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1 International Seminar On Environmental compliances in TPPs Issues and challenges 30 th January 2017 Presentation Title ( Arial, Font size 28 ) Meeting New MOEF Norms: Technological & Implementation Challenges for Utilities Date, Venue, etc..( Arial, Font size 18 ) Ramkrishna Gadre CP Tiwari

2 Content About Tata Power Company Leader in Technology adoption MoEF Norms: Present and Revised Challenges in Compliance to Specific water consumption Norm and Conversion of OTC to RTC System Challenges in Implementation of ZLD SPM abatement technologies and Implementation challenges FGD Technologies and Implementation challenges De- NOx Technologies and Implementation challenges Estimated Capital Expenditure and Time Required Impact on O&M Cost Summary Technological & Implementation Challenges India s largest integrated Power Company 2

3 About Tata Power Company India s largest integrated power company with presence across the entire value chain - fuel, fuel logistics, generation, transmission, distribution and power trading Founded in 1906 to supply power to Mumbai» First hydro plant commissioned in 1915» Set up thermal power plantsin Mumbai in 1960s Current installed generation capacity is in excess of 10,500 MW including Thermal (Coal, Gas, WHRSG), hydro, wind, solar etc. Out of the above coal based thermal generation capacity is about 6300 MW (Using Imported and domestic coal) India s largest integrated Power Company 3

4 Leader in technology adoption First UMPP (4000MW) using super critical technology Largest single location photovoltaic installation 3 MW (Mulshi) First 25 MW solar power plant in India 5 years First 800 MW supercitical thermal unit Largest Wind Turbine Generator 2 MW (Visapur) First Flue Gas De-sulphurization plant in India using Seawater First pump storage unit in the country of 150 MW Capacity First 150 MW thermal unit First First gas 500 MW insulated thermal switch unit gear Computerized grid control & energy management system 220 kv transmission lines in four circuit towers 220 kv Cable Transmission Network First to Introduce SCADA and Fibre Optic ground wire communication 45 years 4

5 MoEF Norms: Present and Revised Plant / Unit Year of Commissioning Parameters Present Norms (mg/nm 3 ) Revised Norms (mg/nm 3 ) CGPL (Coastal Gujarat Power Limited) 5x 800 MW 2012 and 2013 SPM NOX Not Specified 300 SOX Not Specified 200 Trombay Unit MW 1984 SPM NOX Not Specified 600 SOX * 200 Trombay Unit MW 2009 SPM Maithon Power Limited 2x525MW U U * Trombay station has a limit of 24 TPD of SO2. NOX Not Specified 300 SOX * 600 SPM NOX Not Specified 300 SOX Not Specified 200 5

6 MoEF Norms: Present and Revised for TPTCL units (Contd.) Plant / Unit Year of Commissioning Parameters Present Norms (mg/nm 3 ) Revised Norms (mg/nm 3 ) JojoberaUnit1to3 1x67.5and2x120MW U U U SPM NOX Not Specified 600 SOX Not Specified 600 JojoberaUnit4and5- U x120MW U SPM NOX Not Specified 300 AllOperatingUnits All units commissioned before Dec 2016 SOX Not Specified 600 Sp. Water (m3/mwh) Not Specified 3.5 Cooling Tower Not Specified Mandatory 6

7 Impacts of new MoEF Norms Compliance to Specific water consumption Implementation of Cooling tower (Conversion from Once through cooling (OTC) to Recirculation Type Cooling (RTC)) Zero Liquid Discharge (ZLD) compliance SPM abatement technology Implementation of Flue Gas De-sulphurisation unit (De- SOx technology) De- NOx technology (Implementation of SCR/ SNCR) 7

8 Challenges in Compliance to Specific water consumption Norm and Conversion of OTC to RTC System 8

9 Challenges - Compliance to Sp. Water Consumption Norm New MoEF norm doesn t differentiate between raw and seawater while indicating norm restricting the specific water consumption of the TPP Compliance to water consumption norm would be possible only for raw water based inland power plants In coastal power plant based on seawater once through cooling (OTC) system and SWFGD, the water requirement would be very highcompared to latest norm of 3.5 and 2.5 cum / MWh In a typical 500 MW unit employing seawater based OTCS and SWFGD, estimated specific water consumption will be as below: Sr. No Consumers (m 3 /h) 1 Circulating water system Service water Potable water 10 4 De-mineralized water 60 5 Total Intake quantity per MW (m 3 / MWh) Approx

