Question 23 QMED04 - Boiler Technician-Watertender

The Correct Answer is D **Why option D ("air ejector condenser") is correct:** In a main propulsion steam turbine installation, the primary function of the condensate pump is to remove water (condensate) from the main condenser hotwell. The condensate, now under pressure, must first pass through the **air ejector condenser (AEC)**. The steam used to operate the air ejectors (which maintain the high vacuum in the main condenser) contains heat and is mixed with non-condensable gases. Passing the main condensate through the tubes of the AEC serves two crucial functions: 1. **Condensing the Air Ejector Steam:** The relatively cool condensate provides the necessary cooling surface to condense the motive steam used by the air ejectors, recovering this valuable pure water back into the feed cycle. 2. **Pre-heating the Condensate:** As the AEC steam condenses on the shell side, its latent heat is transferred to the main condensate flowing through the tubes, providing the first stage of heating (pre-heating) in the feedwater cycle. **Why the other options are incorrect:** * **A) deaerating feed tank (DFT):** The DFT is a crucial component for removing dissolved gases, but it operates at a higher temperature and pressure than the AEC. The condensate typically passes through several heaters (including the AEC and usually a low-pressure heater) before being pumped by the feed booster pump (or main feed pump, depending on design) into the DFT. It is not the *initial* destination after the condensate pump. * **B) first stage heater:** While the AEC is technically the very first stage of heating, the term "first stage heater" usually refers to a dedicated low-pressure shell-and-tube heat exchanger *after* the AEC. The condensate must pass through the AEC first to recover the air ejector steam. * **C) distillate tank:** The distillate tank is used to store makeup feed water (freshly produced water) before it is introduced into the cycle, often downstream of the condenser. The condensate pump discharges water that is already *in* the main cycle, not into the storage tank for makeup water.