Question 137Steam Plants - QMED

The correct answer is A) Intermediate pressure bleed steam. When a vessel is underway under full power, the boiler air heaters are typically heated by intermediate pressure bleed steam. This steam is extracted from the intermediate stage of the main steam turbine, providing a reliable and efficient source of heat for the air heaters. The intermediate pressure bleed steam is readily available and can be easily directed to the air heaters to preheat the combustion air, improving the overall efficiency of the boiler system. The other options are incorrect because they do not represent the normal source of heat for the boiler air heaters when the vessel is underway under full power. The main feed pump drive turbine exhaust (B) is not the primary source of heat, the dearating feed tank (C) does not directly provide heat to the air heaters, and the main boiler furnace (D) is not the normal source of heat for the air heaters.