초록 ▼

A process is disclosed for the recovery and reuse of heat contained in the wet exhaust gases emanating from a solids dryer or liquor concentrator, particularly one in which drying or concentration is facilitated by purging the vapor with some noncondensable gas such as air or nitrogen. Water or solv

A process is disclosed for the recovery and reuse of heat contained in the wet exhaust gases emanating from a solids dryer or liquor concentrator, particularly one in which drying or concentration is facilitated by purging the vapor with some noncondensable gas such as air or nitrogen. Water or solvent vapor in the moist exhaust mixture is separated from the noncondensable gas or gases by preferentially passing the vapor through a semipermeable membrane. The water or solvent vapor is then compressed and subsequently condensed in a heat exchanger, permitting recovery of its latent heat of vaporization for reuse in the evaporation process. In a drying process, this recovered energy is conveniently used to reheat the dry gases that exit from the membrane separator, permitting the hot, dry gases to be recirculated through the dryer. Alternatively, an indirect heat exchanger may be used to transfer this heat to the material being dried. In an evaporative process for the concentration of a liquor, the recovered energy may be used either to preheat the dry purge gases or to heat the dilute liquor being concentrated.

대표청구항 ▼

An energy-efficient process for the recovery of latent heat from a drying process comprising (1) contacting a material containing a volatile liquid with a gaseous drying medium and supplying heat to said drying medium or to said material and thereby producing an exhaust mixture of noncondensable gas

An energy-efficient process for the recovery of latent heat from a drying process comprising (1) contacting a material containing a volatile liquid with a gaseous drying medium and supplying heat to said drying medium or to said material and thereby producing an exhaust mixture of noncondensable gas and condensable vapor, (2) separating the condensable vapor in said exhaust mixture by passing it through a nonporous nonionic polymeric membrane which is substantially permeable to said condensable vapor and substantially impermeable to said noncondensable gas, (3) transferring said separated condensable vapor, together with the latent heat of condensation contained therein, to a compressor, (4) compressing in said compressor said separated condensable vapor, and (5) condensing said separated condensable vapor by heat exchange, thereby recovering the latent heat of condensation of said separated condensable vapor.