Process for separating off acidic constituents downstream of fossil fuel plants

摘要

It is known that in combustion boilers which bear acidic constituents in the flue gas, these are bound by blowing in lime substances. However, the degree of binding is far below 30% and thus in no way corresponds to the values demanded. In order to eliminate this disadvantage and to separate off the acidic constituents, in particular SO2, eg. at 90@, from the crude gas stream, according to the invention it is proposed that the loaded dust-containing crude gas stream from a coal boiler is predominantly separated from the ash via a cyclone (1) and an additive, preferably hydrated lime, is fed downstream of the cyclone station to a contacting section (8) which opens out into a chemisorption filter (3), the used lime from the filter (3) being collected in a silo (5) and fed again to the cyclone station, and the cyclone station being designed in such a way that the vortex chamber of the cyclone (1) contacts the as yet unreacted fine dust, eg. hydrated lime, with the crude gas, and thus forced multiple contacting with circulated used lime for SO2 binding is imposed upon the contact section (2) and the chemisorption filter (3). <IMAGE>