Consider a steam power plant using a reheat cycle as shown. Steam leaves the boiler and enters the turbine at 4 MPa,350 C (h3=3095 kJ/kg). After expansion in the turbine to 400 kPa (h4=2609 kJ/kg), the steam is reheated to 350 C (h5=3170 kJ/kg) and then expanded in a low-pressure turbine to 10 kPa (h6=2165 kJ/kg).
The thermal efficiency of the plant neglecting pump work is _____ A. 15.8% B. 41.1% C. 48.5% D. 58.6%
The enthalpy at the pump discharge (h2) is __________
A. 0.33 kJ/kg B. 3.33 kJ/kg C. 4.0 kJ/kg D. 33.3 kJ/kg
Answer: From the figure, the enthalpy at each stage has been given readily. But in real-life problems, we have to find out these values from steam tables. Also, pump work is neglected in this case but that may not be the case always.
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