deaerering

Deaeration is a process that removes dissolved gases, especially oxygen and carbon dioxide, from liquids. It is employed to reduce corrosion, inhibit unwanted chemical reactions, and improve stability of products in industries such as power generation, chemical processing, beverage production, and pharmaceuticals.

Principle: The solubility of gases in liquids decreases with increasing temperature and decreasing partial pressure. In a deaerator, water is heated toward its boiling point and exposed to a low-pressure environment or to stripping gas so that dissolved gases are liberated and vented.

Common configurations: vacuum deaerators, steam jet or spray-type deaerators, and packed-bed or tray deaerators. In power plants, a deaerator typically uses live steam to heat feedwater and a vacuum or vented surface to carry away released gases; the output is feedwater with very low dissolved oxygen.

Operational considerations: proper control of temperature, pressure, and venting is essential. Oxygen scavengers or AVT strategies may be used in closed systems to further reduce dissolved oxygen. Measurements of dissolved oxygen are used to verify performance. Deaeration requires energy input for heating and, in some designs, steam consumption.

Applications: boiler feedwater treatment, process water in chemical and pharmaceutical industries, and beverage production to prevent oxidation or foaming. Limitations include incomplete removal, maintenance needs for tanks and vents, and the cost of steam or vacuum systems.