Deaerator
A deaerator removes dissolved oxygen and carbon dioxide from boiler feedwater by heating it close to saturation and stripping the gases with steam. Removing oxygen protects boilers and pipework from corrosion.
Dissolved oxygen in feedwater is the main driver of pitting corrosion in boilers and condensate lines. A deaerator sprays incoming water into a steam atmosphere, raising it to near boiling point where gas solubility falls to almost nothing; the liberated gases are vented to atmosphere. The deaerated water collected in the storage section is also preheated, improving boiler efficiency, and a residual oxygen scavenger chemical is usually added downstream as a safeguard.