Method for the recuperation of thermal energy contained in the vapours of multi-step evaporators used in thermal mass-transfer processes, and device for carrying out this method

摘要

A method and apparatus for recovering heat energy which is contained in the vapors of multi-stage evaporators utilized for thermal material-separation processes. According to the method, the vapors are supplied to at least one expulsion stage and to at least one vaporizing stage, whereby in the expulsion stage easily volatized or low boiling components of a multi-material mixture are vaporized, and in the vaporizing stage, at a pressure greater than the pressure in the expulsion stage, easily volatized components entering the vaporizing stage are vaporized; furthermore, the vaporous, easily volatized components at the higher pressure are supplied, along with the residue or remainder (the so-called residual mixture) of the multi-material mixture existing after the expulsion procedure, to an absorption stage; in addition, heating-steam or vapor is recovered by means of the heat resulting during the absorption stage. The apparatus for carrying out the foregoing method includes an expeller, in which easily volatized components of a multi-material mixture are vaporizable by introduction of vapors withdrawn from a multi-stage evaporator, and which is connected, by way of a condenser for liquefication of the entering vaporous, easily volatized components, with an evaporator which is likewise heated by vapors; the vapor discharge of the evaporator is connected to an absorber. The heat-absorbing side of the expeller and the heat-emitting side of the absorber, have in common a supply line for the residual mixture resulting during the expulsion procedure, and also a return line for the multi-material mixture which is saturated after the absorption procedure. Furthermore, the heat-absorbing side of the absorber is equipped with a steam or vapor generator.