To reactivate the absorber, a portion of the product dry gas is depressurized and passed through. The feed gas pressure should be at least 7 kg/cm2g.
The amount of regeneration gas depends on the pressure and temperature of the supply gas. In order to avoid pressure shock , the absorber is pressurized before change over.
Salient features
Low capital cost
No heater required
Power is required for control purposes only
Ideally suitable for hazardous area
Desiccant does not experience thermal shock hence LONGER Life
Minimum maintenance as no heater, blower, or motor.
No Loss Purge Type
A part of the feed gas is heated and used for reactivation. After cooling and moisture separation, the reactivation gas is ultimately combined with the feed stream in a distributor before being fed into an absorber for adsorption.
Salient features
No blower.
No pressurization and depressurization.
No pressure difference across tour way valve.
No contamination from foreign gas.
No loss of dry Air.
Ideally suited for large capacity plant.
Open Loop Blower Type
While one absorber is kept under adsorption, the other is regenerated by passing hot air utilizing a blower through a heater and finally vented to the atmosphere. There is provision for pressurization and depressurization.
Salient features
Adsorbers can be kept regenerated before commissioning.
Adsorption is independent of regeneration.
No Joss of compressed air.
Closed Loop Blower Type
Operation of this system is similar to the open loop blower type except that reactivation is done through a cooler and moisture separator in a closed loop.
Salient features
No contamination from atmosphere.
Desiccant bed can be thoroughly cooled.
No appreciable change in quality of dry gas just after change over.
Product Purge Type
This method is exceptionally well suited for high pressures because only a small amount of product gas needs to be purged for reactivation. The saturated adsorber is depressurized for reactivation. A small quantity of dried gas is throttled, heated by means of a heater and passed through the adsorber.
For gases other than air, the purge gas can be recycled back to the suction of the compressor.
Salient features
No moving parts such as Blowers and motors.
Longer cycle time.
No contamination with foreign gases.
Due to depressurisation, regeneration can be done with nominal heating.
