Process for limiting chloride buildup in SO2 scrubber slurry

摘要

In the process of scrubbing flue gas to remove pollutants therefrom by contacting the flue gas (1) with an aqueous reactant mixture (11) of water and pollutant absorbent, water soluble chloride impurities present in the flue gas (1) and make-up water (40) tend to build-up as the supernatant liquor (21) from the spent reactant mixture (13) dewatering cycle is recycled for mixing with unreacted pollutant absorbent (30) to form additional reactant mixture for contacting with the pollutant laden gas. The build-up of chlorides in the reactant mixture is controlled by passing a purge stream (23) of the choride containing liquor (21) in contact with a hot drying gas (1, 9) so as to evaporate the water and crystallize the chloride impurities in the purge stream. The crystallized particles of chloride salt are then removed from the drying gas as a dry solid (50, 52).