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Sahara Air Products

Economics of Air Drying

Presented in a 10-part series, this informative article

takes a look at wet compressed air and

how various types of dryers function to dry the air.



Part 4: Refrigerant



By Charles Henderson, Vice President

Henderson Engineering Co., Inc.


Instruments, electronics, cryogenics, pharmaceuticals, flash freezing, and frozen outdoor air lines are all examples of why regenerative dryers are needed in industry. A regenerative dryer will deliver a dew point of -40°F and can go as low as -100°F at line pressure.


There are several different types of regenerative dryers, but they all conform to the same basic concept. A regenerative dryer consists of two pressure vessels, or towers, filled with a regenerable desiccant. This desiccant is like a sponge, in that it is able to soak up water; then after being squeezed or regenerated, it is once again able to soak up water. The desiccant in one tower is on-stream drying the air, while the desiccant in the other tower is off-stream being regenerated. The two towers are interlinked with switching valves, so that when the desiccant in the drying tower is saturated, the valves switch the flow into the tower that has just been regenerated. This all happens automatically, assuring you of the highest quality air all of the time. See Illustration 3 below.

Acrobat icon Regenerative Dryer Pressure Vessels Get Adobe Reader

Illustration 3: Regenerative Dryer Pressure Vessels