PROCESS AND DEVICE FOR REMOVING MERCURY IN COMBUSTION EXHAUST GAS OF COAL

摘要

PROBLEM TO BE SOLVED: To make a process and a device thereof applicable to an existing power station from the viewpoint of economy and improve the mercury removing rate by preliminarily adding a chlorine compound into coals and burnt and then removing soot and dust in the exhaust gas in a dust collector set on the post-stream of a combustion system and recovering the same. SOLUTION: A calcium chloride B as a chlorine compound from a line 3 is added into a coal A fed from a coal feed pipe 1 into a boiler 2. Then exhaust gas D in the boiler 2 containing soot and dust C such as ash particles is introduced into an electric dust collector 7 through a denitration equipment 4, an air heater 5 and a heat recovery section 6 to remove the soot and dust C in the exhaust gas. A part of a mercury in the exhaust gas is made to adhere on the surfaces of soot and dust and recover the same together with the soot and dust C. Also the exhaust gas containing the soot and dust not removed therefrom is introduced into a desulfurizing equipment 8 to reduce SO2 in the exhaust gas. The temperature of the exhaust gas exhausted out of the desulfurizing equipment 8 is raised by a reheating section 9, and then the exhaust gas is exhausted out of a stack 10.