USCG Exam PracticeBoiler and steam propulsion fundamentals
The economizer on a water-tube boiler serves which of the following functions?
- A. It raises the temperature of saturated steam above its boiling point before it enters the main engine
- B. It removes dissolved oxygen and carbon dioxide from the feedwater before it enters the boiler drum
- ✓ It preheats incoming feedwater by extracting heat from the flue gas passing through the uptakesCorrect
- D. It controls the concentration of dissolved solids by skimming surface water from the steam drum
Why C is correct
The economizer is a heat-recovery surface located in the flue gas path beyond the generating tubes. It preheats incoming feedwater using the residual heat of the combustion gases, improving overall boiler efficiency. Raising steam temperature above saturation is the function of the superheater; dissolved gas removal is performed in the deaerating feed tank. (NAVEDTRA 14104 §4-1)
Cited:NAVEDTRA 14104 §4-1