10 Challenges - Compliance to Sp. Water Consumption Norm (Contd.) The typical water consumption for coastal thermal power plant using seawater for once through cooling and SW FGD would range between 130 cum/mwh and 145 cum/mwh as against the norms of 3.5 cum/mwh The probable options for these plants to reduce the water consumption up to normative levels can be as follows: Option-1: Conversion of existing OTC system to sea water based RTC system for condenser cooling + sea water FGD [OTC to Sea Water RTC + Sea Water FGD] Option-2: Conversion of existing OTC system to sea water based RTC system for condenser cooling + lime / limestone based fresh water FGD [OTC to Sea Water RTC + Lime / Lime Stone FGD] Option-3: Conversion of existing OTC system to fresh water based RTC system for condenser cooling + lime/limestone based fresh water FGD [OTC to Fresh Water RTC + Lime / Lime Stone FGD] 10

11 Option-1: OTC to Sea Water RTC + Sea Water FGD Post conversion to cooling tower based RCT system, seawater will be required CT Make-Up Seawater will be required for FGD System for scrubber and dilution requirement Cycle of Concentration (COC) of Seawater based RCT System will be 1.3 to 1.5 due to seawater quality limitations(high TDS and TSS/Turbidity). As a result, specific water consumption remains above 50 cum/mwh (including Seawater requirement for CT Make up and SW FGD) Due to make up water requirement of seawater based RCT System & FGD system, specific water consumption is much above the stipulated figure of 3.5 m3/mwh In option-1, it is not possible to restrict the specific Water consumption up to 3.5 m3/ MWh 11

12 Option-2: OTC to Sea Water RTC + Lime / Lime Stone FGD In case OTC system is converted to RTC system, seawater for FGD will have to be sourced separately (almost 60% to 65% of current cooling water requirement) Due to large seawater requirement for seawater based FGD, it may be explored to replace existing SWFGD with limestone based FGD system that requires comparatively less water Conversion of SW FGD into the lime based FGD would need additional space which would be difficult in brownfield project Lime based FGD would need higher O&M costs towards sourcing of feedstock (limestone) and operational costs for Limestone/gypsum handling system, limestone sizing, slurry preparation, gypsum dewatering/disposal, waste water treatment etc. Due to seawater based cooling tower (RTC system), the specific water consumption shall still be much higher than specific water norms. In option-2 also, it is not possible to restrict the specific Water consumption up to 3.5 m3/ MWh 12

13 Option-3: OTC to Fresh Water RTC + Lime / Lime Stone FGD Fresh water requirement for typical 500 MW unit for Option-3 will be as under: Sr No Consumers Consumption for 500 MW unit (m 3 /h) 1 Cooling tower make up Limestone FGD Cooling tower blow-down 3 Service water Potable water 10 5 De-mineralized water 60 6 Total Intake specific water quantity 3.33(m 3 /MWh) As hypothetical scenario, With fresh water based cooling towers and limestone based FGD, the specific water consumption for typical 500 MW unit may be restricted to 3.5 m3/mwh. However there are several technical challenges /constraints which needs consideration for this option 13

14 Option-3: OTC to Fresh Water RTC + Lime / Lime Stone FGD (Contd.) Conversion of Seawater based CW system into fresh water based RTC system would require additional fresh water to be sourced In case of coastal plants with water scarcity, fresh water for CW requirement would have to be generated through seawater desalination plant Desalination plant and lime/limestone based FGD shall also require additional land, infrastructure, increased aux. power consumption and additional CAPEX+OPEX. Layout constraints: Layout study in existing plants has revealed that installation of desalination plant + Cooling tower + Limestone FGD installation in brownfield projects would be highly unfeasible. In view of all the above limitations, option-3 seems to be challenging implementation especially in brownfield plants 14

15 Difficulties in Conversion of OTC to RCT system Conversion of existing OCT to RCT shall need major modifications like: CW piping modifications/ replacement Condenser modifications/ replacement CW pumps modification/ replacement Augmentation of electrical power supply due to increased Aux. power consumption Layout and Space constraints in installing Cooling tower & associated system Cooling tower implementation feasibility study at one of our coastal plant revealed that the current space is insufficient for locating cooling tower. Cooling tower installation shall need reclamation of marshy land covered with mangroves which would not be environment friendly Conversion of OTC to RCT System in existing Coastal Plant is not viable due to above reasons 15

