Deaerator is a device that eliminates non-condensable gases – oxygen and carbon dioxide dissolved in the feed water, to prevent corrosion of the feed water system in the System Power Equipment steam generation plants, the function of open type heat exchange for heating water, and continue Net Suction Head positive of the constant feed water pump.

A deaerator is a device that is widely used for the removal of oxygen and other dissolved gases from the feedwater to steam-generating boilers. – Wikipedia


Principle of Dearators

Dearator normally works based on the following principles.

Henrys Law

The solubility of the gas in a liquid is directly proportional to the partial pressure. Therefore if we decrease the partial pressure of the dissolved gas by adding steam in Deaerator, its solubility decreases and the gas is removed from water.

Inverse Solubility of Water

When the temperature of water is increased, the dissolved oxygen content in the water is decreases. Therefore the water temperature is increased by adding steam in Deaerator, the dissolved gas solubility is decreased and the gases are removed from water.

Read more – Importance of Deaerator Tanks

Deaerator consist of two drums where smaller drum is prelimenery heating and exhaust gases from feedwater, while the larger drum is a shelter for feedwater that falls from a smaller drum on it. On the smaller drum contained spray nozzle that serves to spray feedwater into fine droplets of water so the heating process and exhaust gases from feedwater can be performed perfectly.

The main element in determining the success of this process is physical contact between feedwater and the hot steam. Some things that must be considered in the deaerator process are:

  • The pressure in the deaerator
  • The water level in deaerator
  • The amount of condensate water flow
  • The amount of feedwater flow

If the deaerator can not work properly can adversely affect to the quality of feedwater, condensate system and also increase the use of higher chemical in the next process.

To achieve good efficiency of deaerator, there are few things to be noted as follow:

  1. Maintain temperature and pressure as high as possible in accordance with the design
  2. Make sure gases such as oxygen can be discharged out from deaerator.
  3. Perform inspection of the inside of the deaerator to ensure all components are not damaged.