Process and appts. to purify flue gas

摘要

The flue gas is cooled until the water and the HCl it contains condenses. The condensate is sepd. and the gas is further cooled with addn. of H2O2, so that H2SO4 is formed from the H2O2 and SO2 in the gas. The H2SO4 is sepd. and the purified gas is passed out. Also claimed is an appts. to purify flue gas by the above process. The device has a gas inlet (1) linked to the first cooler (2), from which a condensate line (3) and gas line (4) leave. A gas line (5) runs to a second cooler which has a H2O2 feed (6) and H2SO4 (7) and gas (8) exit lines. The gas is moistened before or during condensation, and cooled to 45-55 deg C to condense the water and HCl. The gas remaining after condensation is cooled to 34-45 deg C before or during addn. of H2O2. This condensate is concentrated to selling grade HCl, and the vapour produced during concn. is condensed and purified in an anion-exchanger. The H2SO4 is concentrated to selling grade H2SO4. The flue gas may be freed of dust before condensation. There may be a device (27) to moisten the gas in line (1). The condensate line (3) is linked to a rectification device (19) to concentrate the HCl. From the rectification device (19), there is a conc. HCl exit line (20) and a water exit line (21) running to an anion-exchanger (22). The H2SO4 line (7) is linked to a distn. device (24) to concentrate the H2SO4.