16 Challenges in Implementation of ZLD (Zero Liquid Discharge) 16

17 Challenges in implementing ZLD in TPP Plant uses raw water for various purpose such as cooling water, service water, potable water etc Plant generates different types of effluent water having different types / concentration of contaminants, variations in flow rates, different frequency of generation of effluents etc. The zero liquid discharge condition (ZLD) for thermal power plant would need to recycle and reutilize these different effluents on continuous basis. It is necessary to consider the different scenarios of operating conditions such as: Monsoon/ non-monsoon condition, Wet/ dry mode of ash disposal, Variations in water requirement for coal handling, Water requirement for horticulture Effluent utilization opportunities Depending on the effluent water balance, the treatment scheme will have to be designed for treating of high TDS complex waste priority wise The high recovery treatment plant is one such good option (>95% recovery plant) 17

18 SPM abatement technologies and Implementation Challenges 18

19 Suspended Particulate Matter and its Challenges Options available for retrofitting of ESP to meet new norms Installing additional fields in the upstream/ downstream of ESP Increasing the height of ESP. Addition of pass parallel to existing ESP Challenges includes Layout constrain in addition of new field in the upstream/downstream of existing ESP. Replacement of ID fan may be required to suit the higher pressure drop across New ESP. Increase in height of ESP may require re-design of existing structure and foundation. The existing foundation details may not be available. Space constraint for addition of New Pass. 19

20 FGD Technologies and implementation Challenges 20

21 Overview of all different FGD technologies Wet FGD Uses Aqeous Limestone (Ca(OH) 2 ) in slurry form Dominantly used in Non- coastal power plants Dry FGD Uses Quick Lime (CaO) in dry powdered form Due to dry waste handling issues not much in use nowadays Sea water based FGD Makes use of Sea water, Best suited for coastal power plants FBC Boiler Lime is mixed with bed material and helps to absorb sulphur in furnace 21

22 Wet Limestone based Flue gas Desulphurization 22

23 Difficulties in Installation of Wet Limestone FGD: Area within existing & Layout Constraints: Substantial footprint required for facilities like limestone handling/storage, gypsum handling/storage, slurry preparation system, gypsum dewatering system, waste water treatment plant etc. Absorber tower and GGH need space close to chimney which becomes difficult if no sufficient space is provided in original layout. Sourcing and Logistics of Limestone: The plant would need access to the limestone on continuous basis for the operation of FGD. The same may be constrained in many areas due to logistical issues / availability issues(for 1000 MW limestone requirement would be approx. 300 TPD) Disposal of gypsum: Huge quantity of Gypsum will be generated on a daily basis that would need large storage pond and evacuation facility (For 1000 MW Gypsum generated daily would be approx TPD) Waste water treatment: The waste water from limestone FGD would require the treatment system to effectively treat the effluent and maintain ZLD for plant. Increase in Aux. power requirement (approx. 1.5%) and may need major augmentation in electrical power supply system to meet this Aux power requirement Increased OPEX: The plant OPEX will increase substantially due to increased costs towards limestone sourcing etc. (Approx. 40 crs. per annum. for 1000 MW plant). 23

24 Dry Lime based Flue gas Desulphurization 24

25 Difficulties in installation of Dry Lime based FGD Area within existing layout: Dry Lime FGD faces similar issue of space availability in existing plant layout especially older plants where sufficient space not provided in original layout. Based on the recent reports, Generation capacity of around 90 GW (430 units) is facing problem due to non-availability of space for FGD. Sourcingandlogisticsoflime:The sourcing of lime will be issue in many areas. Byproduct utilization will be challenge High cost of reagent: Lime is costlier than Limestone, hence usage may be limited to smaller plant capacities only. Increase in Aux. power requirement (approx. 0.5 to 1%) and may need major augmentation in electrical power supply system to meet this Aux power requirement 25

