Process for scrubbing out SO2, HCL, HF, NOx and other pollutants from the flue gas downstream of, preferably, fossil-fuel power stations

摘要

The invention is based on the finding that in the simultaneous wet removal of SO2 and NOx from flue gases, in particular downstream of fossil-fuel power stations, with the use of a scrubbing liquid which contains limestone or hydrated lime, monobasic or polybasic carboxylic acids and ethylene diamine tetracetic acid (EDTA), the separation out of NOx can be considerably improved if the ratio of NOx (calculated as NO) to SO2 is at least 1 to 2. In order to establish this ratio, as required, according to the invention the CaSO4 . 2 H2O produced in the flue gas desulphurisation is completely or partly recycled into the combustion chamber of the power station in which the temperature is 1200 DEG C or above.