METHOD FOR TREATING EXHAUST GAS

• Main Authors: KANO HIROYA, KURATA MASAHITO, NAKAI SHIRO, KIMURA TETSUO, SATO JUN
• Format: Patent
• Language: English
• Published: 27.11.2001
• Edition: 7
• Subjects: BLASTING; COMBUSTION APPARATUS; COMBUSTION PROCESSES; FLUES; HEATING; LIGHTING; MECHANICAL ENGINEERING; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTIONRESIDUES; SEPARATION; TRANSPORTING; WEAPONS

PROBLEM TO BE SOLVED: To provide a method for treating exhaust gases which is capable of removing the oxidative gases in the exhaust gases without blowing alkaline chemical powder of slaked lime, etc., and is capable of decreasing the number of process steps in oxidation reduction of recovered molten fly ash and making a great contribution to resource recovery of heavy metals. SOLUTION: In the exhaust gas treating system for treating the exhaust gases discharged from a melting furnace 11 with a gas cooling column 14 of a dry process and a bag filter 15, an aqueous caustic soda solution of a prescribed molar ratio is sprayed as cooling water into the exhaust gases in the gas cooling column 14 to neutralize the oxidative gases in the exhaust gases by reaction with the aqueous caustic soda solution. The neutralization product of the oxidative gases and the caustic soda and the powdery salt consisting of the neutral residues of the caustic soda not reacting with the oxidative gases are taken out as gaseous cool ash to the outside of the column. The exhaust gases past the gas cooling column 14 are introduced to the bag filter 15 and the gaseous cool ash taken out of the column is blown into an inlet flue of the bag filter 15 and the oxidative gases remaining in the exhaust gases are neutralized by the reaction with the powdery salt caustic soda consisting of the neutral residues of the caustic soda failing to react with the oxidative gases in the gaseous cold ash.