1007. What is the source of heat for a second stage feed heater (deaerating feed tank) while a vessel is underway under full load?

Auxiliary exhaust steam heats the deaerating feed tank, providing a low-pressure steam source for feedwater heating and deaeration during full load operation. High, intermediate, and low-pressure bleed steam are typically used in closed feedwater heaters, while auxiliary exhaust steam recovers otherwise wasted energy.