Finishing Works External and other finishes shall be decided based on good aesthetic and architectural considerations. The operating floor of main power house shall be finished with heavy duty concrete tiles (Carborundum tiles). Unit control rooms, control equipment rooms and ESP control room shall have flexible PVC tile flooring. Computer room shall have particle board false flooring. Acid resistant tiles shall be used in battery room floor. Terrazzo flooring shall be provided for entrance area, staircase, entrance lobby, office areas and toilets. All other floor areas shall generally be finished with metallic hardener topping. Combination of resin bonded granular textured finish (Vineratex) and sandtex matt paint shall be used for external finish. Inside wall of unit control room shall be provided with white marble tiles. All main doors shall be made of aluminium (glazed). All control rooms shall have doors windows and partitions made of glazed aluminium. Ceiling shall be white washed and internal wall faces shall receive distemper/acrylic emulsion paint. Steel structures shall be finished with chemical resistant paint on account of marine environment. Unit control room shall be provided with permanently colour coated lineal aluminium false ceiling. All air conditioned areas shall be provided with pre-laminated particle board false Section - 8 Page 98 of 103

201 ceiling. Boiler area shall be provided with RCC paving with metallic hardener topping Chimney A multi flue reinforced Concrete Chimney is preferred from environmental consideration, inspection and maintenance advantages and construction ease. The flue gas emission point shall be 275 Mts above the plant ground level. One number of Electrical operated Elevator is envisaged in the inner surface of the windshield for construction and maintenance as same to operate the elevator safely also during the rainy season and cyclone period. The chimney windshield would be of RCC with slip form method of construction. The chimney shaft will be of RCC with slip form construction on a RCC raft foundation. As per statutory requirements, aircraft warning light and lighting electrodes etc., on the top of the chimney would be provided. Liner (flue) shall be constructed from structural steel and shall be hung from the liner support platform near the Chimney top. The liner shall be provided with resin bonded wool type thermal insulation. The portion of the liner protecting above the Chimney roof shall be of stainless steel. Intermediate internal platform shall be provided for enabling access to various elevators of the stack and to provide lateral restraint to the steel liner. The structural steel transition inlet ducting shall be bottom supported. This transition ducting shall be suitably profiled from a rectangular shape at the chimney inlet to a circular shape inside the chimney where it shall be connected to the suspended circular steel liner through suitable (non-metallic) fluro elastometric fabric expansion compensators. Transition ducting shall also be thermally insulated. Fabric expansion compensators shall be installed after the transition ducts have been erected. Internal platform shall be structural steel construction and shall be supported from the wind shield. The floors/walkways shall be of chequered plate construction. The chimney roof shall, however comprise of a reinforced concrete slab supported over a grid of structural steel beams. The roof slab shall be protected by a layer of acid resistant tiles. The grade level slab shall be of reinforced concrete with a metallic hardener floor finish. Section - 8 Page 99 of 103

202 An internal structural steel staircase, supported from the shell wall, shall be provided for full height of the stack. This shall provide access to all internal platforms giving ample access to various elevations of the chimney. The stair treads shall be fabricated from chequered plates. The top external portion of the wind shield shall be coated with acid and heat resisting paint in alternate bands of colors red and white to meet the aviation safety requirements. The mini-shells and the top few meters of the internal surface of the wind shield shall be painted for acid and heat protection with bituminous paint. The other components of the chimney include a large roll-up door and a personnel access door at grade level, doors at all platform levels, a personnel access hatch in the roof slab, liner hatches, liner test ports, rain water drainage system, flue liner drainage system, louvers with bird screens for ventilation openings, electrical power supply, distribution boards, socket outlets, power and control cabling, raceway system, stair and platform lighting, lightning protection and grounding system, aviation obstruction lighting and communication system. Provisions shall be made for a proven rack and pinion elevator or any other type of elevator. All mild steel components shall be protected by a durable painting system. Mild steel discrete strakes shall be provided, at the top (usually 1/3 rd height) if found necessary from design requirements. The super structure shall be supported on a foundation system with piles Coal Handling System Coal shall be transported through sea to Ennore port and stored in the proposed coal berth 3 by TANGEDCO. Thereafter it shall be conveyed to coal handling plant area by use of closed belt conveyors by providing necessary transfer points, conveyor galleries, etc. Conveyor galleries, trestles, superstructure of crusher house and transfer houses will be of fabricated steel structure. Intermediate floors and roofs in transfer houses and crusher house will be of plastered brick/hollow block work / AC sheets and necessary windows louvers will be provided for natural lighting and ventilation. RC crusher foundation will have vibration isolation system from the crusher house building. Conveyor galleries Section - 8 Page 100 of 103

203 will be of concrete box section with provision of appropriate water proofing arrangement. The coal stock pile area shall be paved with RCC and also compacted grade having slope and drainage system. The coal bunkers housed between turbine building and boiler will be of structural steel frame with mild steel skin plate having stainless steel lining in the bottom portion of the hoppers Transfer Points Transfer point will be provided at every change of direction of the conveyors and at all elevation change points. This will have structural steel frame work with R.C.C. roof and floors. Cladding shall be of metal sheeting. Cladding for bottom of ground floor 3m height shall be with brick work Conveyor Galleries Overhead pipe conveyors are proposed. If belt conveyors, overhead conveyor galleries will be of structural steel frame with powder coated 0.6mm galvanium sheets roofing and cladding. Walkways are to be provided at sides and in between conveyors. The galleries will be supported on steel trestles which will have RCC/Pile foundation Recovery Water Pump House A recovery water pump house is envisaged Ash Handling System (Civil Works) The civil works involved in the ash handling system are the following: Ash slurry pump house Additional arrangements for decanting of ash water Shafts Ash slurry pipe Fuel Oil Handling System (Civil Works) The following civil works are to be provided for the Fuel Oil handling System. Pump house to have heaters, pressurizing pumps etc. A raised ramp for unloading the fuel oil from road tankers Foundations for storage tanks RCC dyke wall around the tank area. Miscellaneous foundations for pumps, pipe racks, pipelines etc. Section - 8 Page 101 of 103

204 DM plant, Filter house & R.O Plant Demineralization plant building shall be framed RCC Structure with in filled brick work. The concrete shall be of M-20 grade for all super structural work. The adequate size of the building shall be provided. Underground RCC neutralization pit shall be constructed in two compartments with concrete of grade M-25. Required size of neutralization pit shall be provided. The inside face of pit shall be provided with acid/alkali resistant lining. Condensate polishing unit, degasser and acid storage tanks being outdoor type installations. Only raft foundation along with dyke wall is envisaged. This shall be of RCC with concrete of grade M25. Adequate size of the building shall be provided. The foundation for 1 No. of D.M tank shall be of RCC of grade M-25. The diameter of ring beam for supporting the tank shall be about 13.4 m. A filter house cum filter water pump house building shall be constructed to house 2 gravity filters. The building shall be of RCC framed structure of grade m-25. Reverse Osmosis building shall be RCC framed structure of concrete of grade M20. The adequate size of the building shall be provided. The foundation for 2 Nos of Reverse Osmosis water tanks shall be constructed of RCC of grade M-25. The dia. of the ring beam shall be about 13 m Cooling Water System Water from existing cooling water forebay of NCTPS stage - II is proposed to be used for the CW system, protection of concrete and steel shall be provided. This shall include use of dense and durable concrete (M-25) with plasticizer cum water proofing agent, use of sulphate resistant cement, coating of reinforcement etc. All steel pipes used in CW system will be gunnited with a minimum thickness of 50 mm. CW ducts would be lined with concrete on both inside and outside surface. Minimum thickness of outside concrete layer shall be 75 mm. Alternately GRP pipes and ducts can be used in CW system. Section - 8 Page 102 of 103

205 Raw Water System A RCC raw water reservoir shall be provided with adequate capacity for storing sweet water requirements. One number raw water pump house shall be provided. Pump house shall be provided to the potable water reservoir for potable water supply. Sub-structure of the pump houses shall be of RCC while super structure shall be of steel with in filled brick panel walls and RCC cast-insitu roofing over permanent metal decking. In addition to the above one RCC fire water reservoir of 1000 cu.m capacity shall be provided in plant area for fire water storage. One no. fire water pump house shall be provided adjacent to the reservoir which will house fire water pumps. Sub-structure and super structure of the pump house shall be similar to that of the above referred pump house Switchyard Switchyard structures including equipment supports will be of galvanized steel. The foundations will be RCC spread footing. Cable trench, pits etc. will be of RCC with pre-cast RCC covers. Peripheral and internal roads will be provided for access during equipment maintenance. The entire area will be enclosed with suitable safety fencing and control gate Ancillary Buildings Ancillary building such as service building, electrical switchgear room building etc. shall be provided. These buildings shall generally be constructed of RCC frame work with infilled brickwork. Service building shall be separated from Main TG building, at least by 10 to 20 feet with partition wall to avoid noise Rain Water harvesting Scheme Suitable rain water harvesting scheme shall be provided for plant area building. Section - 8 Page 103 of 103

