super critical power plant

super critical power plant is the power plant which operates at the

1. By sridurga 08761a0351 Super critical power plant

2. contents Introduction Critical condition Super critical parameters Necessity Comparison of sub critical and super critical plants Types of boilers Drum type boiler Once through boiler Advantages of once through Conclusion

3. What is super critical power plant??? The power plant which operates above the critical condition is a ”SUPER CRITICAL POWER PLANT”

4. Definition of critical Condition CRITICAL CONDITION IS THERMODYNAMIC EXPRESSION DESCRIBING THE STATE OF A SUBSTANCE BEYOND WHICH THERE IS NO CLEAR DISTINCTION BETWEEN THE LIQUID AND GASEOUS PHASE .

5. WHY ADVANCED SUPERCRITICAL? • Efficiency of the Rankine Cycle increases with increasing Turbine inlet Temperature and Pressure • Cycle efficiency of typical sub-critical plant is 38% whereas today’s supercritical technology increases this to around 45-47%

6. Sub-Critical vs Super Critical Description Sub Critical Super Critical Full Load Pressure <190 atm >240 atm Flow in Water wall 2-Phase 1-Phase Cycle efficiency Base + 2 - 3 % Approx Fuel saving Base +8 - 10 % Approx Boiler weight Base + 10 % Stages of reheat 1 2 Preferred

7. Types of boilers Drum type Once-through type

8. Design Types NATURAL STEAM DRUM FURNACE WALLS ECON. CONTROLLED TO SUPERHEATER CIRC. PUMP SEPARATOR CIRC. PUMP ECON. DISTRIB. HEADER ONCE THROUGH Natural circulation - well suited for < 175 kg/cm2 Controlled circulation - optimum solution for reliable high-pressure subcritical operation Once-through technology Suitable for sub and supercritical cycles

9. Super Critical Boilers Drum type boiler Natural Circulation Boiler Circulation through water walls by thermo-siphon effect Controlled Circulation Boiler At higher operating pressures (just below critical pressure levels), thermo-siphon effect supplemented by pumps to ensure safety of furnace wall tubes.

10. Super Critical Boilers Drum type boiler Steam generation essentially takes place in furnace water walls Fixed evaporation end point - the drum Steam -water separation takes place in the drum Separated water mixed with incoming feed water and fed back to water wall lower drum by means of boiler water circulating pumps (BWCPs).

11. Super Critical Boilers Once Through Boiler-Concept Once through system

12. Super Critical Boilers Once Through Boiler Once -through forced flow through all sections of boiler (economizer, water walls & super heater) Feed pump provides the driving head Suitable for sub critical & super critical pressures

13. Once-thru Boiler Major differences from Drum type boiler : Evaporator system Low load circulation system Separator

14. Once - thru Boiler Low load circulation system : The excess flow over the once-thru flow separated in separator . Recirculated back to the boiler directly by the dedicated circulating pump.

15. LOW LOAD SYSTEM WITH CIRCIRCULATION PUMP

16. Once -thru Boiler Separator : Separates steam and water during the circulating mode operation Runs dry in once through flow mode. Smaller in size compared to drum in a drum type boiler

17. Once -through Boiler Advantages :- Better suited for sliding pressure operation Steam temperature can be maintained over wider load range under sliding pressure Conservation of fuel resources. Shorter start up time Improvement in Efficiency

18. conclusion Super critical power plants are the efficient plants to produce greater out put although it has some drawbacks ….

19. Thank You