TREATMENT SYSTEM FOR MERCURY IN FLUE GAS

摘要

Provided is a system for removing mercury in exhaust gas, where the system removes Hg contained in an exhaust gas from a boiler and comprises the following: a heat exchanger (AH) (18) which subjects an exhaust gas (12) from a boiler (11) to heat exchange; a dust collector (19) which removes particulate matter present in the exhaust gas (12); a wet-type desulfurization device (21) which removes mercury oxide (Hg2+) present in the exhaust gas (12) by means of an alkali absorption liquid and which removes sulfur oxides present in the exhaust gas; and an HBr compound supply means (50) which supplies HBr, which is a Br compound, to a flue (13) that discharges exhaust gas from a boiler outlet. The concentration of bromine in the alkali absorption liquid in the wet-type desulfurization device (21) is increased to a prescribed concentration or higher. Consequently, mercury present in the exhaust gas is stabilized in the form of Hg2+ ions in a gypsum slurry solution discharged from the wet-type desulfurization device (21).