Process for purifying the waste gases from industrial furnaces, in particular from waste incinerators

摘要

The waste gases from industrial furnaces, in particular from waste incinerators, in which the waste gases contain pollutants in a gaseous or solid form or also as mist, are freed of a substantial part of the solid pollutants initially in an evaporative cooler (1) and subsequently in a dry purifier (2). The waste gases are then treated with a scrubbing fluid in a gas scrubber (3) having at least one scrubbing stage. In this process, the temperature of the waste gases in the evaporative cooler (1) is kept above the dew point of the water contained therein. The scrubbing fluid of the gas scrubber (3) is circulated via a sludge separator (4) with discharge of pollutant suspension and, parallel thereto, pollutant suspension is passed via a return line (13) to the evaporative cooler (1) and mixed with the hot waste gases. The walls of the evaporative cooler (1), which come into contact with the mixture of waste gases and recirculated pollutant suspension and consist of a material which can be corroded by the mixture below the dew point temperature, are heated from the outside to a temperature above the dew point of the water contained in the mixture. The pH of the liquid phase in the sludge separator (4) and in each scrubbing stage of the gas scrubber (3) is here kept at below 4. IMAGE