Question 434Steam Plants - Assistant Engineer

The correct answer is D) Marine growth on the cooling water side of the main condenser. Marine growth on the cooling water side of the main condenser can prevent the vacuum from reaching the desired level. This is because the marine growth reduces the efficiency of the heat transfer process, which is essential for creating the necessary vacuum in the condenser. The reduced heat transfer leads to a higher backpressure in the condenser, making it more difficult to achieve the desired vacuum level. The other options are not directly related to the vacuum level in the condenser. Option A, condensate recirculating back to the condenser during maneuvering, would not prevent the vacuum from reaching the desired level. Option B, maintaining steam pressure to air ejectors at 10 psig above the designed supply pressure, is also not a factor in the vacuum level. Option C, steam leaking from the turbine glands, would not directly impact the vacuum level in the condenser.