206 Section 9 Plant General Layout Arrangement Layout of the power plant has been optimized considering the space requirements of various equipments, buildings and structures, for 2 x 800 MW proposed Thermal Power Plant. The plot plan for the proposed Plant indicating the location of various components of the plant namely: - Boiler House - TG Building - Transformer and Switch yard - Fuel storage yard - Ash handling plant - Cooling Towers & CW pump house - Water treatment plant - Effluent Treatment Plant - Sewage Treatment Plant - Administrative Building / Security Building - Plants Roads and approach road from Main Road - Green Belt Area - Vacant space for FGD - Other miscellaneous buildings - Predominant wind directions as given by the wind rose to minimize pollution, fire risk etc - Availability of adequate space for fabrication/construction of equipments The plot of land has some undulations and would salient features of the site namely, general topography, wind direction, level and direction of road, rail and drainage, power evacuation corridor, raw water corridor from intake pump house etc. A proven layout with the transmission switchyard in front of power house block and the boiler, the electrostatic precipitators (ESP), the chimney and the coal handling plant at the rear has been envisaged. Space for flue gas desulphurization has also been provided as per the guidelines of statutory authorities. Section - 9 Page 1 of 4

207 The plant water system, pump houses, water tanks, DM plant etc. are logically located in close proximity of main plant. Provision of Administrative building security office, first aid centre, fire and safety office, workshop, stores, garage etc. would be kept, keeping in view their functional requirements. The ash handling and disposal facilities will include bottom ash storage bins, intermediate surge hoppers, fly ash bins, compressor house and other equipment of ash handling system with appropriate approach for disposal of dry fly ash through trucks. The plot for ash disposal is proposed adjacent the plant. The natural draft cooling towers of the station would be located in dust-free zone and away from switchyard to safeguard against possible deterioration of steel materials / electrical hardware by moist drift from the cooling tower. From the main access to the plant, the layout would provide a good view from the Administrative building. In the administrative building and Lube oil stores automatic smoke detectors to be envisaged for avoiding fire accidents. Adequate green belts encompassing the plot and vacant spaces have shown in the plot plan. The area of the green verge shall be more than four times the built up area. All facilities of the plant are laid out in close proximity to each other to the extent practicable so as to minimize the amount of land required. Necessary plant drainage system would be provided at the proposed power plant site. The layout also facilitates communication of personnel and material movement between the various facilities both during construction and also during subsequent operation and maintenance. The power station is configured such that the emissions from the stacks and cooling towers shall travel in the direction of prevailing wind away from the plant. The plot plan has been developed for an initial installation of 2 x 800 MW Thermal power plant. The entire TG hall shall be covered building with an overhead traveling crane. TG hall layout envisages longitudinal configuration of all generation sets. Section - 9 Page 2 of 4

208 Floor levels in AB bay 0.00 M, 8.5 M, 17.0 M Floor levels in B-C bay 0.00 M, 8.5 M, 17.0 M, 24.0 M, 32.0 M, 38.0 M. Level of operating floor Level of mezzanine floor Floor levels in control equipment room area HT / LT Switchgear and MCC location Minimum clear working space around equipment Clear Head room for pipes, cables and ducts from nearest floor Location of Deaerator Location of Heaters Location of BFP Location of Boiler MCC Clear approach width in front and rear of ESP Head Room for pipe/cables trestles at rail, road crossing Mill/Bunker building Location of Mills Elevation of ID Ducts routed perpendicular to boiler axis 17.0 M 8.5 M 5.1 M, 8.5 M, 13.5 M, 17.0 M, 24.0 M, 32.0 M HT Switchgear at 3.5 M and LT switch gear & MCC at 12.0 M in AB bay 1200 mm 2.50 M In B-C bay at EL M HP Heaters/LP Heaters at Operating Floor/ Mezzanine Floor respectively in BC Bay. A-B bay TDBFP at Operating Floor and MDBFP at Mezzanine Floor At 27.5 M in B-C bay 10m (Height=8M) 8 m a) Width =12.5 M (minimum) b)length = 10.5 M per mill walkway of 1500mm (min) between the mill/its foundation/ mill reject vessel edge and inner face of mill bay column On the sides of boiler M (Min.) (Bottom of Steel) Section - 9 Page 3 of 4

209 The 400 kv GIS switch yard comprises generator Transformers bays, station transformer bay,line bays & reactor bays. The generator transformers and auxiliary service transformer will be located between the turbine hall and the 400 KVA switch yard. The cooling tower and CW pump house are located such that CW pipe work will be minimum length. Plant roads have been configured such that each area is accessible and connected to Plant Buildings. The plant layout arrangements drawings are enclosed as follows: Description Over All Plot Plan SG & TG sectional view TG Building Floor plan Drawing No. CCE ME CCE ME CCE ME Section - 9 Page 4 of 4

210 Section - 10 Environmental Issues and Management Plan Environmental Considerations Coal fired thermal power station contribute to environmental pollution as follows: a) Atmospheric pollution through particulate and gaseous emissions. b) Thermal pollution of the surroundings. c) Pollution due to discharge of liquid and solid wastes. d) Noise pollution. Each one of the above sources of pollutions are discussed in more detail below: Atmospheric Pollution Contribution to atmospheric pollution can be from: a) Particulate emission from the stack as a result of the combustion of coal. b) Coal dust and ash particles due to their storage/disposal and handling. c) Sulphur dioxide. d) Nitrogen oxides. Particulate emission from the stack is governed by the Central Pollution Control Board Emission Regulations of July 1995 which states that for Thermal Power units of 200 MW capacity and greater; the particulate emission shall not exceed 100 mg/nm 3. This will be achieved by the use of Six (6) electrostatic precipitators with adequate fields in the direction of gas flow and two (2) bus sections perpendicular to the gas flow having an efficiency of 99.99% or better to limit the particulate emission to below 50 mg/nm 3 and then as per CPCB norms for reducing the SO 2 emission the ESP duct is connected with 275 M RCC Twin Flue Chimney through ID fan. Suitable dust suppression / extraction system shall be provided at crusher house junction tower, coal unloading area for the coal stock-yard so as to minimize dust nuisance due to coal handling system. The dust suppression system could be provided with ventilation system having back filters to drop the dust in the bunkers. Section - 10 Page 1 of 24

211 The blowing of dry ash from the ash disposal area also represents a pollution hazard. 100% ash collection and utilization is envisaged for this station and during emergency disposed to ash dyke in slurry form. Ash dyke will always be full of ash water to eliminate this hazard Sulphur Di-Oxide (SO 2 ) in Flue Gas For the control of sulphur dioxide the Emission Standards stipulate a minimum stack height of 220 Mtr for thermal power plants of unit size of above 200 MW to 499 MW and if the plant capacity is above 500 MW then stack height would be 275 Mtr. Considering the capacity of power plant, the 275 mtr high chimney with twin flue gas path is envisaged for 2 x 800 MW Coal Burners (To control Nitrogen Oxides emissions (NO 2 ) in Flue Gas) Presently there are no limitations for NO X emissions from the coal fired power plants. However the steam generator will use coal burners of proven, advanced design to reduce NO X production, and the boiler furnace will be provided with over fire air ports to further reduce NO X production Dust Suppression System (to control dust) For the control of fugitive dust emission within and around the coal handling plant, coal dust suppression systems would be provided. Dust suppression system would be installed at all the transfer points in coal handling plant and at coal stockyard Furnace (eliminates CO Emissions) Carbon Monoxide (CO) another kind of pollutant hardly exists in the modern power stations as design of combustion control equipment and the furnace eliminates, almost completely the possibility of incomplete combustion. The ground level concentration is expected to be within the limit prescribed by Ministry of Environment and Forest Pollution due to discharge of liquid and solid wastes This results primarily from the following areas: a) Effluent from the water treatment plant b) Run-off from coal handling area Section - 10 Page 2 of 24

212 c) Oil water mixture from fuel oil system d) Sewage from various buildings in the plant e) Ash pond effluent. f) Cooling Tower Blow down. Effluents from the demineralizer (DM) plant resin regeneration circuit, generally acidic from the cation units and alkaline from the anion units will be neutralized in a neutralizing pit. The neutralized effluent will have less than 50 ppm suspended solids and a ph value of about 7.5 to 8.0. The neutralized effluents will be led into the station sump. The run-off from the coal handling area will flow through ditches around the coal storage area and coal handling buildings into a common basin (settling tank) from where it will be pumped into the station sump. The oil-water mixture collected in the existing drains provided around the existing oil unloading area and the pump house etc. is led to an oil-water separator. The separated water containing less than 15 ppm oil will be led into the storm water drainage system which will finally discharge into station sump. The oil separated out will be led back to the oil storage tanks. Sewage treatment Aeration tank is required to dispose the sewage from the various buildings in the power plant as well as the colony. The effluents from the sewage treatment plant will be disposed of suitably. The Power cycle blow down will be controlled to maintain system solids loading within normal limits for proper water treatment and will have the heat extracted to maximize plant efficiency. The effluent will have less than 50 ppm suspended solids and a ph value of about 7.5 to 8.0. Generally cooling tower blow down will be returned to sea and in case of emergency cooling tower blow down water will be used for disposal of ash in slurry form to the existing ash dyke. Ash will settle down and ash water will prevent blowing of ash from ash pond. Some water will be evaporated from ash pond. Some of the excess ash water from ash pond will be treated / decanted through successive decantation tanks and pumped back to plant site for supplementing water available from plant drains for use in CHP dust suppression, BA hopper refractory cooling and watering of green belt. Section - 10 Page 3 of 24

