Method and plant for the desiccation of drying gas

Claim 1

In a method of removing moisture from a drying gas used for the drying of solid substances, particularly granular plastics, in which the gas after flowing through the substance is dried in an adsorption drying agent, thereafter heated and finally conducted through the substance to be dried, and in which the adsorption drying agent, after it has reached a given degree of moisture, is replaced by a newly regenerated drying agent while it is itself regenerated by the application of heat, the improvement comprising: (a) conducting said drying gas sequentially through a first bed of drying agent and through a second bed of drying agent; (b) dividing said gas stream after the second bed of drying agent into a first and second partial gas stream; (c) conducting said first partial gas stream of the drying gas, behind the second bed of drying agent, through a newly regenerated third bed of drying agent; (d) thereafter returning said first gas stream, behind said third bed, to said second partial stream of gas which has bypassed said third bed of drying agent; (e) conducting said united gas streams to the substance to be dried; (f) regenerating a fourth bed of drying agent with a heating medium; and (g) replacing said four beds of drying agent in constant sequence upon complete saturation of said first bed of drying agent.