Scrubber for the desulfurization of exhaust gases

A scrubber for removing sulfur compounds from a gas, comprising:

• a vertically extending column having a lower portion and an upper portion, inlet means connected and communicating with said lower portion for feeding sulfur bearing gases to said column, said sulfur bearing gases passing into said upper portion, outlet means connected to and communicating with said upper portion for discharging the scrubbed gas;
• means in said upper portion of said column for contacting said sulfur bearing gases with a scrubbing liquid containing a sulfur-binding substance whereby a scrubbing liquid containing sulfur compounds descends in said column through said lower portion;
• means forming a sump in said lower portion of said column for collecting the scrubbing liquid, said sump being provided with an outlet for a sump product consisting primarily of calcium sulfate;
• a grate formed by a multiplicity of mutually parallel closely spaced oxygen-inlet ducts formed in said sump and subdividing said sump into an oxidation zone above said grate wherein oxygen from said ducts reacts sulfite in the liquid in said oxidation zone to form sulfate and into a reaction zone below said grate where said sulfate is precipitated out as calcium sulfate in said product, said ducts being downwardly open upwardly convex hoods supplied via oxygen supply means and formed with upwardly directed orifices for discharging oxygen into the liquid in said oxidation zone, the spacing between said hoods being sufficiently limited to prevent backflow from said reaction zone to said oxidation zone, said inlet for said gas being located below said means for contacting but above said sump, said outlet for said gas being located above said means for contacting;
• and
• means for introducing an additive into said reaction zone below said grate for inducing the precipitation of the sulfate from said liquid as the calcium sulfate of said product.