26 Seawater based Flue gas Desulphurization (SWFGD) 26

27 Sea Water based FGD Technology Sea water by nature is alkaline with ph around 8.0 to 8.3. It contains an excess of calcium & sodium carbonates in solution. Theses components gives seawater a substantial capacity to absorb and neutralize SO 2 from flue gases. Only Seawater and air is used in the process, no chemicals/ special materials required No secondary waste products generation and hence no disposal issues The FGD outlet seawater is treated (dilution/ aeration) before discharge so as to meet the general effluent discharge norms. The absorbed SO 2 is transferred into sulphateions, which is natural constituent of sea water for marine environment. The acidic nature of the scrubber water is mainly because of absorption of CO 2 and SO 2. On aeration the dissolved CO2 escapes out. This together with oxidation of S03 and HC03 brings back the ph & O 2 of the scrubber water very close to its original value. 27

28 Challenges in installation of new SWFGD Area within existing layout: The installation of seawater FGD needs substantial footprint for scrubber tower and auxiliary systems, seawater supply and seawater treatment scheme etc. Sourcing of seawater: Seawater for FGD requirement is usually about 20-25% of total CW flow rate of the unit. In case of OTC system based on seawater it would be possible to tap it from CW outlet by suitable means. It will be furthermore difficult to source seawater in case plant switches to seawater based RTC system. The same may require separate FGD seawater pumping scheme. Treatment of FGD outlet seawater: The seawater treatment needs elaborate system for dilution and aeration. Construction of the dilution and aeration basin alongside the existing outfall channel/ seal well and its connection would be challenging task. In case of seawater based RTC system, the seawater for dilution will not be available and the process may need chemical dosing for ph correction. Variations in requirement of scrubbing water, Dilution and Aeration scheme depending on the technology provider makes it difficult to plan the scheme/layout/costing in advance prior to order finalisation 28

29 Other technological challenges in implementing FGD Flue gas duct design: Difficulty in duct modifications in older plants including GGH inlet / outlet ducting Design of dilution basin/aeration basin and it s interconnection with existing CW channel/ seal well in SWFGD: It may require the temporary diversion of the CW outfall channel CFD modelling/ physical modelling study would be required for hydraulic design Outage requirement: Implementation of FGD would require approx. 1 to 4 months outage Chimney lining of stack post FGD- To avoid the corrosion at lower flue gas temperature chimney shall require the acid proof lining Liningactivity may need longer outage (> 3 to 4 months) Vendor specific changes in the seawater requirement for scrubbing and dilution makes it difficult to plan the scheme/layout/ Overall Project Cost estimate prior to bidding 29

30 De- NOx Technologies and Implementation Challenges 30

31 NOx Generation & Available De-NOx Technologies NOx Type Fuel NOx Thermax NOx Source: NOx formed from Nitrogen in the Fuel. NOx formed from N2 in the Combustion Air. Formation Sensitive to: Oxygen Availability Fuel Nitrogen Content Kinetics Furnace Temperature Oxygen Availability Proportion 60% - 80 % 20% 40 % Technologies available for NOx abatement: Combustion Technology SNCR (Selective Non Catalytic Reduction) SCR (Selective Catalytic Reduction)

32 Combustion Technology Type of Combustion technologies: Low-NOx Burners (LNB): Better air and fuel mixture Improves staged combustion process. Optimize air requirement during primary combustion of coal. Over Fire Air (OFA) / Seperated Over Fire Air (SOFA): Better air staging. Approx. 70% through LNB and 30% through OFA / SOFA. Expected reduction in NOx level < 20%.

33 Combustion Technology (Contd.) Typical Scheme of Windbox Arrangement for Low NOx

34 Challenges in Combustion Technology Challenges: Modification to existing windbox/ burner arrangement. Modification to the existing air duct / structure to accomodate SOFA arrangement. Shut down of approx. 6 to 14 weeks depending on extent of work involved. Impact on boiler efficiency.

35 Selective Non Catalytic Reduction (SNCR) Selective Non Catalytic Reduction: Introducing reagent at appropriate section of furnace where flue gas temperature is the range of 850 to C. Injection ports provided either by multiple injectors or by using retractable lances with multiple nozzles. Injection rate is controlled through each nozzle w.r.t boiler load to minimize reagent slip. Mixing of reagent either with water or compressed air. Expected reduction in NOx level < 50% max.

36 Selective Non Catalytic Reduction (Contd.) Typical Scheme of Selective Non-Catalytic Reduction

37 Challenges in SNCR Technology Challenges: Approx. 4 to 8 weeks of shut down. Ammonia slip to be kept minimum (less than 10 ppm). Ammonia storage and handling and space requirement. Provenness of OEMs in Indian context and for bigger units

38 Selective Catalytic Reduction (SCR) Selective Catalytic Reduction(SCR): Uses catalyst and hence installed at low temperature zone of furnace Temperature required is in the range of 250 to C. Located between economizer and air pre heater. Injection of Aqueous ammonia / Anhydrous ammonia / Urea into hot flue gas through injection grid. Mixture passes through a catalyst surface where the NOx is converted into nitrogen and water. NOx reduction efficiency shall be from 50% to 95%.