213 In the later years, when ash utilisation is progressively increased, less cooling tower blowdown will be used for disposal of ash in slurry form. The cooling tower blow down and recycling of ash water from ash pond will be progressively reduced and more cooling tower blow down will be used for CHP dust suppression, BA hopper refractory cooling and watering of green belt. Excess cooling tower blow down, meeting CPCB standards, will be discharged into water system Fly Ash Management Coal consumption in the power sector during was about 120 million tonnes, as is expected to go upto about 220 million tonnes by the year and 372 million tonnes upto the year This will generate about 40% of coal consumed as ash. The question of disposal/utilization of fly ash, therefore, becomes very significant and assumes immediate importance from a National angle. Ministry of E&F has stipulated utilization of fly ash progressively for manufacture of construction materials. Fly ash essentially consists of spherical particles of crystalline matter and unburnt carbon. Its colour depends upon the quantity of carbon, varying from light to dark grey. The specific gravity lies between and the bulk density of loose dry fly ash is around 600 kg/cum. As per the current practice, large quantities of water are used for the transportation of fly ash in slurry form which otherwise could have been saved for other more important requirements. Thus, recovery of ash transport water becomes necessary in many cases. There is a considerable impact of fly ash on the environment. Fly ash particles are carried by wind, reduce visibility in the surroundings and causes respiratory diseases. The particles settle in far off places. Finer particles, still airborne, tend to create acid rain during the rainy season. Fly ash can cause corrosion in steel structures. The land in the vicinity of ash pond or even in far off places where wind carried particles settle, can turn alkaline due to alkali content in Fly Ash. In the building and construction industry, the shortfall in terms of building materials like bricks, cement and coarse aggregate have been projected as million numbers, 3.5 million tonnes and 20 million cubic meters respectively. Section - 10 Page 4 of 24

214 Presently building material is produced by exploiting nature resulting in unfavorable repercussions. Conventionally clay is used for manufacturing bricks. The top soil is available for a depth of about 3.0 M from the surface. The top soil erosion directly hampers cultivation and results in denuding of forests and vegetation, affecting the ecological balance. Similarly, aggregates formed by breaking rocks, may not be available everywhere. The above clearly brings out the need for a total fly Ash Management programme for its proper utilisation in view of the fact that fly ash will be generated by Thermal Power Plants in ever increasing quantity in the coming years. The disposal of enormous quantities of ash generated regularly from Thermal Power Stations has become a matter of National concern and attracted the technologies in the country. Western countries have been able to utilize nearly 77 percent of fly ash as against a mere 2.6 percent in India. With a view of proper utilization, fly ash has to be handled separately and fly ash has to be stored in dry form for subsequent utilisation. The dry fly ash could be transported in closed trucks for commercial utilisation. Alternately, to minimize the cost of transportation, fly ash utilisation plants could be located close to the Thermal Power Stations. Bottom ash after being collected in ash bins for decantation is conveyed in trucks outside the plant site and is used extensively as a replacement for cinders. The use of bottom ash in area filling has provided satisfactory over the years, by virtue of which it finds ready marketability. Fly ash, being a high temperature product, has pozzolonic properties and forms cement like material when mixed with lime and water. These properties make it suitable for a number of commercial uses; the most promising of these are as follows: Bulk utilisation Fly ash can be utilised in bulk form filling low lying areas, abandoned mines and in forming dykes and bunds. For this purpose, fly ash slurry is prepared specially to render the mass semi-rock once it settles in low lands, thereby making the reclamation of land possible. The slurry thus prepared is termed as `Emulgate'. Section - 10 Page 5 of 24

215 Emulgate can also be used to serve irrigation projects by creating bunds to channelize water. Other probable uses can be for making rail & canal embankments, filling for making roads, landscaping etc Value added utilisation: Modest quantities of fly ash can be used by generating a product which has some commercial value. The products are made by making use of some of the qualities of fly ash. The pozzolanic activity and lime reactivity of fly ash is employed for numerous uses including manufacture of building construction materials, as listed below: a) Fly ash clay bricks b) Fly ash - lime & sand bricks c) Cellular bricks /blocks d) Light weight aggregate e) Portland pozzolana cement f) Precast concrete blocks g) Septic tanks and sewerage pipes High Value utilisation Products/services of high value can be made by utilizing fly ash. The value of the end product is much more pronounced than the quantity of ash utilized. Probable usage/products are as follows: a) Treatment of acidic soil for waste land reclamation for agricultural purposes b) Construction of road sub-base and rigid pavements for runways. c) Manufacture of coagulants to remove turbidity of water. d) Extraction of valuable materials like Vanadium, Cadmium, Uranium etc from certain rich fly ashes. e) Manufacture of insulating bricks. For the proposed 2 X 800 MW power plant, fly ash will be collected in dry form. This dry fly ash will then be transported to the neighboring ash utilisation plants, to be set up by private parties, by truck. Any surplus fly ash not used in the manufacture will be disposed off in slurry form to the existing ash dyke based in Section - 10 Page 6 of 24

216 abandoned coalmines. In later years, when nearby mine area is fully exploited, some ash will be utilised as land fill in the spent mine area. Tamil Nadu Generation and Distribution Co. Ltd. will encourage the entrepreneurs to set up utilization of fly ash based cement plants near to Power Station by extending the following facilities: Issuing of fly ash by free of cost at plant boundary for a minimum period of ten (10) years. Allotment of land on nominal lease charge and Concession on power consumption charges, where ever considered necessary and feasible, appropriate technical, managerial assistance and marketing information would be provided. It is expected that it would be possible for the power station to draw fly ash management plan for utilisation of fly ash to an extent of 50% in the first year and increasing the utilisation rate at 60% fly ash per year such that 100% utilisation of fly ash could be made possible by the fourth year onwards Regulations for limiting Air Pollution Indian standards As per notification by Ministry of Environment and Forests, the emission limits for a) Suspended particulate matter : < 100 mg/nm 3 (SPM) emission (dust particulate from fly ash) b) Sulphur di-oxide : < 50 mg/nm 3 c) Nitrogen oxides : Not specified d) Coal dust particles during : Not specified Storage / handling of coal e) Dust in the ash disposal area : Not specified Generation Capacity Stack Height (Metres) 500 MW and above MW/210 MW and above to less than 500 MW 220 Less than 200 MW/210 MW H= 14 Q 0.3 where Q is emission rate of SO 2 in kg/hr, and H is Stack height in metres. Section - 10 Page 7 of 24

217 Based on the above standard and capacity of power plant, the 275 metre high chimney with twin flue gas path is envisaged for 2 x 800 MW. As per notification by Central Pollution Control Board for the ambient air Quality, the permitted limits of ground level concentrations in ambient air of pollutants considering Industrial, Residential, Sensitive areas National Ambient Air Quality Standards Pollutants Sulphurdioxide (SO 2 ) Timeweighted average Annual Average* Concentration in ambient air Method of Industrial Areas Residential, Rural & other Areas Sensitive Areas measurement 80 µg/m 3 60 µg/m 3 15 µg/m 3 - Improved West and Geake Method - Ultraviolet Fluorescence 24 hours** 120 µg/m 3 80 µg/m 3 30 µg/m 3 Oxides of Nitrogen as (NO 2 ) Annual Average* 80 µg/m 3 60 µg/m 3 15 µg/m 3 - Jacob & Hochheiser Modified (Na- Arsenite) Method 24 hours** 120 µg/m 3 80 µg/m 3 30 µg/m 3 - Gas Phase Chemiluminescence Suspended Annual 360 µg/m µg/m 3 70 µg/m 3 - High Volume Particulate Matter Average* Sampling, (SPM) (Average flow rate not less than 1.1 m 3 /minute) 24 hours** 500 µg/m µg/m µg/m 3 Respirable Annual 120 µg/m 3 60 µg/m 3 50 µg/m 3 -Respirable Particulate Matter Average* particulate matter (RPM) (size less than sampler 10 microns) 24 hours** 150 µg/m µg/m 3 75 µg/m 3 Section - 10 Page 8 of 24

