EXHAUST GAS TREATMENT APPARATUS AND ORP CONTROL METHOD THEREFOR

摘要

This exhaust gas treatment apparatus has: a redox agent supplying means for supplying a redox agent, which produces hydrogen chloride and ammonia when vaporized, to a discharge flue for the exhaust gas from a boiler; a reduction/denitration device that has a denitration catalyst for reducing the nitrogen oxide in the exhaust gas using ammonia and oxidizing the mercury in the presence of hydrogen chloride; a wet desulfurization device for absorbing and removing the sulfur oxide in the exhaust gas and the oxidized mercury in the reduction/denitration device using an absorbing solution; an oxidation reduction potential (ORP) meter for measuring the ORP of the absorbent; a solid-liquid separating means for separating the solids and the mercury from the liquids in the desulfurization waste water discharged from the wet desulfurization device; a separated-liquid return line for returning the separated liquids separated by the solid-liquid separating means to the wet desulfurization device; an oxidizer supplying means for supplying an oxidizer to the separated liquids that are sent to the wet desulfurization device; and a controlling means for adjusting the supply levels of the oxidizer to control the ORP of the absorbent.