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Thermal power plant efficiency
The document discusses the efficiency and heat rate of thermal power stations, detailing the components of thermal power cycles, including boiler and turbine efficiencies. Various losses affecting efficiency, such as moisture in fuel and air, are analyzed, along with methods to optimize performance and reduce heat rates. Additionally, a financial perspective is provided, showing potential cost savings from reducing heat rates in coal usage.
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Thermal power plant efficiency
- 1. Thermal Power Stations Efficiency& Heat Rate 1 Manohar Tatwawadi 3/2/2021
- 2. Thermal Power CycleSchemetic S T A C K DRUM FURNACE SH RH ECON A P H A P H PA FANS FD FANS ID FANS HOT PA HEADER COLD PA HEADER BUNKER, RCF & CM ESP ESP HP HEATERS LP HEATERS, EJECTOR, GS COOLER CON HP IP LP GEN DEAIRATOR FEED TANK Boiler Feed Pumps CEP 210 MW P-130, T- 540 P-28, T- 320 P-24, T- 535 P-1.32, T- 180 P-0.0889, T- 43 P-0.0889, T- 43 P-22, T- 43 CW in, T- 30 CW out, T- 41 T- 156 T- 167 P-150 T- 173 T- 255 T- 340 P-145 T- 340 2 Manohar Tatwawadi 3/2/2021
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- 5. Efficiency Efficiency = Output/ Input Output = Input - Losses (Input - Losses) Input Efficiency = Efficiency = (100 - Losses) 100 5 Manohar Tatwawadi 3/2/2021
- 6. Losses in Boiler& Efficiency (As per Designer) Heat Supplied to Turbine (Output) Heat Lost in hot flue gasses = 6% Other Losses 1 Moisture in Fuel 1.2%. 2 Moisture in Air 0.1% 3 Hydrogen in Fuel 5.00% 4 Radiation Loss 0.2%. Heat Lost in Unburnt in Fly and Bottom Ash = 0.4% Total Heat Input = 100% C H I M N E Y E.S.P. F U R N A C E AirHeater IDFan Boiler Efficiency = 86.5% Excess Air Loss = 0.75% 6 Manohar Tatwawadi 3/2/2021
- 7. HP Turbine Efficiency InletSteam 130kg/sq.cm. 5350C Outlet Steam 30kg/sq.cm. 2800C HP Turbine Efficiency = 81.11% 7 Manohar Tatwawadi 3/2/2021
- 8. IP Turbine Efficiency InletSteam 27kg/sq.cm. 5350C Outlet Steam 1.2kg/sq.cm. 2000C IP Turbine Efficiency = 89.83% 8 Manohar Tatwawadi 3/2/2021
- 9. LP Turbine Efficiency InletSteam from IPT 0.09 kg/sq.cm. abs 470C Outlet Steam to condenser 1.2kg/sq.cm. 2000C LP Turbine Efficiency = 85% 9 Manohar Tatwawadi 3/2/2021
- 10. HP Turbine Efficiency= 81.11% IP Turbine Efficiency = 89.83 % LP Turbine Efficiency =85.00 % Turbine Efficiencies (Design Efficiencies) 10 Manohar Tatwawadi 3/2/2021
- 11. Turbine Losses Internal Losses 1.Nozzle Friction 2. Blade Friction 3. Disc Friction 4. Diaphragm gland and Blade tip leakage 5. Partial Admission 6. Wetness at Exhaust 11 Manohar Tatwawadi 3/2/2021
- 12. Turbine Losses contd… ExternalLosses 1. Shaft Gland leakages 12 Manohar Tatwawadi 3/2/2021
- 13. Cylinder Efficiency Causes ofdeterioration 1. Damage to blades caused by debris getting past the strainers 2. Damage to tip seals and inter-stage glands. 3. Deposition on blades (Last few IP Stages & first few LP Stages. 13 Manohar Tatwawadi 3/2/2021
- 14. Generator Losses & Efficiency 1.Copper Losses (I2R) 2. Iron Losses 3. Other Losses All the above losses account to 2% Hence the Generator Efficiency = 98% 14 Manohar Tatwawadi 3/2/2021
- 15. Steam Cycle Efficiency Water Steam Turbine HeatEnergy Energy Converted to Electrical Energy = 40% 100% Cycle Efficiency = 40% Heat Taken away in Condenser = 60% 15 Manohar Tatwawadi 3/2/2021
- 16. HEAT RATE One Unit1 KWH = 860 Kcal heat Heat required to generate 1 KWH is the heat rate Unit of Heat Rate is KCAL / KWH 16 Manohar Tatwawadi 3/2/2021
- 17. Energy generated bythe generator and losses Energy generated 1KWH (860KCAL) Energy going out of generator in the form of heat 20 KCAL Generator Energy given to the generator 880 KCAL 17 Manohar Tatwawadi 3/2/2021
