PROCESS FOR PURIFYING THE OFF-GASES FROM INDUSTRIAL FURNACES, ESPECIALLY FROM WASTE INCINERATION PLANTS

摘要

Abstract of the DisclosureA process for purifying the off-gases from indus-trial furnaces and especially from waste incineration plantsis described in which process the off-gases which containacid, neutral and/or basic pollutants in the gaseous orsolid form or in the form of a mist, are treated in anevaporative cooler and then in a dry purifier, in whichthey are freed from at least a substantial portion of thesolid pollutants, and finally in a scrubber by means ofa wash liquid. The temperature of the off-gases in theevaporative cooler is kept above the dew point, and the washliquid in the scrubber is cycled through a slurry separator,from which suspension or solution of pollutants is with-drawn from the sludge separator and fed into the evapora-tive cooler and mixed in a mixing space in the latter withthe hot off-gases. Those walls of the evaporative coolerwhich come into contact with the mixture of off-gases andrecycled suspension or solution of pollutants and whichconsist of a material that can be corroded by the saidmixture at room temperature are heated from the outside toa temperature above the dew point.As a rule the pH value of the liquid phase in the sludgeseparator and in each of the gas wash stages of thescrubber directly upstream of the said separator is keptbelow 4.