Consideration of blower and vacuum regeneration, from the process technological and energy requirement point of view, leads to the following result from which conclusions can be drawn: Vacuum regenerated adsorption dryers in which desorption takes place by countercurrent and associated cooling in the main direction of flow, represent the optimum achievable with present day technology as far as adsorptive drying is concerned. As the flow paths of the regeneration air are reversed for cooling after desorption, a more sophisticated electrical and mechanical control effort is called for. However, the higher investment costs resulting from this are amortised by the more favourable operating costs. In practice, this type of system can achieve pressure dewpoints down to -110°C.