218 Pollutants Timeweighted average Concentration in ambient air Method of Industrial Areas Residential, Rural & other Sensitive Areas measurement Areas Lead (Pb) Annual 1.0 µg/m µg/m µg/m 3 - ASS Method after Average* sampling using EPM 2000 or equivalent Filter paper 24 hours** 1.5 µg/m µg/m µg/m 3. Ammonia1 Annual 0.1 mg/ m mg/ m mg/m 3. Average* 24 hours** 0.4 mg/ m mg/m mg/m 3. Carbon Monoxide 8 hours** 5.0 mg/m mg/m mg/ m 3 - Non Dispersive (CO) Infra Red (NDIR) 1 hour 10.0 mg/m mg/m mg/m 3 Spectroscopy * Annual Arithmetic mean of minimum 104 measurements in a year taken twice a week 24 hourly at uniform interval. ** 24 hourly/8 hourly values should be met 98% of the time in a year. However, 2% of the time, it may exceed but not on two consecutive days Water Pollution Source of Water Pollution The sources of water pollution are: Effluent from ash disposal area Effluent from water treatment (WT) plant Steam generator blow down Cooling tower blow down Plant drains Effluent from coal pile area run off Recovered water from ash pond Section - 10 Page 9 of 24

219 Thermal Power Plant: Standards for Liquid Effluents Source Parameter Concentration not to exceed, mg/l (except for ph & Temp.) Condenser Cooling Water (once through higher cooling system) Cooling Tower Blow down Ash pond effluent ph Temperature* Free available Chlorine Zinc Chromium (Total) Phosphate Other corrosion inhibiting material on ph Suspended solids Oil & grease 6.5 to 8.5 Not more than 5 C than the higher intake Limit to be established on case by case basis by Central Board in case of Union Territories and State Boards in case of States 6.5 to As per Ministry of Environment the quality of effluent permitted to be discharged has been specified under the following categories. Inland surface water Public sewage Land for irrigation Marine Coastal areas For power plant purposes we will consider the category under inland surface waters. The major effluents limits are as follows S.NO Parameters Standards 1. Suspended Solids : 100 mg/l 2. Particulate size suspended solids : 850 micron 3. Temperature : Shall not exceed 5 0 C above the receiving water temperature Section - 10 Page 10 of 24

220 4. Oil and grease : 10 mg/l 5. Total residue Chlorine : 1.0 mg/l Temperature Limit for Discharge of Condenser Cooling Water From Thermal Power Plant New thermal power plants commissioned after June 1, New thermal power plants, which will be using water from rivers / lakes / reservoirs, shall install cooling towers irrespective of location and capacity. Thermal power plants which will use sea water for cooling purposes, the following condition will apply New Projects in Costal Areas using Sea Water The thermal power plants using sea water should adopt suitable system to reduce water temperature at the final discharge point so that the resultant rise in the temperature of receiving water does not exceed 7ºC over and above the ambient temperature of the receiving water bodies Existing Thermal Power Plants Rise in temperature of condenser cooling water from inlet to the outlet of condenser shall not be more than 10 C Effluent Recycle and Reuse System The waste water treatment system shall be designed to collect waste water from all sources in the power plant and provide treatment to enable it to be reused in the power plant to achieve ZERO DISCHARGE. The quality of effluent shall conform to the requirements of reuse. The sources of plant effluent are mainly: a) C.W. system blowdown b) Effluent from WT plant (Pre treatment, DM, UF plants) c) Coal pile area run off water d) Ash Water from ash pond e) Plant drains and boiler blowdown f) Sludge from various clarifiers / tube settlers g) Oily wastes from all transformer yard drains Section - 10 Page 11 of 24

221 h) Oily wastes from fuel oil unloading and tank farm areas i) Plant and Colony Sewage C.W system blowdown shall be utilised for meeting the requirement of ash handling system (such as fly ash conditioning, bottom ash disposal, refractory cooling etc) Coal handling system (dust suppression), plant service and fire protection system. Excess CW blow down, if any shall be led to the Central Monitoring Basin (CMB) after suitable treatment. During execution, the design shall ensure the quality of water at the CMB for horticulture / service purpose as per MoEF/PCB norms. Water treatment plant effluent comprises mainly of DM & CPU regeneration waste. These effluents shall be pumped to the ash disposal area after neutralisation. Alternatively, this effluent can also be led to the CMB. The drains from the coal handling area run-off shall be led to a settling tank. Coal particles shall settle down in the settling tank and the clear water from this shall be pumped to the CMB after suitable treatment. Plant drains from SG/TG areas shall be led to a sump which shall also collect oily wastes from transformer area and fuel oil farm area. These oily effluents shall be further treated in an oil water separator for removal of oil traces. The clear water shall be led to the CMB after treatment process and the dirty oil shall be disposed off in drums separately. Clarifier sludge system shall undergo a complete solid waste management concept. Separated solids after thickener / centrifuge / filter press mechanisms shall be disposed off manually. The CMB shall have two (2) compartments with each compartment having adequate storage to collect a day s effluents (minimum capacity of CMB shall be as per enclosed water system scheme). Facilities in the form of chemical dosing system, effluent recirculation system, ph correction, etc shall be provided to treat the effluent and bring the quality suitable for reuse. The treated effluent should be utilised as far as possible for horticulture, service water, etc. Necessary instruments shall be provided for monitoring the quality of effluents. This system shall be complete with all pipes, valves, flow measuring devices and fittings etc. Section - 10 Page 12 of 24

222 A complete sewage treatment plant shall be provided to treat the sewage from the power plant and the colony. The sewage treatment plant shall be located inside the power plant. Dedicated sewage lines from each building shall be led to the sewage treatment plant. The plant shall consist of primary, secondary and tertiary treatment facilities. Final treated water shall be utilised strictly for horticulture only Guidelines for discharge point The discharge point shall preferably be located at the bottom of the water body at midstream for proper dispersion of thermal discharge. In case of discharge of cooling water into sea, proper marine outfall shall be designed to achieve the prescribed standards. The point of discharge may be selected in consultation with concerned State Authorities/NIO No cooling water discharge shall be permitted in estuaries or near ecologically sensitive areas such as mangroves, coral reefs / spanning and breeding grounds of aquatic flora and fauna Noise Pollution Source of Noise Pollution The sources of noise in a power plant are: Steam turbine generator Other rotating equipment Combustion induced noises Flow induced noises Steam safety valves Noise Pollution Indian Standards As per Ministry of Environment the limits in the noise levels for industrial areas are as follows AM PM PM-6.00 AM Noise level Leq 75 db (A) Leq 70 db (A) (at plant boundary) Section - 10 Page 13 of 24

223 Permissible Noise Levels Duration per Day (in hours) Sound Level db (A) Air Quality Monitoring Programme The purpose of air quality monitoring would be acquisition of data for comparison against prescribed standards, thereby ensuring that the quality of air would be maintained within the permissible levels. It is proposed to monitor the following from the stack emission: Suspended particulate matter Sulphur dioxide Nitrogen oxides For this purpose, it is proposed to acquire the following monitoring equipment: High volume sampler for monitoring particulate matter Sulphur dioxide monitor Nitrogen oxides monitor It is also proposed to monitor particulate emission qualitatively and quantitatively using a smoke detector on the stack and with the aid of a continuous particulate stack monitoring system. The stack monitoring data would be utilized to keep a continuous check on the performance of the ESP's Water Quality Monitoring Programme The monitoring schedule and parameters to be analysed in the effluent generated from various sources: Section - 10 Page 14 of 24

224 S. No Source of effluent Frequency of analysis Parameters for examination 1 Ash pond Weekly ph and suspended solids 2 Steamgenerator blow down 3 Cooling tower blow down Weekly Weekly ph, suspended solids, oil and grease, copper, iron Phosphate Impact of Pollution / Environmental disturbances : Since all necessary pollution control measures to maintain the emission levels of dust particles, sulphur dioxide and nitrogen oxides within the permissible limits would be taken and necessary treatment of effluents would be carried out. Hence, there would be no adverse impact on either air or water quality in and around the power station site on account of installation of the proposed power plant Environmental Management Plan Environmental Management Plan (EMP) is the key to ensure that the environmental quality of the area does not deteriorate due to the operation of the plant under study. This covers the management of the overall environmental issues including the requirement of capacity building for environmental management. Management plan consists of the following activities: i) Specific action plan for implementing mitigation measures ii) Monitoring of Environmental Quality iii) Rainwater Harvesting iv) Training v) Statutory requirements and Implementation vi) Documentation vii) Green Belt Plantation viii) Social Responsibility The different aspects of the Environmental Management Plan are discussed below: Section - 10 Page 15 of 24

225 Implementation Plan Mitigation Plan is the key to ensure that the environmental qualities of the area will not deteriorate due to the construction and operation of the project. The Mitigation Plan covers all aspects of the construction and operation phases related to environment. The mitigation plan needs to be implemented right from the conception and should continue till the end. Implementation of Environmental Mitigation measures is the most important task of EMP. The Plan can be divided into two phases: (a) During construction phase and (b) During operational phase. An implementation task list is formed and the important mitigation measures are included. The list also includes the time frame for implementation and also the responsibilities of the concerned authority. Important mitigation measures and the implementation schedule are as in below table Environmental Management Plan during Construction Phase Environmental Remedial Time Frame Responsibility component Measures Water Groundwater No extraction of ground water Throughout construction phase Supervising engineer Surface water No disposal of any Throughout Contractor, resources wastewater outside construction phase supervising engineer Drinking water Arrange water Throughout Contractor, requirement without affecting construction phase supervising engineer local requirement Waste water from Ensure proper Throughout Design consultant, workers camp sanitation and construction phase contractor, Section - 10 Page 16 of 24

