Question 255Steam Plants - 1st Asst/Chief70% to pass
While underway it is noticed that the main air ejector is having a hard time maintaining vacuum in the main condenser. When switching to the standby unit the vacuum returns to normal. Which of the following could be a possible cause?
AI Explanation
The correct answer is D) Clogged air ejector nozzle steam strainers.
The air ejector is responsible for maintaining vacuum in the main condenser by removing air and other non-condensable gases. If the air ejector nozzle steam strainers become clogged, it can restrict the flow of steam to the ejector, making it harder to maintain the necessary vacuum. When switching to the standby unit, the vacuum returns to normal, indicating the issue is likely with the primary air ejector system.
The other options are incorrect because excessive cooling water (A) and excessive feed water pump speed (C) would not cause the vacuum issues specifically in the main condenser. An open drain line from the after condenser (B) may affect the vacuum, but the prompt states the issue is noticed when switching to the standby unit, suggesting the problem is with the primary air ejector system.
Related Questions
#253 During maneuvering on a steam vessel, the condenser vacuum begins to decrease when the turbines are slowed for a slow ahead bell. Which of the following should be checked? #254 Scale in the air ejector first-stage nozzle could cause a decrease in the _______________.#256 Salt water contamination of condensate could occur at which component? #257 Which of the conditions listed could prevent a centrifugal condensate pump from developing its rated capacity? #258 Excessive condensate depression can result in _______________.