Problem 6.14:
A steam turbine generates 800 kW of work by expanding steam from 50 bar, 400 °C to 1 bar. At the exit of the turbine the steam contains 2% moisture.
a) Determine the flow rate of steam through the turbine.
b) Determine the efficiency.
c) Determine the rate of entropy generation in kJ/K s.
Problem 6.15:
Methane passes through a compressor and is subsequently cooled in a heat exchanger. Methane enters the compressor at 1 bar, 20 °C with volumetric flow rate 30 ft3/min; it exits the heat exchanger at 10 bar, 20 °C.
The compressor efficiency is 80%. Assuming methane to be in the ideal-gas state with
J/mol K, do the following:
a) Calculate the work in the compressor (in J/s)
b) Calculate the required heat in the heat exchanger.
c) Calculate the entropy generation.