Industrial compressed air dryers: working principle, types, and selection

Compressed air dryers work by reducing the dew point of the air, which prevents condensation from forming. There are several different working principles depending on the type of dryer, each suited for specific applications and requirements.

• Air Dryer Working Principle: The general working principle involves cooling the air to condense moisture or using desiccants to absorb moisture from the air.

• Heatless Air Dryer Working Principle: Involves using desiccants without heat to remove moisture from the air stream.

There are several types of compressed air dryers, each with unique features and applications:

Refrigerated air dryers are the most commonly used type of air dryers. They work by cooling the compressed air to remove moisture. This type of dryer is suitable for general industrial applications where dew point suppression is sufficient.

Working Principle: The air is cooled to about 3°C (37°F), causing the moisture to condense and be separated from the air stream. The dry air is then reheated before it is delivered to the point of use.

Working Principle: Compressed air passes through a chamber filled with desiccant material, which adsorbs the moisture. The desiccant is regenerated by heating or using purge air.

Rotary drum air dryers are highly efficient and energy-saving dryers. They are ideal for industries that require a consistent dew point without using any purge air.

Working Principle: The air passes through a rotating drum that has an internal desiccant wheel. The drum continuously rotates, allowing the desiccant to absorb moisture and regenerate simultaneously.

Membrane air dryers are suitable for point-of-use applications and environments requiring compact, low-maintenance solutions. They use a selective permeation process to remove water vapor from compressed air.

Working Principle: Compressed air passes through a bundle of membrane fibers, where water vapor diffuses through the membrane while the dry air continues to the point of use.