Desiccant

 

Desiccant type compressed air dryers are installed in applications where pressure dew points of -40°F or lower are needed. Continuous duty desiccant dryers use a regeration cycle to dry the "wet" off-line desiccant tower while an on-line tower dries the system air. Regeneration is available via the following methods:

 

Heatless

Heatless desiccant dryers are the least expensive to purchase, though often the most expensive to operate, with the regeneration purge air roughly 15% of rated flow. Controls are available to reduce the purge flow at partial loads, reducing energy costs.

 

Heated

External and internally heated dryers regenerate the desiccant using a small percentage of purge air. More expensive to purchase, they operate more efficiently than non-heated desiccant dryers.

 

Blower Purge

An external heater or heat source such as steam and a blower force hot air through the desiccant bed. The switching from one tower to the other is controlled by a PLC on either a fixed time or a demand basis.

 

Heat of Compression

These dryers utilize heat generated during compression by the air compressor to regenerate the desiccant beds. The Heat of Compression type dryer is on the of most energy efficient ways to dry compressed air.