Consider a Rankine cycle with reheat. Compressed water enters the boiler at 21 bars and is heated to 500C. Due to frictional effects there is a pressure loss of 1 bar in the boiler. At the exit of the boiler 40% of the steam produced is extracted for an external chemical process. The exhaust pressure of the first turbine is 5.0 bars. The steam is then reheated to 440C. The condenser operates at one bar. Make-up is added at the condenser. Determine:
(a) thermal efficiency of the cycle
(b) second law effectiveness
...ical Work generation ).
The remaining 60% is used for driving an steam turbine, with an exhaust of 5 bara. I assume that steam is at saturation temperature.
State 4 : Saturated steam at 5 bara and 151.8 degrees C ; h4 = 640 KJ/Kg s4 = 1.86 KJ /(Kg * K ).
Steam is overheated to 440 degrees C and 5 bara. This state is 5 and conditions are h5 = 3356 KJ/Kg and s5 = 7.91 KJ/(Kg*K).
Finally, the steam enters another turbine, where is exhausted to 1 bar and, I supposed to saturation ( 99.6 degrees C).
State 6 : subcooled water ; h6 = 2674 KJ/Kg s6 = 7.36 KJ/(Kg * K)
Steam is condensated to 25 degrees C and 1 bara h7 = 104 KJ/Kg s7 = 0.37 KJ/(Kg*K).
Assuming a base of 100 Kg/h of ...