226 Environmental Remedial Time Frame Responsibility component Measures drainage. No direct supervising engineer discharge in water bodies or the rivers / nullahs Air & Noise Dust generation Spraying of water Throughout Contractor, wherever required construction phase supervising engineer Gaseous emission Ensure checking of Throughout Contractor, from construction vehicular emission construction phase supervising engineer work vehicles and obtaining pollution under control certificate Noise from Ensure machineries Throughout Contractor, machineries and meeting noise level construction phase supervising engineer construction standards Land Land development Preserve the excavated topsoil to be used for green belt development Throughout construction phase Design consultant, contractor, supervising engineer Solid waste from Ensure dumping at Throughout Design consultant, construction work pre selected construction phase contractor, location supervising engineer Others Occupational health Ensure necessary facilities according to factories act Throughout construction phase Design consultant, contractor, supervising engineer Section - 10 Page 17 of 24

227 Environmental Management Plan during Operation Phase Environmental Component Remedial Measures Time frame Responsibility Wastewater No discharge of untreated waste water outside the plant Throughout Operation Phase Manager Environment Gaseous Emission Pollution Control Throughout Manager Equipments and Operation Phase Production and Dispersion Manager through stack Environment Air Quality Regular Monitoring Throughout Manager according to schedule Operation Phase Environment Emission Quality Regular Stack emission Throughout Manager monitoring according to Operation Phase Environment schedule Water Quality Monitoring of wastewater quality before and after Discharge Ground water around ash pond monitoring Throughout Operation Phase Manager Production and Manager Environment Noise All machineries would Throughout Manager follow relevant noise Operation Phase Environment regulations. Regular Monitoring according to schedule Solid Waste Disposal at pre selected Throughout Manager site Operation Phase Production and within the plant Manager premises and in ash Environment Section - 10 Page 18 of 24

228 Environmental Component Remedial Measures Time frame Responsibility pond Safety Maintain all safety Throughout Manager provisions Operation Phase Production and Manager Environment Statutory Meet all Statutory Throughout Manager Requirements Requirements within Operation Phase Production and time Manager schedule Environment Monitoring of Environmental Quality The success of environmental control measure can only be understood by proper monitoring of the environmental parameters. A detailed monitoring for different environmental parameters will be carried out as per direction of Tamil Nadu Pollution Control Board. Monitoring methodologies will follow standard methods prescribed by Central Pollution Control Board (CPCB), Bureau of Indian Standards (BIS), USEPA, AWWA etc. Major monitoring parameters are discussed below. All monitoring reports will be submitted to Tamil Nadu Pollution Control Board Ambient Air Quality Ambient air quality will be monitored within the plant and in the vicinity as directed by Tamil Nadu Pollution Control Board. The parameters will include SPM, RPM, SO2 and NO2. The report will be submitted to Tamil Nadu Pollution Control Board. The sampling and analysis of air pollutants will be done as per the norms suggested by Central Pollution Control Board (Emission Regulations Part-III) and also the Bureau of Indian Standards IS Section - 10 Page 19 of 24

229 Stack Emissions Emission from boiler stack will be monitored monthly or as directed by Tamil Nadu Pollution Control Board. The results will be analyzed to find out whether those are meeting the required level. PM, SO2 and NOx and gas flow will be monitored. Online automated stack monitoring equipment s will be installed for monitoring of stack emissions. Stack of 275 m shall be provided for coal fired boilers for better dispersion of pollutants. Electrostatic precipitators of 99.9% efficiency shall be provided for the coal fired boilers Noise Monitoring Construction Phase The impact of noise due to construction activities are insignificant, reversible and Localized in nature and mainly confined to the day hours. Operational Phase All rotating items shall be well lubricated and provided with enclosures as far as possible to reduce noise transmission. In general, noise generating items such as fans, blowers, compressors, pumps, motors etc. are so specified as to limit their speeds and reduce noise levels. Operators will be provided with necessary safety and protection equipment such as ear plugs, ear muffs etc.; Provision of green belt in and around the plant premises. Noise monitoring will be carried out inside the units near the high noise generating areas once in a month. Ambient noise monitoring just outside the plant limit will be conducted monthly. Noise levels monitored will include Leq day & night, Lmax, and Lmin Water Quality Construction Phase The impact on water environment during construction phase is likely to be short term and insignificant. Section - 10 Page 20 of 24

230 Operational Phase Water quality at the discharge point from CMB will be monitored everyday for the relevant parameters as mentioned for Thermal Power Plants. Water quality near the discharge point will be monitored monthly. More parameters or locations may be included for monitoring if directed by Tamil Nadu Pollution Control Board. The sampling and analysis methodologies of the water samples will be as per IS- 2488, IS-3025, APHA 20th Ed etc Quality Assurance A quality assurance plan should be developed which will include all references methods for monitoring, relevant analytical techniques, calibration of equipment, standard of reagents, collection and presentation of results etc. All monitoring activities will be reviewed to find out the implementation of all the required norms. Periodic environmental audit may be arranged to make quality assurance a success Periodic Preventive Maintenance All pollution control, monitoring and safety equipments shall be periodically checked and calibrated Safety & Health Periodic monitoring of the health of the workers will be carried out as required by Factories Act. For safety, mock drill of the concerned employees for handling the emergency situation will be carried out, as a part of On-Site Emergency Plan. Air Quality at the work place will be measured intermittently Green Belt Development There will be all efforts for improving the environmental quality of the plant complex through tree planting in organized manner. The trees will be planted inside the plant in vacant areas, along the boundary walls in rows to develop wide green belt and also in dust- prone area i.e. Coal yard, ash pond along with vacant area for landscaping including gardening. There is about 155 acres of land for greenery development. This large tract of land will be vegetated and plantation will be developed and the area will turn to be a large green park. The predominant species list for greening is as follows: Section - 10 Page 21 of 24

231 Acacia auriculaeformis (akasmoni), Alstonia scholaris (chatim), Cassia fistula (bandarlathi), Lagerstroemea parviflora (jarul), Terminalia catappa (kath badam), Spathodea campanulata (spathodea), Grevellia robusta (silver oak), Delonix regia (gulmohar), Peltophorum pterocarpum (radhachura), Gmelina arberea (gamar) etc. Green belt plan is shown in the Layout Plan Rainwater Harvesting Rainwater harvesting is now an important component of wise resource use and environmental management. During operation of the plant following approach will be taken to implement the Rainwater harvesting plan. Rainwater from the roofs of all the Station Buildings of the units, storm water drains adjoining the roads of Cooling Towers, ESP / Boiler areas of the plant shall be collected in a rainwater collection tank. All storm water drains of the main plant area shall be connected to the rainwater collection tank. Rainwater collected in the rainwater tank is to be utilised for further use. This is achieved by installing a suitable pump at one end of the tank. This shall pump the collected water to the synthetic PVC tank installed on the roof of superstructures like Station Building, etc. The size of the synthetic tank shall be suitably sized based on the rainfall intensity and the runoff there-of. Additional tanks could be installed as and when the underground tanks are added. PVC pipe is proposed for pumping water from the rainwater collection tank to the tanks on top of the buildings. Collected water from the synthetic tank is distributed by gravity to desired locations for nonpotable use like gardening, cleaning etc. Excess water will be discharged through CMB Training Training is of much importance in environmental management. Environmental science is a developing subject and the people implementing environmental strategies should remain up to date with the environmental control processes. The person in charge of the environmental jobs should attend suitable training courses. Besides, there shall be training programme for the general employees at different level Statutory Requirements and Implementation Each industry needs to meet a number of statutory requirements under Water (Prevention & Control of Pollution) Act; Air (Prevention & Control of Pollution) Section - 10 Page 22 of 24

232 Act; Environment (Protection) Act; Hazardous Waste (Management & Handling) Rules; Manufacture, Storage and Import of Hazardous Chemicals Rules etc. Company has also to submit yearly Environmental Statements. Environment Management plan will ensure that these entire statutory requirements are met in time Documentation Documentation is an important step in implementing Environmental Management Plan. All statutory norms should be kept at one place for quick references. All monitoring results should be kept at selected folders which can be easily accessed. The presentation of the results should also be planned. Graphs and diagrams can be used to show the trend in environmental quality or achievement. Documents should be kept at a declared position. Documentation will include Major technical information in operation Organizational Charts Environmental Monitoring Standards Environmental and related legislation Operational Procedure Monitoring Records Quality Assurance Plan for Monitoring Emergency plans Social Aspects During Construction, the project will provide employment to local personal. During the operational phase also, the project will generate employment opportunity. Increase in employment opportunities and reduction in migrants to outside for employment, Increase in literacy rate, Growth in service sectors Increase in land prices, house rent rates and labour wages, Improvement in socio cultural environment of the study area Improvement in transport, communication, health and educational services, Increase in employment due to increased business, trade commerce and service sector Social Welfare Schemes under Corporate social Responsibilities (CSR) will be taken up based on need based assessment studies covering as area of Section - 10 Page 23 of 24

