SYSTEM AND METHOD FOR TREATING DISCHARGE GAS FROM COAL-FIRED BOILER

摘要

A discharge gas treatment system for coal-fired boilers which comprises: a denitration device (13) in which nitrogen oxides contained in a discharge gas discharged from a coal-fired boiler (11) are removed with ammonia (12) added thereto; an air preheater (14) which recovers heat from the gas from which the nitrogen oxides have been removed; a dust collector (15) which removes soot/dust from the gas from which heat has been recovered; a gas/liquid contact type desulfurizer (16) in which sulfur oxides contained in the gas from which dust has been removed are removed by the lime-gypsum method and, simultaneously therewith, mercury oxide is removed; and a chimney (17) through which the purified gas which has undergone desulfurization/mercury removal is discharged outside. In the system, an oxidizing agent is added to the inside of the desulfurizer (16) or to a slurry (21) containing limestone-gypsum which has been discharged outside.