USCG Exam PracticeThermodynamics and heat exchangers
In the Rankine cycle, which combination of changes will improve the thermal efficiency of a steam plant?
- A. Lowering boiler pressure and raising condenser pressure.
- ✓ Superheating the steam, raising boiler pressure, and lowering condenser pressure.Correct
- C. Saturating the steam at lower temperature and increasing condenser back-pressure.
- D. Reducing feedwater temperature and eliminating the regenerative feedwater heaters.
Why B is correct
DOE-HDBK-1012 §1-5 states that Rankine cycle efficiency is improved by superheating, raising boiler pressure, lowering condenser pressure (better vacuum), and regenerative feedwater heating. Options A, C, and D each reverse one or more of these improvements.
Cited:DOE-HDBK-1012 §1-5