Optimising gypsum quality during wet flue gas desulphurisation

摘要

Optimising the gypsum quality during a wet flue gas sulphurisation of brown coal fired vessel comprises treating the flue gas (2) in an absorber (1) with scrubbing water suspension containing limestone and converting sulphur dioxide (SO2) into calcium sulphate-dihydrate crystals by introducing atmospheric air. The brown coal has a lowest possible sulphur content of 0.5%, the limestone a calcium carbonate content of 94%, and a granulation of 90 mu m. The pH value in the sump (13) of the absorber is adjusted to exactly 5.4-5.5.