Superheated steam at 600 C and 4000 kPa is fed into a turbo expander at a rate of 10 kg/s. The steam expands and leaves the expander at 500 kPa pressure and 300 C. It is known that there is a heat loss of 50 kJ/sec. This heat loss can be assumed to take place at a surface temp of 500 C.
a) Write down the appropriate forms of the energy balance and entropy balances for this case.
b) Calculate the work produced per second.
c) Is the expansion reversible? if not calculate the entropy generation per second.
d) If the expansion were reversible, and assuming the same rate of heat loss, what would be the exit temperature if the exit pressure is kept at 500 kPa