233 10KM radius of the project site. About 0.04% of the project cost will be earmarked fro this purpose Environmental Management Cell A separate environmental management cell should be established to implement the management plan. The cell shall report to the Plant manager. The cell shall ensure the suitability, adequacy and effectiveness of the Environment Management Programme. The management review process will ensure that the necessary information is collected to allow management to carry out its evaluation. This review will be documented. Section - 10 Page 24 of 24

234 Section 11 Execution and Project Management Construction Facilities Requirement The proposed 2 x 800 MW power station is to be located at Ash dyke of NCTPS, Village Vayalur, District - Thiruvallur, Tamil Nadu. Adequate construction facilities such as office, stores, sheds etc. will be provided for the successful & timely implementation of the plant. All roads whether connecting to site and within the plant area will be constructed to enable the transport and movement of plant and construction equipments, machines, tools & tackles. Covered area for storage of equipments will be provided. The construction work force for the proposed power station will be accommodated within the vicinity of the plant. The estimated construction power for construction of the plant is about 3000 KVA. The required construction power supply will be made available from the nearby existing substation. A DG set of adequate size will also be provided as standby arrangement for power supply at site for the construction phase of the power project. The water required during construction is estimated at 200 Cu.m/day and will be met from suitable ground water source till water system is established alternatively. Raw materials for the construction of the proposed station such as stone aggregate, conforming to IS-383 and sand free of silt meeting the requirements of IS-650 will be obtained from nearby area. Cement will be available from Cement Plants in the State. Steel will be made available from the nearest steel stockyard Execution Methodology The proposed 2 x 800 MW power project can be executed in two modes: Case I : Cost plus (Single EPC) without finance Case II : Tariff based bidding Section - 11 Page 1 of 7

235 Cost plus (Single EPC) Vs Tariff based bidding In case I of Cost plus (Single EPC) without finance, TANGEDCO has to arrange finance from the board / other institution and executing the project by preparing EPC specifications and inviting bids from EPC contractors who will take care of the complete design, manufacture, supply & construction works on turnkey basis. After commissioning, the contractors will handover the plant to TANGEDCO. Whereas in case II of tariff based bidding, TANGEDCO will give the land only for construction of plant and a developer will execute the complete project. The developer will be selected by competitive bidding i.e. whoever offers lowest tariff for the supply of 2 x 800 MW over a period of 25 years Comparison of Tariff based bidding with Cost Plus (Single EPC) bidding S.NO Tariff based bidding Cost Plus (Single EPC) bidding 1. The price computed is comparatively less than cost plus basis 2. Sizable portion of subsequent increase in borne by the supplier (project developer) The price computed (even comparatively) are higher Subsequent increase in tariff is passed on to the Consumer TANGEDCO is to generate the power and distribute the power and not going to sell power to the third Party. Hence there is no need for going on tariff based bidding. The power plant may be put on EPC basis through ICB (International Competitive Bidding) by which TANGEDCO can select the best efficient and reliable equipments at competitive rates from reputed vendors. The power project also can come up faster with direct involvement of TANGEDCO. Tariff based bidding will have all the commercial condition for the increase of tariff over a period of time based on variable cost like escalation in fuel etc which will not be reflected during the initial period. Hence all infrastructures available with TANGEDCO for project implementation, we recommended TANGEDCO to go for an EPC mode is for the implementation of the proposed power project of 2 X 800 MW Procurement Procedure The project will be divided into a number of packages for implementation. Supply and erection of a 2 x 800 MW units consisting of the following major items and packages are briefly described below: Section - 11 Page 2 of 7

236 Mechanical a) Steam turbine & generator with all associated auxiliaries such as Boiler feed pumps, condensate pumps, condenser, feed water heaters, deaerator, heat exchangers and controls. b) Steam generator and associated auxiliaries with draft system, Coal preparation and firing system, fuel firing system Electrostatic precipitators complete with ducting and electricals. c) Supply and erection of Coal handling system/plant. d) All associated piping, valves and fittings including PRDS. e) Supply and erection of service and instrument air compressors & dryers. f) Supply and erection of circulating water pumps/miscellaneous pumps g) Supply and erection of ash handling system/plant. h) Supply erection of cooling towers. i) Supply and erection of Raw water intake system, clarifiers, filtration plant j) EOT crane & Hoists k) Workshop equipment, chemical lab equipment. l) Fuel oil storage and handling system. m) Supply and erection of air conditioning and ventilation system. n) Supply and erection of miscellaneous mechanical equipment such as pumps, tanks, vessels, piping, fittings fire and protection and detection system, portable fire extinguishers Electrical a) Supply and erection of electrical equipment such as transformers, switchgear, motor control centers, DC supply system including station earthing, lighting etc. b) Switchyard Equipment c) Power and control cables. d) Supply and installation of intercommunication/telephone system e) DG sets Control & Instrumentation Comprising of Control & Electronic panels, Alarm and annunciation & field Instrumentation and control systems. Section - 11 Page 3 of 7

237 Civil a) Construction facilities, piling, foundation, miscellaneous civil works, roads, building, pipe racks, b) Structural steel works c) Chimney d) Coal Handling System e) Ash Handling System f) Water intake system, filtered water storage facility An experienced Project Engineering Consultant will be engaged for the preparation of detailed engineering specification, evaluation of bids, package support engineering, interface engineering ensuring overall plant performance rendering assistance in Project Management etc Project Implementation Schedule A bar chart of the work schedule for the key milestone activities is shown in Dwg. No.CCE ME It has been developed considering the following: 1) The zero date has been taken as the day the main equipment packages viz. the steam generator, TG & their auxiliaries are ordered. 2) The Unit will be scheduled to 48 Months from the Date of Order and second unit will be commissioned after 6 Months. 3) The Erection, Testing & Commissioning of the units will be undertaken by a team of responsible, competent and efficient personnel to ensure that: The units will be made ready for operation in the shortest possible time and in no case should the scheduled time is exceeded. To reduce interest charges and unnecessarily large inventories will not be built up. The plant once installed will have a high reliability and availability. The timely design & construction of the main plant building housing the TG is important and will not be delayed on any account. Section - 11 Page 4 of 7

238 O & M Management It is envisaged that for normal operation and maintenance, the station will be headed by the Chief Engineer/Executive Director and day to day work of the station will be looked after by him. He will be assisted by senior executives under him who will hold independent charge of their departments and the functions. The operation of the station would be the overall responsibility of the Addl. Chief Engineer (Operation & Maintenance) who would directly report to the Chief Engineer/Executive Director. The total manpower requirement is presently estimated to 840 of which about 300 employees will be deployed for plant operation in keeping with the design and operating philosophy. The maintenance wing is envisaged to be headed by Addl. Chief Engineer (Operation & Maintenance) and would be assisted by Senior Executive in respective fields. Approximately 200 persons would be deployed in maintenance of plant and machineries. Various services like CHP, AHP, Water Management Vehicle, Cranes, workshop, Store etc. of the station shall be the overall responsibility of the Addl. Chief Engineer (Services) & would be assisted by Senior Executive in respective fields. Approximately 200 persons would be deployed to provide services for smooth running of the plant. The functions of administration, welfare, general services, medical, safety and security, training and miscellaneous maintenance is envisaged to be looked after by Superintending Engineer. He will have about 100 persons of various disciplines assisting him in carrying out the above functions. Finance, budget and audit is envisaged to be looked after by Senior Accounts Officer who would directly report to the Chief Engineer/ Executive Director. There will be about forty (40) persons deployed for this function. In arriving at the above estimates of manpower, it has been conceived that normal day to day maintenance works will be carried out by the regular staff. Additional manpower required for major overhaul / maintenance works periodically will be arranged through contract labour. Section - 11 Page 5 of 7

239 Considering all the above, tentative Project Organization Chart for construction & O&M are enclosed as Dwg. No. CCE ME and CCE ME Training For Coal fired plants of this capacity the adequate experience & expertise exists in the country. Training of O&M staff will be arranged through prevalent methods & practices which will include computerised plant operation, simulator, various audio visual cards, a well maintained library and requisite set up for training activity. A full fledged training department headed by Chief Engineer - Human Resource Development (HRD) is to be implemented. The responsibility of the Training Department is to look after the training of technical and management trainees, supervisor trainees, trade apprentices etc. to replenish the requirements of trained personnel. In case of new recruits who do not have appreciable exposure to power station practices, the training programme will include: a) General theoretical training in power station operation and maintenance. b) Actual in-plant training in the operating stations of power generating plants. In case of the personnel, who will be deputed from the existing cadre of the project authorities and direct recruits with previous power station experience the above mentioned training is not required. If required, the personnel will be sent for training in Power Training Institutions of CEA or other authorized institutions for the same time to time. The training programme for finalization with the new station will vary with the nature of duties. Maintenance personnel experienced in the maintenance of mechanical, electrical and control and instrumentation would be employed and posted at the construction site immediately after the major civil work is over so that they may be closely associated with the construction of all plant and equipment. The key operating personnel at thermal power plant training institute, if required, shall be provided lectures by supplier s engineers and drills for various operations may familiarize themselves with the new generating plant. All operating personnel would be actively associated with all phases of commissioning of plant. Section - 11 Page 6 of 7

