Thermal deaerators are commonly used to remove dissolved gases infeedwaterfor steam-generatingboilers. Dissolvedoxygenin feedwater will cause serious corrosion damage in a boiler by attaching to the walls of metal piping and other equipment and formingoxides(like rust). Dissolvedcarbon dioxidecombines with water to formcarbonic acidthat may cause further corrosion. Most deaerators are designed to remove oxygen down to levels of 7ppbby weight or less, as well as essentially eliminating carbon dioxide.^[16][17]The deaerators in the steam generating systems of mostthermal power plantsuse low pressure steam obtained from an extraction point in theirsteam turbinesystem. However, the steam generators in many large industrial facilities such aspetroleum refineriesmay use whatever low-pressure steam is available.

There are many different deaerators available from a number of manufacturers, and the actual construction details will vary from one manufacturer to another.

Deaerators are also used to remove dissolved gases from products such as food, personal care products, cosmetic products, chemicals, and pharmaceuticals to increase the dosing accuracy in thefilling process, to increase product shelf stability, to prevent oxidative effects (e.g. discolouration, changes of smell or taste, rancidity), to alterpH, and to reduce packaging volume. Vacuum deaerators are also used in the petrochemical field.^[19]