AIR POLLUTION CONTROL SYSTEM AND METHOD FOR COAL COMBUSTION BOILER

摘要

An air pollution control system for a coal combustion boiler according to the present invention includes: a NOx removing apparatus (13) that reduces nitrogen oxide contained in flue gas emitted from this coal combustion boiler (11), an air pre-heater (14) that recovers heat in the gas, a precipitator 15 that reduces particulates from the gas, a liquid-gas contact type desulfurizer (16) that removes sulfur oxide by way of a limestone-gypsum method and reduces mercury oxide in the gas, a stack (17) that releases the gas after SOx removal to the exterior, and a solid-liquid separator (22) that extracts limestone-gypsum containing slurry (21) from the desulfurizer (16) to the exterior and performs a solid-liquid separation, where water (23) separated in the solid-liquid separator (22) is removed, and concentrated slurry (24) is sent back to the bottom of the desulfurizer (16) to make the gypsum concentration of slurry (25) equal to or higher than 10 percent in the desulfurizer (16).