Discuss the pros and cons of the two proposals.

Two schemes are proposed for the reduction in pressure of ethylene gas at 375 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 70% efficiency.

For each proposal, determine the downstream temperature, and the rate of entropy

generation in J⋅mol−1⋅K−1. What is the power output for proposal (b) in kJ⋅mol−1?

Discuss the pros and cons of the two proposals. Do not assume ideal gases.