High Efficient Cogeneration in Seshasayee Paper -Erode

Transcription

1 High Efficient Cogeneration in Seshasayee Paper -Erode Dr T.G.Sundara Raman Seshasayee Paper and Boards Ltd. National Workshop for Promoting Industrial Energy Efficiency KEP/BEE New Delhi 8 th Nov. 2016

2 WHAT IS COGENERATION

3 Power Borrowed from Grid to Cogen Process CHP needs +Surplus Power for Export Grid Power Generation Net Power from TPS Net Power Avail at Plant Station Power Consumption T&D Losses Power for Export Net Power for Process Req. Power Generation in HP Cogen Cogen Co-Gen Plant HP Steam Generation Net Steam to Process ASC

4 SPECIFICATIONS OF THE 2 HP COGEN UNITS CPP Chemical Recovery Cogen Boiler #10 Parameter Boiler #11 AFBC Boiler Type Chemical Recovery Boiler 117 TPH ECR : 106 TPH Rated Steam Evaporation 95TPH(Phase1*) 140TPH(Phase2) 106 kg/cm² SOP 65 kg/cm² 510 C SOT 465 C 135 C Feed inlet temperature 135 C Imported coal Fuel Black 70% solids concn. 21 MW- DEC STG 16 MW- EBP 10.5/4.0 kg/cm² E1/E2 10.5/4.5 kg/cm² 0.09 ata Condensing MW(Phase1*) / 5

5 STEAM & POWER OPTIMISATION WITH 2 HP COGEN BATTERY ON LINE BLR#11 BLR#10 VHP HP 16 MW EBP 21 MW DEC E1 P2 E1 P1 E2 E2 LP LP MP

6 Atmospheric Fluidised Bed Combustion High Pressure Boiler [#10] [Babcock UK] -Original Design Bubbling Fluidised Bed Combustion Boiler with economizer & air-heater at back-end High pressure (106 ksc) unit 510ºC Steam Temperature No in-bed Superheater Rifle bore Studded Bed Coils Under-Bed Feeding 135ºC Feed water Temperature Rifle bore bed coil tube Enviro-Coal (Low S & Ash content) High Thermal Efficiency ( > 80 % )

7 INNOVATIVE PROJECT - 1 Conversion of Bubbling to Spouted AFBC HP Boiler with increased bed heating surface for enhanced High Pressure Steam & Power generation Date of Commencement : Date of Completion : Investment : Rs 10 Crores Monetary savings : Rs Crores BEFORE RETROFIT SINGLE HEADER SINGLE BED COIL DESIGN AFTER RETROFIT DOUBLE HEADER DOUBLE BED COIL DESIGN DECK PLATE / BOTTOM WATER WALL DECK PLATE Increasing bed coil heating surface accommodated within the existing furnace area, thereby increasing steam generation in HP Boiler 8

8 Imported Coal A.Proximate Analysis Constituent Unit As Fired Moisture % 20 Ash % 4.3 Volatile Matter % Fixed Carbon % GCV kcal/kg 5410 B. Elemental Analysis Carbon : 48.7 % Hydrogen : 5.3 % Nitrogen : 1.0 % Sulphur : 0.5 % Oxygen : 20.2 % Halogens : Traces Heavy Metals : BDL

9 High Combustion efficiency : >99% Design LOI [Design] : ~15% UBC Loss : 1.1 % Actual LOI : 9 to 10% UBC Loss : % CO in flue gas : Traces Combustion effy : > 99 % Action Initiated Stoppage of PA Fan Fuel Nozzles thoroughly cleaned during the last shut Bed material topped up with fresh material when required.

10 Steam Cost Reduction through Switch from Low to High Grade Coal in Upgraded Boiler # 10 Parameter Units Earlier Present Remarks Low GCV High GCV Switch to higher grade coal GCV ( arb) Kcal/kg As received basis TM % Total Moisture Landed Cost Rs/te Imported Coal Efficiency % Boiler thermal η Steam Evapn. t/t Fuel based Net Steam to fuel t/t Incl transf & carpet losses Spec Energy Consn redn. % Basis 4-5% Impact on PAT

