Counterflow Regeneration

Kaeser's up flow drying and down flow regeneration extends desiccant service life and assures consistent outlet dew points. The counter flow arrangement also controls the accumulation of liquid water in the desiccant beds. Because gravity and low velocities allow moisture to settle in the bottom of the desiccant vessel, it is safely discharged from the system when the tower depressurizes for regeneration. This design also ensures that the driest portion of the desiccant bed is nearest the dryer outlet at switchover, and allows purge air to be evenly distributed throughout the desiccant bed, providing more effective regeneration.

How It Works:

The dryer alternately cycles the compressed air flow through twin desiccant towers. As the vapor-laden air enters and flows upward through one tower, the moisture is adsorbed onto the desiccant. Clean, dry air flows from the dryer downstream into the compressed air system.

While one desiccant chamber is in the drying cycle, the other chamber goes through a regeneration cycle. Three methods of regeneration are available:

KAD dryers use a portion of the dry outlet air (about 15%), which is reduced in pressure through an orifice, further reducing its dew point. This extremely dry air, aided by the heat of adsorption, regenerates the desiccant.

KED dryers use a smaller portion of dry outlet air (about 7%), which is also reduced in pressure through an orifice and then heated to 375°F. This hot, extremely dry air passes through the bed regenerating the desiccant.

KBD dryers use a regenerative blower to move ambient air through a heater where its temperature is increased to 375°F, and then through the bed, regenerating the desiccant.

In all cases, after regeneneration is complete, the desiccant chamber is gradually re-pressurized and put on-line for another drying cycle.