Deaerator operating principle

Physical deaeration

The operating principle of Stork's spray-type deaerator is based on physical deaeration, which takes place in two steps:

  • Pre-deaeration, where water is sprayed into part of the steam's space
  • ​Final-deaeration in the water tank where steam is brought into close contact with the water to be deaerated. The pre-deaeration is achieved by Stork's spraying device. Under all kinds of operating conditions, the sprayer assures the heating up of the condensate to saturation temperature and provides for a very large area for mass transfer. As the solubility of oxygen in water at saturation conditions is practically zero, oxygen transfers from the water droplets to the surrounding steam. As the steam condenses on the water droplets, the concentration of oxygen in the direct vicinity of the sprayer is increased, making it possible to vent a small amount of steam with a relatively high oxygen concentration.

Final deaeration in the water tank is achieved by injecting steam into the water tank. Depending on the conditions, steam, pressurized hot water, or a steam/water mixture can be used for deaeration.

A properly designed steam device, taking into account the hydro-dynamics in the water tank, will result in good contact between water and steam, allowing the oxygen to move from the water to the steam in accordance with Henry’s law.

Deaerator operating principle

Deaerated water readily available at startup

Instead of heating up the entire water bulk in the vessel during initial filling, only a small volume of water in the vessel is heated up to operating temperature. Once this small volume is heated (and thus also deaerated) the deaerator can be filled to normal operating level. As this occurs, water which has already been deaerated will be routed through the boiler.

Starting up by heating up a small volume of water will not only result in the availability of deaerated water during start-up, but will also eliminate the chance of water hammer.

Stork's spray-type deaerator design provides available deaerated water during start-up. This heating process ensure safe and reliable operations