METHOD FOR TREATING INCINERATION EXHAUST GAS

PROBLEM TO BE SOLVED: To make adjustable the amount of a smoke-scrubbing drain which contains highly concentrated impurities and is supplied to an impurity removing installation and thereby reduce the scale of the removing installation and further make effective use of resources by sending the smoke-scrubbing drain to the impurity removing installation and on the other hand, using part of the smoke-scrubbing drain which contains a low concentration of impurities as a cooling water for the interior of a flue gas treatment column and discharging the used drain. SOLUTION: An incineration exhaust gas is supplied to the lower chamber 4 of a flue gas treatment column 1 and a cleaning water is atomized to remove impurities while the exhaust gas ascends sequentially from an intermediate chamber 3 and an upper chamber 2 in that order. After that, the smoke-scrubbing drain generated in the lower chamber 4 is stored in a drain tank 5 and the cleaning drain generated in the intermediate chamber 3 is stored in a circulation tank 6. In this case, the cleaning drain generated in the upper chamber 2 is divided to be supplied to the circulation tank 6 and a receiving tank 7 through water meters 8, 9. Next, the cleaning drain stored in the drain tank 5 is circulated by a pump 10 as a cleaning water for the lower chamber 4, and the cleaning drain supplied to the circulation tank 6 is circulated by a pump 11 as a cleaning liquid for the intermediate chamber 3. On the other hand, the smoke-scrubbing drain supplied to the receiving tank 7 is sent to a cooler 12 by a pump 14 as a cooling water and used to cool the smoke-scrubbing drain to be supplied to the lower chamber 4.