| 摘要 |
The invention describes a process of at least substantially waste-air- and waste-gas-free drying of a water-containing material through the latter's direct contact, in a drying zone, with a circulating stream of a hot-gas mixture that contains superheated water vapor mixed with at least a second drying gas, in particular nitrogen and/or air, wherein the vaporized water is separated out and the preferably indirectly reheated hot gas mixture is directed back into the drying zone. The process is characterixed in that a portion of the gas stream of the first circuit sketched above is diverted after the drying zone, this partial stream is cooled to the point of at least partial condensation of its water content and is separated from the aqueous condensate, and the remaining gas stream (second circuit) is fed back into the circuit of the hot gas mixture. Thus, preferably at least a portion of this cooled gas stream is used as auxiliary agent in the further course of the drying process. The invention also pertains to the use of this modified drying process on any materials, but especially in the drying of temperature-sensitive goods with material temperatures under 100 DEG C. |
