FLUE GAS DESULFURIZATION APPARATUS

摘要

PROBLEM TO BE SOLVED: To reduce the burden for treatment of suspended solids(SS) in a waste water treatment apparatus by disposing a filtrate bypassing line for returning the filtrate separated from gypsum to an absorption column when the SS concn. of overflow water of a gypsum thickener of a gypsum recovering device exceeds a planned value. SOLUTION: The flue gas desulfurization apparatus using calcium carbonate as an absorbent for absorbing and removing SO2 from the waste gasdischarged from a coal firing boiler, etc., has the absorption column 3 which is formed with a liquid reserving section 1a of an absorbent liquid 1 in the lower part and a formed with spray nozzles 2 and so forth in the upper part. The apparatus is equipped with an oxidizing air blower 5 for supplying oxidizing air to the liquid reserving section 1a and the gypsum recovering device 7 for recovering the gypsum 6 from the absorbent liquid 1 extracted from the liquid reserving section 1a. The gypsum recovering device 7 is provided with the filtrate bypassing line 30 for returning the filtrate 19 separated from gypsum 6 to the absorption column 3 when the SS concn. 29 of the overflow water 13 of the gypsum thickener 16 exceeds the planned value. As a result, the burden of the respective apparatus is reduced.