11 Boiler 10 upgradation Impact on overall Operational Results & Analysis Increase in Steam generation : 80 to 105 TPH Increase in Power generation through 21MW STG : 13.5 to 19 MW Station Power consumption reduction : 7000 units/day Power Export : 3 to 4 MW (Commencement from Nov 2015) Grid Power Import drastically reduced Additional LP Steam for Process : Ensured 12

12 INNOVATIVE PROJECT - 2 Coal fired Boiler 10 - Station Power consumption reduction by integrating Energy Efficient Boiler feed Pump with Low Differential Pressure Control Valve. Date of Commencement : Aug 2015 Date of Completion : Oct 2015 Investment : Rs 2 Lakhs Monetary savings : Rs 32 Lakhs Prelude : High pressure drop across the control valve of Boiler Feed pump had triggered the design of a control valve with lower differential Pressure so as to retain the existing energy efficient Boiler feed pump. Benefits achieved : Station power consumption reduction : 5000 KWh /day Net power available for export : 0.2 MW Annual GHGE reduction : 2000 tco 2 e ( ) Why it is innovative: Energy efficient Boiler Feed Pump integrated with specially designed control valve with lower differential pressure to effect station power consumption reduction - first of its kind in Manufacturing Industry. Replication potential: Can be replicated by all industries for their 13 boiler feed pumps.

13 BFP Efficiency [%] Advanced Energy Conservation Scheme BFP for H.P. Steam Generator [Boiler 10] DP across BFP CV [bar] Efficiency [%] of BFP in Operation DP across EFBFP Control valves Boiler 10 LargeBFP EFBFP CV original CV LowDP Feed Water Flow to Boiler 10 [ TPH] Feed Water Flow to Boiler 10 [ TPH] Energy Saving : 4500 units/day Energy Saving : 1000 units/day

14 Innovative Project Power Management Boiler Feed Pump Energy Efficient BFP with Low DP Control Valve to suit Boiler Steam Rate TPH Efficiency % Power Consumption Power Savings % Daily Power Savings in Units Standby BFP Basis Basis EE BFP + Low DP CV

15 CPU+ HRU - INTEGRATED WATER & ENERGY MANAGEMENT -BOILERS. Process Condensate : 90 C to 40 C DM Water Preheating : from 32 C Heat Recovery : 4 MWt Process condensate polishing Waste heat recovery through PHE Condensate polishing resin bed FWT To Deaerators Hot Fluid Filter PHEs ACF MB Polished Condensate Process Hot / Condensate Tank ST

16 Impact on Enhanced performance of DEC STG Boiler #10 upgradation Higher Cycle efficiency of STG relating to increased Power generation Increased Condensing loading resulting in lowered Specific Steam Consumption Marginal increase in Generator efficiency due to increase in Power Generation Maintaining rated Main steam temperature of ~ 505 C 18

17 CPP- Power Generation Enhancement Increase in Gross Cycle efficiency Successful Implementation of Innovative schemes, had resulted in : Net Power generation enhancement -through: 1. Minimize Exhaust steam Dryness Fraction 2. Maximize Condenser Vacuum 3. Generator efficiency enhancement 4. Minimizing/Non-operation of inefficient MP Boiler(s) 5. Reduction in Station Power Consumption through High Energy Efficiency BFP with low DP Control Valve in place

18 High Generator Efficiency 21 MW, 16 MW Steam Turbo-Generators 21 MW 16 MW Type Double Extraction cum Condensing Extraction cum Back Pressure Design 97.6 % 97.7 % Actual 97.9 % 98.1 % [Industry Record] Gain 0.07 MW 0.06 MW 23

19 SPC [%] Cogen Station Power Consumption[%]

20 INNOVATIVE PROJECT - 3 DM water switch related to heat recovery from Turbo-generator winding heat dissipation for increased Cycle efficiency Date of Commencement : Jan 2016 Demonstration done : Aug 2016 Investment : Re 1 Lakh Monetary savings :Rs 20 Lakhs Proposal : DM water instead of cooling tower water is supplied to generator air cooler and is returned to the De-aerator at a higher temperature thereby reducing LP steam. G EXISTING G MODIFIED STEAM TURBINE STEAM TURBINE COOLING TOWER WATER IN COOLING TOWER WATER OUT DM WATER IN DM WATER OUT GENERATOR AIR COOLER GENERATOR AIR COOLER 25