39 Selective Catalytic Reduction (SCR) (Contd.) Typical Scheme of Selective Catalytic Reduction System

40 Challenges in SCR Technology (Contd.) Challenges: Catalyst: Use of metals such as Molybdenum, Vanadium, Tungsten etc. in catalyst. Hence this is costly alternative. Catalyst designs for low ash coal used in countries abroad are well established. Use of these catalyst for high ash containing Indian coal are to be proven. Cyclone technology proposed by OEMs needs validation. Expected life of catalyst is max 3 years. Availability and regeneration facility of catalyst on long term after first instillation is concern. Disposal of catalyst is a challenge. Presently there is no guideline for disposal.

41 Challenges in SCR Technology (Contd.) Auxiliary Power: Introduction of catalyst increases pressure drop in fuel gas path. Increase ID fan loading and auxiliary power consumption of unit. In some cases replacement of ID fans may be required. Increase in auxiliary power shall be 0.5 to 0.7%. Layout Requirement: Space requirement to accommodate reactor in the existing layout. Modification in the existing duct. Support and strengthening of existing boiler structures. Non availability of data for existing plant for layout, foundation details etc. Effect on Performance: Ammonia bisulphate formation lead to air preheater fouling which may reduce the air preheater effectiveness.

42 Challenges in SCR Technology (Contd.) Cost and Schedule: Structural design cost due to catalyst weight and reactor span is considerable. The cost and schedule of implementation shall be reconfirmed. Provenness: Provenness of OEMs in Indian context.

43 Challenges in SCR Technology (Contd.) Challenges for use of reagents: Anhydrous Ammonia: Harmful for biological life and difficult to handle. Ammonia solution (19 to 25% in water): Handling cost due to dilution. Urea: Available in India is a challenge and needs to be imported. Requires elaborate heating arrangements for tank, pipe lines etc. for handling urea solution. Handling of Ammonia, Storage within existing layout needs detailed analysis

44 MessageBox(Arial, Fontsize18Bold) Estimated Capital Expenditure and Time Required Installation of pollution control equipment is expected to have an avg impact of paise per unit of electricity Pollutant Technology Analyst Cost Estimates (Rs lakh/mw) Impact on Levelised Tariff (Rs / unit) Construc tion Time (Months) Downt ime (Days) Additional Fixed Cost (e) (Rs./kWh) Particulate Matter ESP Upgradation yrs 0.45 SOx Emission NOx Emission Water FGD SCR/SNCR Cooling Tower (Cap Ex for Coastal Plants) Total Inland Plants Balance Life 10 yrs 15 yrs 25 yrs Coastal Plants Source: Ministry of Environment and Forests, CSE (Proceedings of Stakeholder Workshop, Sep 2016) 10

45 MessageBox(Arial, Fontsize18Bold) Impact on the O&M Costs* Parameter Plant A Plant B Annual OPEX Cost per unit Annual OPEX Cost per unit (Rs. Crs) (Rs./kWh) (Rs. Crs) (Rs./kWh) CT & CW System ESP FGD SCR / SNCR *at 85% PLF Typical Opex cost is expected between 25-33% (including Aux) to meet the new environmental norm. (Based on analyst reports) 11

46 Summary Technological & Implementation Challenges Total expenditure expected to implement environment norms will be over Rs 150,000 Cr. Fund Availability to fund capital expenditure at such a large scale is a issue In existing plants, it may not be possible to implement some of these new MoEF requirements like RCT System for coastal plants, SCR & FGD System in smaller old units Implementation of new Norms will have impact of CAPEX & OPEX on consumer tariff Ability of vendors to execute projects nationally at such a large scale may be a challenge Short timeframe (Only 1 year left) to implement norms is a major challenge Cost of equipments where demand could be more than supply and Indian manufacture content is yet to be ascertained. Challenges of outages timings and management of grid. Policy of incentive & penalty for complying & non complying Generator with option of phasing out non complying plant after pre-defined time frame need to be firmed-up

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