USCG Exam PracticeBoiler and steam propulsion fundamentals
What is the primary purpose of the deaerating feed tank in a steam propulsion plant?
- A. To raise feedwater to boiler operating pressure
- ✓ To heat feedwater and strip out dissolved oxygen and carbon dioxideCorrect
- C. To skim concentrated surface water and floating impurities from the boiler drum
- D. To condense exhaust steam back into water for reuse
Why B is correct
The deaerating feed tank heats the water and mechanically removes dissolved oxygen and carbon dioxide; any remaining oxygen is then scavenged chemically. Raising feedwater to boiler pressure is the function of the feed pumps; skimming surface impurities is the surface blowdown function; condensing exhaust steam is the condenser's role.