DEHYDRATION AND TREATING : AIR DRYERS

AIR DRYERS 2018-10-03T11:00:20+00:00

Heatless Dryer

This series operates on the “Pressure Swing” principle. These dryers regenerate the desiccant bed by expanding a portion of dried air to atmospheric pressure. This swing in pressure, when passed through the desiccant picks up moisture from desiccant pores which were loaded with moisture in the previous adsorption cycle. The portion of dried air quantity depends on line pressure, cycle time and purge time with a basic premise that the volume of purge must be more than the feed air for adsorption. High-pressure versions can go up to 300 bar inlet. For capacity please consult us.

Pressure Bar(g) Temperature Deg C Flow Nm3/hr Pressure Dew Point Deg C
5 to 17.5 40 to 60 1000 to 9000 (-) 20 to (-) 70 or lower

Internally Heated Dryer

This series comprises of heat regenerative dryers. A heater is installed in the desiccant bed. Wet inlet air is directed through the drying tower where moisture is adsorbed on the desiccant. A small portion of the dry outlet air is diverted to the regenerating tower. It flows downward over the heater and then upward through the bed where it collects moisture from the desiccant. Wet air is exhausted to the atmosphere through a purge valve.

Pressure Bar(g) Temperature Deg C Flow Nm3 / hr Pressure Dew Point Deg C
5 to 17.5 40 to 60 2000 to 9000 (-) 20 to (-) 70

Blower Reactivated Dryer

Wet air from compressor is passed through one of the beds which are in the adsorption mode and thus dries the air. For regeneration, normally atmospheric air is used, through the blower. (Regeneration at a pressure in a closed loop is also possible). Blower starts and the air is passed through the bed. After regeneration, moisture-laden air is exhausted to the atmosphere through a silencer. When the regeneration temperature is reached at the outlet of the bed, the heater will be switched off and a blower now continues blowing air through the same tower to cool down the reactivated desiccant. These dryers can also be designed for countercurrent heating and co-current cooling in open & closed loops.

Pressure Bar(g) Temperature Deg C Flow Nm3 / hr Pressure Dew Point Deg C
0.1 to 17.5 40 to 60 5000 to 40000 (-) 20 to (-) 70 or lower

Heat of Compression Dryer

In this type of dryers, hot air from the last stage of a compressor is fed to one of the towers (partially / fully depending on design), which desorbs the previously loaded bed. The air is then passed through an intermediate cooler and high-efficiency separator. The air in case of full flow system goes straight to the other tower and gets dried. In case of partial flow, only part of the air goes through the regeneration bed, and after cooling, it gets mixed with the main incoming air. Control of this dryer is critical as no present time is taken for regeneration. Moreover, regeneration depends on compressed air demand and hence in each cycle, the flow has to be measured and the cycle time has to be extended proportionately (in case flow required per unit time is lower than the design flow)

Pressure Bar(g) Temperature Deg C Flow Nm3 / hr Pressure Dew Point Deg C
5 to 30 80 and above 5000 to 40000 (-) 20 and lower

Split Stream Dryer

Compressed air coming from a compressor is split into two different streams. Regeneration flow is fixed and calculated flow. A flow transmitter is used to maintain the regeneration flow, irrespective of the demand. Regeneration air is then passed over an electric heater and this hot air is diverted to pass through the bed, in countercurrent mode where it picks up moisture from the bed. This moisture is adsorbed and dry air goes out to the network. During cooling, the heater is switched off and the air is diverted to enter bed in co-current mode. These can also be designed to counter current heating and co-current cooling.

Pressure Bar(g) Temperature Deg C Flow Nm3 / hr Pressure Dew Point Deg C
5 to 17.5 40 to 60 4000 to 25000 (-) 20 and lower