Why does the high-pressure heater constantly exhaust steam to the deaerator?

When the unit is restarted, a large amount of air is accumulated in the heater. By starting the exhaust gas, the gas can be discharged as soon as possible, thus ensuring that the heater can be well heated at the initial stage of operation and preventing the heater from leaking due to large thermal stress. Normal exhaust is to exhaust the non-condensable gas on the steam side of the heater to ensure the heat exchange efficiency.

The main function of deaerator is to remove oxygen and other non-condensable gases from boiler feed water to ensure the quality of feed water. If oxygen is dissolved in water, the metal in contact with water will be corroded. At the same time, if gas accumulates in the heat exchanger, the heat transfer resistance will increase and the heat transfer effect of the equipment will decrease. Therefore, any gas should not be dissolved in water, especially oxygen, which will directly threaten the safe operation of the equipment. Thermal oxygen removal is used in thermal power plants, and the deaerator itself is a mixed heater in the feed water regenerative system. At the same time, the high-pressure heater drainage, chemical make-up water, high-pressure drainage and exhaust steam with qualified water quality in all parts of the plant can be combined with deaerator for utilization to reduce the steam-water loss of the power plant. I. Working Principle of Headless Deaerator The main condensate (including make-up water) from the low-pressure heater enters the deaerator after being regulated by the inlet regulating valve, and is mixed with other hydrophobic water in the deaerator, and sprayed out through a nozzle or perforated pipe to form an umbrella-shaped water film, which is mixed with bottom-up heating steam for heat and mass transfer, so that the feed water can quickly reach the saturation temperature under the working pressure. At this time, most of the dissolved oxygen and other gases in the water are basically decomposed to achieve the purpose of oxygen removal.