21 INNOVATIVE PROJECT - 3 BACKGROUND : Energy wasted through the cooling tower and the fouling of generator tubes triggered the scheme development. BENEFITS ESTIMATED: De-aerator LP steam consumption reduction by 12 TPD Annual GHG emission reduction 1100 tco2e Fouling of generator air cooler tubes is avoided Enhanced winding temperature reduction. REPLICATION POTENTIAL : Steam turbines with condensing units related to Cogeneration can take advantage of the scheme through implementation. Concept can be suitably modified for Thermal Power plants by utilizing turbine condensate instead of DM water. 26

22 . RECOVERY COGEN ENERGY DISTRIBUTION Fuel- Input Energy Boiler BFP MSL APH APH PRDS Deaerator EBP Turbine P Recausticizing Evaporator MP Steam for Process LP Steam for Process Fuel Heating

23 Innovation related to Low Carbon Economy Maximizing Green Power generation in Recovery Cogen through: Minimal/No extraction & maximizing Exhaust LP flow in 16 MW STG Maximizing steam inlet temperature through operating the Recovery Boiler at high SOT & effecting reduction in steam temperature loss through highly effective advanced state of the art insulation of Main steam pipe-line

24 16 MW STG : Energy Management Maximizing E2 steam with E1 minimal Power gen. increase. : 0.4 MW Addl. power gen. through increase in flow of E2... : 0.05 MW Addl Green power gen. : 0.45 MW REC : 300 units/month GHGE reduction : 1800 tco2/yr

25 Waste to Power Advanced Boiler Main steam pipeline reinsulation- online Replacement of existing insulation with fresh insulation mattress of higher thickness [210mm]& density [140kg/m3] ; Advanced cladding pin design Steam temperature drop redn. from 10/12 C to 5/6 C. Radn & convecn heat loss redn. Enthalpy gain in 16MW STG: 3kcal/kg Addl. Power genern : 0.3 MW GHGE Reduction : 2400 tco2/ yr

26 Recovery HP Cogen : Energy Management Increased Feed water inlet temperature to Boiler :Case Study Increased Feed Water inlet temperature from 136 to 141 C to Economiser Power gen. increase. : 0.06 MW Green Power enhancement:0.5 MU/yr REC : 40 units/month GHGE reduction : 250 t CO2e / yr 31

27 Conclusions Energy Efficiency Gains through Modified Boiler Design Quantum increase in HP Boiler Steam generation at rated steam temperature Overall Heat rate of Boiler House [CPP] efficiency enhancement with high steam economy-steam loading reduced on inefficient MP Boilers Consequent increase in turbine steam loading had resulted in high cycle efficiency Surplus Power available for Grid Export [ ~3MW ] Availability of Boiler 10 with 21 MW STG : high at >98% GHG Emission reduction of over tco 2 /annum

28 Leveraging Aux. Steam Consumption Process condensate polishing with HRU Higher feed water temperature Reduced DM water consumption and lowered Deaerator steam consumption Increase in Steam economy High Feed water quality Low Blow-down ; Pressure part healthiness Combustion intake air reducting planned LP steam consumption lowered

29 LEVEREGING ELECTRICAL POWER IN HP COGEN Set Steam Inlet Temperature to Turbine at Design Maximum Low Enthalpy Drop through economic sizing and heavy insulation of main steam line High Energy Efficient Boiler Feed Pumps integrated with Low DP Control Valves Increase in Steam Generation with Boiler Water Temp. at 141 C (instead of 105 C) High Efficiency Turbine (With lower exhaust steam dryness) for DEC Steam Turbine Identifying & Changing from MP to LP Steam (Steam Switch) for Process needs 5 to 10 kwh/t 5 to 10 kwh/t 7000 units/day +30 kwh/t 30 to 50 kwh/t To Suit

30 Cleaner Environment Facets Low S ( < 0.4 %)in coal SOx emission low Low Ash ( 3 to 4 %) in coal High efficiency 3 field ESP Imported coal with high GCV GHG Annual Emission Reduction Bottom/Fly-ash handling minimal Low SPM & RPM in stack gas < 30 mg/nm³ Particulates, SO2 & NOX quantity discharged : Low tco2e

31 For further enquiry please contact: Dr T.G.Sundara Raman Mob. No,: drram@spbltd.com Thank You 36