Desiccant Dryers

Desiccant Dryers are heat less air dryers that use a desiccant. They remove moisture from the compressed air to a dewpoint lower than 0°C. They usually comprise of two towers, each having the desiccant. The air is passed through one till the material is saturated and then diverted to the second tower. Single tower types have to be recharged time to time. Silica Gel, Alumino-Silicate Gel, Activated Alumina and Molecular Sieve are a few of the desiccants used in the system.

Heatless Desiccant Dryers use a small proportion of the processed compressed air to reactivate the wet desiccant bed.

These dryers use a small proportion of the processed compressed air to reactivate the wet desiccant bed. A heatless dryer will need between 15-18% of the dried air to be used for reactivation purposes. The principle it works on is it expands the compressed air to the normal atmospheric pressure thus reducing the relative humidity, initiating the recharge process of the desiccant. They can be pneumatically controlled and installed in hazardous locations.

Heat Reactivated Dryers work in the same way as the heatless dryers but are reactivated differently. They need a separate heat source to reactivate the desiccant bed where the moisture is released in the form of steam.