5.4.6.1. Cold regeneration


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Fig. 5.11: Adsorption material after 5min. drying time
With cold regeneration the drying and regeneration time is around 5min. For this reason the moisture only deposits on the outer surface of the drying agent.

Cold regeneration adsorption dryers operate according to the pressure alternation process. With this method the desorption ( regeneration ) takes place without additional input of heat. A part of the dried volume flow is branched off. This part-flow relaxes to a pressure of just over 1 bar and is thus extremely dry. This dry air then flows through the regeneration drying
tankB. In this process it takes on the moisture stored in the drying agent and directs it out into the open through an outlet valve.
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Fig. 5.12: Op. diagram of an adsorption dryer,
cold regeneration
Features
    • Economical on smaller systems with low volume flows.
    • Simple dryer construction.
    • Can be used at high ambient temperatures.
    • Low volume of drying agent.
      Drying and regeneration times approx. 5 min.
    • High operating costs.
      The regeneration air is taken from the pneumatic system and can not be used further .
    • Regeneration without outside energy.
    • The percentage ratio of regeneration air to the output of the compressor falls with a higher final compression pressure.

These values are physically fixed and it is not possible to go below them. They are taken from the correlation between air moisture and compressed air pressure relief.
    • Prefiltration of intake air.
      A prefilter removes most of the oil, water droplets and particles of dirt.
    • Postfiltration of dried compressed air.
      Drying material taken with the compressed air from the drying tank must be filtered out.