Prof. D.N. Reddy Director Centre for Energy Technology University College of Engineering

1. STEAM POWER CYCLE OPTIMISATION Prof. D.N. Reddy Director Centre for Energy Technology University College of Engineering Osmania University.

2. Thermal performance • The main impact of the Supercritical Cycle is to increase the overall plant efficiency by reducing Fuel consumption for Unit of Power Generated.

3. Reduction in CO2 emissions to the extent of 15% sub-critical = 38% supercritical = 45% at 600 oC Temp 650 – 700oC  = 50 – 55%

4. Steam Cycle performance • 1969 - 36% • 1985 - 40% • 1990 - 43-44% • 2000 Double Re-heat - 45-46%

5. Improvement in Efficiency • Increase in Main Steam Pressure and Re-heat Steam Temp • Final Feed Water Temperature ( Depends on: Increase in No.of Re-heat stages and Number of Feed Water Heaters)

6. BOILER EXIT GAS TEMPERATURE ( 20oC reduction increases Efficiency by 1.1%) • Condensor pressure • Reduction of Auxillary Power Consumption • Improvement in Component Efficiencies

7. Part Load Efficiency Part loadReduction onEfficiency • Sub-critical 75% - 4% 50% - 10-11% • Super-critical 75% - 2% 50% - 5.5 –8%

8. Boiler Design Optimisation • Sub-Critical Boilers - Drum Boilers Steam and Water Separated in the evaporator • Super-Critical - Once-through design

9. Two pass and Tower Design Combustion Zone - Spirally Wound Membrane / inclined tubing preferable Increase in Pressure - Thicker sections / Higher and Temp grade composition

10. Current state of Art Boiler out let Steam Pressure and Temperature = 300 bar/580-600 oC Limitations • Boiler Furnace Wall • Complex Welding

11. Vertical Furnace Tube Design • Cheaper and less Complex Furnace Design • Easier Furnace Framing • Lower Pressure Drop (higher efficiency)

12. Current status of Turbine Design Shaft Speeds - 3000-3600 rpm Inlet Steam conditions - 240 bar/565oC 300 bar/600oC Output = 1100 MW

13. Feed Water Pumps Boiler Feed Water Pumps - 3-4% of gross power output Feed Water Temperature - 280 – 300oC Flue Gas Temperature - 120oC (can be reduced to 80oC using Heat Recovery System) Upstream Flue gas De-Sulfurization

14. Improvement in Efficiency Heat Recovery System = 0.6% Coal Fired = 1.0% Lignite Fire

15. Turbine and Cycle Optimisation • Improved blading profiles making use of Modern CFD Technologies • Higher Final Feed Temperature and Bled Steam Temperature • Bled Steam Tapping off the HP cylinder

16. Improved Efficiency of Auxillaries • Lower condenser pressures using larger condensers and large exhaust areas • Large unit sizes improving Turbine Efficiencies • Increasing automation and level of controls • Optimising plant layout

17. Alternate Boiler Technologies • Gasification Cycles • FBC’s AFBC PFBC CFBC • HRSG to Power a Turbogenerator

18. Schematic Diagram of a Steam Power Plant

19. Process Plant Diagram

20. Steam Turbine Cycle

21. The Ideal Reheat Cycle

22. The Ideal Regenerative Cycle

23. Regenerative Cycle with Open Feed Water Heater

24. Closed Feed Water Heater

26. Effect of Boiler Pressure on Rankine-Cycle Efficiency

28. Pressure of Turbine Inlet

30. THANK 'U'