METHOD FOR RECOVERING HYDROGEN BROMIDE IN WASTE GAS IN PRODUCTION PROCESS FOR BROMINE ACCORDING TO SULFUROUS ACID GAS METHOD

摘要

PURPOSE:To efficiently recover bromine contained in a waste gas from an absorption column by regulating the feed rate of chlorine fed to an absorption step in a production process for the bromine by a sulfurous acid gas method and regulating the sulfurous acid gas concentration in an outlet gas from a recovery step. CONSTITUTION:A mixed gas 1 of bromine and air produced from a generation step of bromine production equipment by a sulfurous acid gas method and sulfurous acid gas 2 are added into a gas inlet duct 5 for an absorption column 4 so as to be homogeneous. The sulfurous acid gas concentration in a gas in a waste gas cylinder 19 of a scrubbing column is measured with a nondispersion infrared type SO2 analyzer 15, etc., in order to discharge the waste gas at a prescribed value or below of the sulfuric acid gas concentration to be excess. The feed rate of chlorine gas 3 for regulating the waste gas fed to the absorption column is regulated according to the aforementioned concentration, e.g. by feedback control. Thereby, the sulfurous acid gas concentration in the gas in the waste gas cylinder 19 of the scrubbing column is regulated so as to provide, e.g. =10ppm.