A steam power plant operates on a regenerative Rankine cycle and produces a net power output of 150 MW. Steam enters the turbine at 10 MPa (h = 3375.1 kJ/kg) and enters the condenser at 10 kPa (hs = 2654.1 kJ/kg). The turbine has an isentropic efficiency of 80%, and the pump operates at 95% efficiency. Steam is extracted from the turbine at 0.5 MPa (hs = 2089.7 kJ/kg) to heat the feedwater in an open feedwater heater. Water leaves the feedwater heater as a saturated liquid. Given these conditions, what is the fraction of steam extracted from the turbine?
State of water:
h (kJ/kg) water hf hfg
10 kPa 191.81 2392.8
500 kPa 640.09 2108.5
s (kJ/kg-K) v (m3/kg)
Sf 0.6492 1.8606
Sfg 7.5010 4.9606
Vf Vg 0.001010 14.674 0.001093 0.3749
Boiler
Open FWH
Condenser
Pump II
Pump I
