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 the open type heat exchanger 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 Deaerators

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 the water.

Inverse Solubility of Water

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

Read more – Importance of Deaerator Tanks

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

The main element in determining the success of this process is physical contact between feed water 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 cannot work properly can adversely affect the quality of boiler feed water, condensate system and also increase the use of the 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.