Regenerative Desiccant Dryers
Regenerative Desiccant Dryers go by various names: regen dryers, twin tower dryers, desiccant dryers, pressure swing adsorption (PSA) dryers, temperature swing (TSA) dryers. In any case, the two towers operate alternately. Wet compressed air flows through the desiccant bed of one tower, while the desiccant in the other tower is being regenerated or stripped of accumulated moisture. Regeneration of the desiccant bed is accomplished in various ways: by a purge of dry air drawn from the outlet of the on-line tower; by externally heated purge air; by internal heaters; by atmospheric air blown through an external heater and forced through the off-line tower; or with steam. The desiccant bed consists of a solid adsorbent material, such as activated alumina, silica gel, or molecular sieve.
Of the three compressed air dryer types, regenerative desiccant dryers supply the lowest dew point, usually
-40ºF and, if required, as low as -100ºF pressure dew point. Regenerative desiccant dryers are often specified to protect instrumentation and control systems, laboratory equipment or moisture-sensitive process materials. These dryers can also protect against air line freeze-ups in outdoor lines in the most severe conditions.
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Heatless
Desiccant Air Dryers
Heatless desiccant dryers, or pressure swing adsorption (PSA) dryers use a purge of dry air from the outlet of the on-line tower to regenerate the off-line tower. While the compressed air is being dried in one tower, the desiccant in the other tower is being regenerated. These dryers provide standard line-pressure dewpoints of -40°F, and can provide dewpoints as low as -100°F. Heatless desiccant dryers typically have the lowest initial cost of all regenerative desiccant dryers.
We have 4 ranges of heatless desiccant dryers:
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Externally Heated/Blower Purged Dryers
These dryers use hot atmospheric air from an externally mounted blower and heater to regenerate the desiccant. No compressed air is required for regeneration. Standard units available from 350 SCFM to 10,000 SCFM and larger. |
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Internally Heated Dryers
These dryers have electric heaters inside the desiccant beds. A portion of the dry outlet air, expanded to atmospheric pressure, is diverted to the regenerating tower where it is heated as it flows through a heater isolation tube. This air is then directed through the desiccant bed where it strips off accumulated moisture. Standard units available from 150 SCFM to 3,000 SCFM. |
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Externally Heated Purge Dryers
These dryers use a portion of the dried compressed air passed through an external heater for purge, and can be switched to a Heatless Back-Up Mode while the heater is being serviced. Standard units available from 150 SCFM to 5,000 SCFM.
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