240 Supervisory staff and senior officers are to be posted at the construction site about six (6) months prior to commissioning of the unit for familiarizing with the same. Qualified chemists of adequate experience in power plant operation is to be deployed at work site at least three (3) months before the initial run so that they could set up a laboratory for water, coal and other testing. Section - 11 Page 7 of 7

241 Section 12 Clean Development Mechanism (CDM) Clean Development Mechanism The U.N. Framework Convention on Climate Change (UNFCCC) was adopted in June 1992 at the Earth Summit in Rio de Janeiro and the objective of the convention is to achieve stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. The adjunct to the Convention, the Kyoto protocol, was hammered out in December 1997, setting individual targets for developed countries to reduce yearly emissions of Green House Gases (GHGs) to a minimum of 5 percent below their 1990 levels in the first commitment period, India has ratified the Kyoto Protocol in The Clean Development Mechanism (CDM), one of the flexible mechanisms under the Kyoto Protocol encourages development of Green house gas emission reduction projects in developing countries like India for achieving sustainable development and also earns carbon credits. The amount of carbon emission saved by such project is required to be certified by the CDM Executive Board. The certificate specifying carbon reduction in tones can be sold to developed countries which are signatories to the protocol. One tonne of carbon di-oxide reduced through Clean Development Mechanism project in a developing country when certified by the CDM Executive Board becomes a tradable CER (Certified Emission Reduction) What is CDM? To get a project registered under CDM, it has to run through an approval procedure, including the host country approval & validation, administered by the UNFCCC. The Ministry of Environment and Forests (MoEF), GoI is the Designated National Authority (DNA) in India for according host country approval. A CER is given by the CDM Executive Board to projects in developing countries to certify they have reduced green house gas emissions by one tonne of carbon dioxide per year. One CER is equivalent to one tonne of carbon dioxide reduced Section - 12 Page 1 of 8

242 A project is eligible for CDM benefits if the project will result in a net decrease in green house gas emissions this is called additionality. If a project gets 20,000 CER s it means that it s emissions are 20,000 tonnes of carbon dioxide less than a reference point called a baseline. Project Activities under CDM must be: Hosted by non-annex I Parties (like India) that have ratified the Kyoto Protocol and established a Designated National Authority (DNA). Developed by public or private entities authorized by the relevant host Party and Annex I Party (like U.K.) involved in the project activity. Validated by a Designated Operational Entity (DOE) in accordance with the CDM project eligibility and participation requirements. Registered by the CDM Executive Board after review by a Registration and Issuance Team to ensure compliance with the international rules; and Once commissioned and operational, verified and certified by a DOE as resulting in real, additional, measurable and verifiable reductions in greenhouse gas emissions below usual baseline scenario Methodology Methodology is applicable to: Only new electricity generation plants using more efficient power generation technology Section - 12 Page 2 of 8

243 The baseline fossil fuel is used in more than 50% of total generation Availability of data on fuel consumption and generation of the power plants Applicable to new coal based generating units with supercritical parameters (More Efficient Technology) Supercritical technology efficiency is about 2% higher than conventional technology (Sub Critical technology) CDM Project Cycle Project s contribution to Sustainable Development It is the prerogative of the host Party to confirm whether a clean development mechanism project activity assists it in achieving sustainable development. The CDM projects should also be oriented towards improving the quality of life of the poor from the environmental standpoint. Following aspects should be considered while designing CDM project activity: Social well being The CDM project activity shall lead to alleviation of poverty by generating additional employment, removal of social disparities and contribution to provision of basic amenities to people leading to improvement in quality of life of people Economic well being The CDM project activity should bring in additional investment consistent with the needs of the people. Section - 12 Page 3 of 8

244 Environmental well being This shall include a discussion of impact of the project activity on resource sustainability and resource degradation Technological well being The CDM project activity shall lead to transfer of environmentally safe and sound technologies that are comparable to best practices in order to assist in upgradation of the technological base Baseline Emission Calculations Baseline emissions (BE) are calculated by multiplying the electricity generated in the project plant (EG) with a baseline CO 2 emission factor (EF) as follows: BEy = EGy * EFy Where BEy Baseline emissions in year y (tco2) EGy Quantity of electricity generated in the project plant in year y (MWh) EFy Baseline emission factor in year y (tco2/mwh) As per methodology, only CO 2 emissions from fossil fuel combustion in the project are to be considered. The emission factor of the technology and fuel identified as the most likely baseline scenario is calculated as follows: EF = MIN (EF BLF, EF PJF, ) *3.6 GJ/MWh η BL Where EFy Baseline emission factor in year y (tco2/mwh) EF BLF baseline emission factor of the baseline fossil fuel type that has been identified as the most likely baseline scenario (tco2 / Mass or volume unit) EF PJF - Average CO2 emission factor of the fossil fuel type used in the project plant in year y (tco2 / Mass or volume unit) Section - 12 Page 4 of 8

245 η BL is the Energy efficiency of the power generation technology that has been identified as the most likely baseline scenario Emissions Trading An emission trading is a market based system that allows firms the flexibility to select cost effective solutions to achieve established environmental goals. Emission trading will allow countries and individual companies to buy and sell carbon created by activities that reduce the level of Green House Gas emissions. Since carbon dioxide is the principal greenhouse gas, people speak simply of trading in carbon. Carbon is now tracked and traded like any other commodity. This is known as the "carbon market." Carbon credits are traded at CO 2 exchange in UK, European Climate Exchange, Chicago climate Exchange (CCX) and Multi Commodity Exchange (MCX) in India CERC Regulations for sharing of CDM benefits The proceeds of carbon credit from approved CDM project shall be shared between generating company and concerned beneficiaries in the following manner namely: 100% of the gross proceeds on account of CDM benefit to be retained by the project developer in the first year after the date of commercial operation of the generating station. In the second year, the share of beneficiaries shall be 10% which shall be progressively increased by 10% every year till it reaches 50%, where after the proceeds shall be in equal proportion, by the generating company and the beneficiaries Reduction of CO 2 emissions (tentative) with the proposed 2 x 800 MW supercritical thermal power plant The efficiency of the super-critical coal fired power plant is around 41% (assumed) and station heat rate considered as 2100 kcal/kwh for the proposed project. 3.6% is the conversion factor for coal GCV to NCV as per CEA. Section - 12 Page 5 of 8

246 The project emissions and total emission reduction table would be as below: Project Emissions Year Coal FC Blended Conversion NCV Emission PEy required GCV factor from factor GCV to NCV ton/mwh ton Kcal/kg % Kcal/kg tco 2/MWh tco 2 Jan 2012 Dec Jan 2013 Dec Jan 2014 Dec Jan 2015 Dec Jan 2016 Dec Jan 2017 Dec Jan 2018 Dec Jan 2019 Dec Jan 2020 Dec Jan 2021 Dec Total Emission Reduction Year Baseline Emission Project Emission Emission reduction tco 2 tco 2 tco 2 Jan 2012 Dec Jan 2013 Dec Jan 2014 Dec Jan 2015 Dec Jan 2016 Dec Jan 2017 Dec Jan 2018 Dec Jan 2019 Dec Jan 2020 Dec Jan 2021 Dec Total Section - 12 Page 6 of 8

247 Capacity MW Baseline emission factor Reduction in tonnes CO 2 Emission for 1 st year CDM Revenue for 1 st 1CER = Euro 12.0 (Dec 2010) 1 Euro = Rs Reduction in tonnes CO 2 Emission from 2 nd year up to 10 th year CDM Revenue from 2 nd year up to 10 th 1CER = Euro 12.0 (Dec 2010) 1 Euro = Rs x 800 MW tco 2 /MWh = Euros = ~ Rs crores = x 9 years = = 284,057, Euros = ~ Rs crores CDM Revenue for 10 = ~ Rs = ~ Rs crores 1 CER = Euro 12.0 (source: European Climate Exchange) CER Spot market price in Mumbai, India as on : CER = Rs. 702 per MT (source: Multi Commodity Exchange of India Ltd) Benefits of CDM Benefits to Developed Countries Reduction in emission mitigation costs More flexibility for meeting their commitment Market for new and advanced technologies New investment opportunities Benefits of CDM to Developing Countries New source of foreign Investments Transfer of technology and expertise Employment generation & Infrastructure development India s Position No obligation to reduce emissions Section - 12 Page 7 of 8

