Example 4.16: Feasibility of Process
Looking for ways to improve energy utilization in a chemical plant, a young intern proposes to design a process that will use steam in a closed system to produce work. The steam is available at 10 bar, 650 °C, and will be delivered at 1 bar, 150 °C. The intern expects to generate 1200 kJ/kg from this process. A heat source is available at 200 °C, should the process need any heat.
Determine whether the company should go ahead with this plan.
Example 4.18: Irreversible Expansion in Vacuum
A closed insulated cylinder is divided into parts by a piston that is held into place by latches. One compartment is evacuated, the other contains steam at 7.5 bar, 300 °C. The latches are removed and the gas expands to fill the entire volume of the cylinder. When the system reaches equilibrium, its pressure is 1 bar. Determine the entropy generation.