What is absorption drying?

All atmospheric air contains a certain amount of water vapor. When air is compressed, the water concentration increases. To avoid future problems in the compressor installation, the compressed air must be treated in an desiccant dryer.

Absorption drying is a chemical process in which water vapor is bound to an absorption material. Absorption material can be either a solid or a liquid.

The general operating principle of adsorption dryer, also known as desiccant dryer, is simple: moist air flows over hygroscopic material (typical materials used are a silicate, or activated alumina) and is thereby dried.

Separation of water vapor from the moist compressed air into the hygroscopic material or “desiccant” causes the desiccant to gradually saturate with water.

Therefore, the desiccant must be regenerated regularly to regain its drying capacity.
Desiccant dryers are typically built with two drying containers for this purpose:
The first container dries the incoming compressed air while the second regenerates.