248 Per capita Carbon dioxide emission of India is amongst the lowest in the world. Country India USA U.K China World Per capita CO 2 emission (tonnes of CO 2 /annum) TANGEDCO intends to construct a new supercritical coal fired power project of capacity 2 x 800 MW with CDM intent, at Ash dyke area of NCTPS. Adopting Supercritical technology results in enhanced plant efficiency resulting in reduced coal consumption. The specific CO 2 emissions per MWh of generated electricity of a new supercritical coal fired power plant are lower than the emissions of the existing sub critical power plants operating in India. Thus the implementation of a new supercritical coal fired power project contributes to the overall reduction of greenhouse gas emissions making it eligible under CDM. The methodology for such projects has already been approved by the CDM Executive Board vide ACM Hence, this project can generate tradable carbon credits under CDM thus improving the financial viability of the project. Section - 12 Page 8 of 8

249 Section 13 Project Cost Estimate Cost Estimate: The cost of generating one kwh of electrical energy by the proposed 2 x 800 MW unit has been calculated with the following assumptions:- 1. The cost of coal has been taken as Rs.2600 per MT for Indian Coal, Rs.4000 per MT for Imported coal and % per year thereafter. The cost of fuel oil is considered as Rs.35, 000/- per ton. 2. The annual plant load factor (PLF) has been taken as 85% once the system has stabilized after commissioning. (However, the plant loading most of the time will be 100%). 3. The plant auxiliary consumption has been taken as 6%. 4. The weighted heat rate of the plant has been taken as 2100 kcal / kwh. 5. Gross calorific value of Indian coal has been taken as 3800 kcal/kg, imported coal as 5500 kcal/kg, blended coal (70:30) as 3820 kcal/kg, blended coal (30:70) as 4780 kcal/kg. 6. The Tariff calculation has been calculated based following Central Electricity Regulatory Commission (CERC) conditions dated 19 th 2009: Jan a. Annual Fixed Cost: i. Return on Equity (RoE) RoE is calculated on pre-tax basis at the base rate of 15.5%. Rate of pre-tax RoE = Base rate / (1-t) Minimum Alternate Tax (t) = % RoE = 15.5 / ( ) = % ii. Depreciation The Residual value of the asset is considered as 10% and depreciation shall be allowed upto maximum of 90% of capital cost of the asset Section - 13 Page 1 of 8

250 Depreciation is calculated annually over the useful life of the asset at the rated specified below Useful life of the Thermal power station = 25 years Depreciation Rate for first 15 years = 4.67% Depreciation rate for remaining life = 2% The generating station which are in operation for less than 15 years, the difference between the cumulative depreciation recovered and the cumulative depreciation arrived by applying the depreciation rates corresponding to 15 years, shall be spread over the period upto 15 years, and thereafter the depreciation shall be recovered at the rates for remaining useful life after 15 years. For the proposed project in operation more than 15 years, the balance depreciation to be recovered shall be spread over the remaining useful life. Depreciation shall be chargeable from the first year if commercial operation. In case of commercial operation of the asset for part of the year, depreciation shall be charged on pro rata basis. iii. Interest on Working Capital: Two (2) months for generation corresponding to normative annual plant availability (considering non-pit head thermal generating station). Operation & maintenance (O&M) expenses for one month. Maintenance 20% of Operation and maintenance expenses. Receivable charges equivalent to two months of capacity charges and energy charges for sale of electricity calculated on normative annual plant availability factor. iv. Operational and Maintenance expenses (Rs. in Lakhs per MW) Operational and maintenance expenses is considered as Rs lakhs per MW based on the following conditions Section - 13 Page 2 of 8

251 Year 200/210/25 0 MW sets 300/330/350 MW sets 500 MW sets 600 MW & above sets The 25 years of useful life for Thermal power plant operation is considered. Initial Spares is capitalized as a 2.5 % of the original project cost. Debt equity ratio is considered as 80:20. Interest rate for loan is considered as 11.00%. Interest on working capital is considered as 10.00% The estimate has been made under three broad heads namely Mechanical, Electrical, C&I and Civil are based on current price data available with Consultant, budgetary offer from reputed manufacturers. The detailed Cost Estimate and Financial analysis (package cost, IDC, tariff calculation) are enclosed as Annexure 13.1, 13.2, 13.3, The following assumptions have been made in the preparation of the cost estimates:- 1. Cost of development for plant approach road, bridge has been considered. 2. Raw water (Sea Water) in take system from NCTPS Stage II with pumps, equipment & pipelines of length about 5 kms. 3. Fuel is available within a distance of approx 06 Kms from coal berth. 4. Freight, insurance have been taken as 2%. 5. Service Tax considered as 10.3% 6. Contingencies considered as 3.0% 7. Customs duty on Imported equipments taken as 23.89% 8. Erection, testing and commissioning has taken 9% of the equipment cost. Section - 13 Page 3 of 8

252 9. Cost of temporary construction facilities including consumables used during construction has been included. 10. The cost of mechanical packages, electrical and C&I packages are exclusive of CST, excise duty/custom duty. 11. Taxes and duties have been considered separately for total project cost and customs duty is for imported equipments have been considered. 12. Provision has been made for cost escalation of fuel. 13. Cost of transmission line of 400 KV single circuits / Double circuit is not considered. 14. Total Project cost, cost of generation and tariff for proposed power plant is given below General Breakdown of Project Cost Sl. No Land and Site Development Description Preliminary cost Rs. Crores 1a 1b 1c 1d 1e Land for proposed power plant (Total 500 acres) under the 1.00 Crore / acre Land under possession of TANGEDCO for ash disposal (Total crores / acres Rehabilitation and Resettlement Development of green belt Site development, preliminary expenses such as survey & soil investigation, Consultant for DPR preparation, engineering consultancy etc. Sub Total (Land and Site Development) of Sl.No Section - 13 Page 4 of 8

253 Sl. No Civil Works Description Preliminary cost Rs. Crores 2 Complete Civil Works for Proposed Power Plant Sub Total Civil Works (Sl. No.2) Plant & Machinery Mechanical 3 Steam Generator / Boiler Island 4 Steam Turbine Generator Island 5 Mechanical BOP Sub Total Sl.No 3 to Plant & Machinery Electrical and C & I 6 Electrical incl. Switch yard & Control and Instrumentation 7 Sub Total (Plant and Machinery both Mech. Elect and C & I ) 8 Initial Spares at 2.5% (item 7) 9 Total Taxes and Duties 10 Customs duty on Imported 23.89% for a CIF value of Rs.1611 Cr 11 Excise 10.0 % on Indigenous Equipments 12 CESS on 3% on ED Section - 13 Page 5 of 8

254 Sl. No Description 13 CST on indigenous 2% on Indigenous Equipments 14 Transportation & Insurance on 2% Preliminary cost Rs. Crores Erection, commissioning and 9% on S. No Service 10.3%for Erection & Commissioning Sub Total (Sl. No 10 to 16) 18 Total Plant Machinery, Taxes and Duties 19 Excise duty & Customs duty draw back (hence Mega Power project ED & CD is not applicable) 20 Total Project Machinery Cost (Including Supply, erection & Commissioning, Taxes and excluding CD & ED) Land Development and Civil works [1 & 2] (excl. land & green belt) Service 4.12% for civil construction (Sl. No.2) % for above excluding land 5.06 Land cost Sub Total of above [Sl. No. 20 to 24] % on S. No Total Project Cost without IDC (Sl. No 25, 26) Cost per MW without IDC 5.73 Syndicate 0.4% & Upfront 0.1% on (Sl. No. 27) Total Project Cost without IDC including upfront fees & Bankers fees IDC Total Project Cost with IDC Cost per MW with IDC 6.97 Section - 13 Page 6 of 8

255 Cost of Generation S. No Project Cost Values Unit 1 Condition I (Blended Fuel 70% Indian + 30% Imported) a. GCV of Blended Fuel : 3820 Kcal/kg b. Cost of fuel : Rs per ton c. Cost of 85% PLF : Rs per unit d. Levellised 85% PLF : Rs per unit 2 Condition II (Blended Fuel - 30% Indian + 70% Imported) a. GCV of Blended Fuel : 4780 Kcal/kg b. Cost of fuel : Rs per ton c. Cost of 85% PLF : Rs per unit d. Levellised 85% PLF : Rs per unit Condition III (100% Indian Coal) : a. GCV of Indian coal : 3800 Kcal/kg b. Cost of fuel : Rs per ton c. Cost of 85% PLF : Rs per unit d. Levellised 85% PLF : Rs per unit Condition IV (100% Imported Coal) a. GCV of Imported coal : 5500 Kcal/kg b. Cost of fuel : Rs per ton c. Cost of 85% PLF : Rs per unit d. Levellised 85% PLF : Rs per unit Section - 13 Page 7 of 8

256 Cost of Generation & Levellised Tariff for Indian Coal, Imported Coal & Blended Coal: Description Project Cost Cost of Generation Levellised Tariff Indian Coal Imported Coal Blended Coal (70% Indian + 30% Imported Blended Coal (30% Indian + 70% Imported Section - 13 Page 8 of 8

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259 Annexure 5.1 Location Map of Project PROPOSED SITE FOR 2 X 800 MW Annexure 5.1 Page 1 of 1