- 18. TURBINE HEAT RATE& LOSSES Energy given to the generator 880 KCAL Heat going out from condenser CW System 962 KCAL Energy supplied by the boiler = Turbine Heat Rate (2065 KCAL) Other Losses in Turbine & Heaters 223 KCAL Condenser L.P.T To CEP 18 Manohar Tatwawadi 3/2/2021
- 19. Heat Lossesin theBoiler & Unit Heat Rate (As per Manufacturer) Heat Supplied to Turbine 2065 Kcal Heat Lost to Flue gas 122 Kcal Other Losses 1 Moisture in Coal 30 Kcal 2 Hydrogen in Coal 150 Kcal 3 Radiation Losses 5 Kcal. Heat in BA & FA Unburnt Coal 24 Kcal Total Heat Supplied to Unit 2396 Kcal C H I M N E Y E.S.P. F U R N A C E AirHeater IDFan 19 Manohar Tatwawadi 3/2/2021
- 20. GROSS UNIT HEATRATE 1. Gross Turbine Heat Rate = 2065 Kcal/KWh 2. Heat Losses in Boiler = 331 Kcal 3. Gross Unit Heat Rate = 2396 Kcal/Kwh (GUHR) 4. Heat Value of Coal (GCV)= 3500 Kcal/Kg 5. Coal required for Generation of 1 KWh =2396/3500 = 0.68 Kg. Reducing the HEAT RATE will reduce the consumption of Coal and SAVE COAL. 20 Manohar Tatwawadi 3/2/2021
- 21. HEAT RATE of210 MW UNIT S T A C K DRUM FURNACE SH RH ECON A P H A P H PA FANS FD FANS ID FANS HOT PA HEADER COLD PA HEADER BUNKER, RCF & CM ESP ESP HP HEATERS LP HEATERS, EJECTOR, GS COOLER CONDE NSER HP IP LP GEN DEAIRATOR FEED TANK Boiler Feed Pumps CEP HOT PRIMARY AIR HOT SECONDARY AIR 860 ¹ˆ Å . ˆ Á Å . /1 ¹ˆ Å̈ ¸Á ‚ (¡¸º ¹›¸’ ) Stn. Aux- 51 Kcal ¸›¸ú °¸¸÷ ¸ú ¥¸¸›¸ú- 20 ˆ Å ú . ˆ Á Å 880¹ˆÅ . ˆÁ Å . Heat Rejected 962 Kcal Total Turbine Losses includes Heat Rejected - 1185 Kcal Energy Input to Turbine 2065 Kcal Stack Loss 122 Kcal Unburnt-24 Kcal H2 fuel-150 Kcal H2O fuel-30Kcal Radiation- 5Kcal Total -210 Kcal Total Boiler Losses - 331 Kcal Total Boiler Input - 2396 Kcal Design Turbine Heat Rate - GTHR - 2065 Kcal/Kwh and Gross Unit Heat Rate- GUHR - 2396 Kcal/Kwh * Any amount of energy or heat/Coal/Water going out of cycle is increasing the heat rate. 21 Manohar Tatwawadi 3/2/2021
- 22. BOILER OPTIMISATION Boiler EfficiencyOptimisation A. Optimising of Total Air supplies Too Little air will cause Unburnt Losses and too much air will increase the dry flue gas losses. Carbon monoxide monitor can be effectively used for enabling supply of correct quantity of air for combustion (Residual CO Typical 100 PPM) 22 Manohar Tatwawadi 3/2/2021
- 23. BOILER OPTIMISATION Boiler EfficiencyOptimisation B. Unburnt in BA & FA Normally 4.8% in BA and 0.8% in FA •Measure of effectiveness of Combustion Process and Milling plant •Proper Adjustment of Supply of Secondary air •Furnace leakages 23 Manohar Tatwawadi 3/2/2021
- 24. BOILER OPTIMISATION C. AirHeater gas outlet temperature Causes for high APH gas outlet Temp 1. Ineffective APH Soot blowers 2. Holed & Torn elements generally at the cold end. 3. Deposits on Water tubes, Superheater 7 reheater Boiler Efficiency Optimisation 24 Manohar Tatwawadi 3/2/2021
- 25. BOILER OPTIMISATION Other Causesfor high APH gas outlet Temp High Excess air--- if very high will decrease the FG Temp Low FW Temp at Eco Inlet Defective Baffles in FG Path Poor milling & Poor combustion resulting in long burnoff time resulting in fouling as well. Use of High row of burners at low loads Air leakages before combustion chamber 25 Manohar Tatwawadi 3/2/2021
- 26. UNIT OPTIMISATION Monitor followingparameters for taking necessary steps for Unit Optimisation 1. Condenser Vacuum 2. Main Steam Press and Temp at Turbine Inlet 3. Reheat Temp at Turbine Inlet 4. Feed water temp at Eco Inlet 5. Boiler Excess air 6. Unburnt in Ash 7. APH gas outlet temp 8. Make up water consumption 26 Manohar Tatwawadi 3/2/2021
- 27. SAVING OF HEATIS SAVING OF COAL AND SAVING OF MONEY Cost of Coal = Rs 1800/- Ton = Rs 1.80 /Kg Heat in 1 Kg of coal = 3500 Kcal (Minimum) If the Heat Rate is reduced by 50 Kcal the value of 50 Kcal = 2.5 Paise/Unit (KWh Units generated by a 210 MW Unit in one day = 5040000 KWh Hence saving per day = 5040000X2.5 Paise = Rs 1,26,000/- Per day per unit 27 Manohar Tatwawadi 3/2/2021
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