Water from an open deaerator feedwater heater flows to where?

The correct choice is that water from an open deaerator feedwater heater flows to the feedwater pump. A deaerator feedwater heater is designed to remove dissolved gases, particularly oxygen and carbon dioxide, from the feedwater before it enters the boiler. This process is critical because dissolved gases can lead to corrosion and other issues in the boiler system.

Once the feedwater has been adequately deaerated and heated, it is sent to the feedwater pump. The purpose of the feedwater pump is to pressurize the water so that it can be injected into the boiler at the required pressure. This ensures the efficient operation of the boiler, as the feedwater must enter the steam drum at an appropriate temperature and pressure for effective steam generation.

The other options, while related to boiler operations, do not accurately represent the flow path from the deaerator. The steam drum serves as a reservoir for steam and water but is not the direct endpoint of the feedwater from the deaerator. The blow-off valve is used to remove water and impurities from the boiler system, and the safety valve is a critical safety device designed to release excess pressure. Neither of these components is the next step for the feedwater post-deaeration.