Patent ID: 8372180

Claim:
A process for controlling the moisture content of a supply gas for use in drying a product, which process comprises the steps of: (a) providing the supply gas; (b) optionally heating the supply gas; (c) determining the temperature and the moisture content of the supply gas; (d) passing the supply gas through a rotating zeolite desiccant wheel which comprises at least an adsorption section through which the supply gas passes and wherein moisture is adsorbed from the supply gas, a regeneration section through which superheated steam is passed to remove at least part of the adsorbed moisture from the zeolite desiccant whereby steam is obtained that comprises at least part of the moisture that was adsorbed in the adsorption section, and a flush section through which a flush gas is passed to cool the zeolite desiccant and wherein further regeneration of the zeolite takes place, whereby the rotating speed of the zeolite desiccant wheel is adjusted by a feed forward control loop on the basis of the moisture content as obtained in step (c) and the corresponding sorption isotherm of the zeolite desiccant; and (e) recovering the dehumidified supply gas as obtained in step (d).