Two schemes are proposed for the reduction in pressure of propylene gas at 430 K and 18 bar to 1.2 bar in a steady-flow process:

(a) Pass it through a throttle valve.

(b) Send it through an adiabatic expander of 72% efficiency.

For each proposal, determine the downstream temperature, and the rate of entropy generation in Jmol1 K1 . What is the power output for proposal (b) in kJmol1 ? Discuss the pros and cons of the two proposals. Do not assume ideal gases.