PROCESSING METHOD OF SECONDARY GAS MIXTURE

摘要

PURPOSE: To treat a by-product gaseous mixture containing methyl chloride and methane while enhancing the utilization efficiency of a thermal oxidation unit by separating the mixture in accordance with methyl chloride content and thermally oxidizing a high methyl chloride content gas. CONSTITUTION: This by-product gaseous mixture containing methyl chloride and methane is produced when methylchlorosilanes are formed from silicon and methyl chloride. The by-product gaseous mixture is first fed to a prefilter 1 to remove hydrolyzable silanes and then the mixture is sent to adsorption columns 2-5 through flow rate regulators 7. In columns 2-5, the mixture is brought into contact with an adsorbent which reversibly adsorbs methyl chloride to adsorb methyl chloride. The pressure of the columns 2-5 is then reduced to desorb a mixture enriched in methyl chloride and this mixture is sent to a thermal oxidation unit through a serge tank 6, kept at 870-1,200 deg.C, preferably 980-1,100 deg.C and thermally oxidized.