Heated Desiccant Regenerative Air Dryer

Heat reactivated regenerative desiccant dryers may have internal or external heat applied by heaters.

There are several different types of heat reactivated regenerative dryers and below we discuss each type along with its advantages and disadvantages.  In all heated type regenerative dryers, the heat source can be provided by either electric or steam with the most common being electric.

Advantages of Internally Heated Regenerative Desiccant Dryers include:

Low dew points can be achieved without potential freeze-up.

Activated Alumina desiccant

No purge air required

All compressed air is available for plant use

Filtration

To protect the desiccant bed a coalescing filter is required upstream of the dryer to remove any liquid water and/or vapors that have been ingested by the compressor. To protect downstream equipment from desiccant dust or “fines”, a particulate filter downstream of the dryer also is also recommended.

While on the topic of filtration I would like to interject my personal opinion that a heated type regenerative dryer should NOT be used with lubricated type air compressors.  I have witnessed instances where oil contamination from the compressor reached and collected on the desiccant.  This not only renders the desiccant useless but is also a fire hazard as bed temperatures can reach over 400 degrees F.