Question 42 QMED01 - Junior Engineer

The Correct Answer is B. The **Main feed system** is the correct choice because its primary function is to deliver treated feedwater (which has been heated) under high pressure into the boiler drum. When a boiler is idle and its water level needs to be raised (or maintained), the main feed pump is the dedicated equipment responsible for pressurizing and injecting the necessary water volume directly into the boiler. **Why the other options are incorrect:** * **A) Auxiliary condensate system:** This system typically handles condensate returns from auxiliary steam consumers (like steam traps or smaller heat exchangers). Its flow capacity and pressure are generally too low for injecting large volumes of water directly into the high-pressure environment of a boiler drum. * **C) Condensate recirc system:** This system usually involves circulating condensate, often for cleaning or warming up specific parts of the steam/water circuit (like low-pressure heaters or the hotwell), but it is not the primary mechanism for pumping water directly into the boiler drum itself. * **D) Main condensate system:** The main condensate system collects condensate from the main condenser (after the turbine) and pumps it through low-pressure heaters toward the deaerator. While it handles the bulk of the water, it operates at relatively low pressure and is upstream of the deaerator and the boiler feed pumps; therefore, it cannot inject water directly into the boiler drum.