SYSTEM FOR MAKING FLUOROGAS-CONTAINING MIXTURE HARMLESS

PROBLEM TO BE SOLVED: To reduce the amount of energy required of heating, downsize the apparatus, and enhance the treatment efficiency by brining a highly active acidic or oxidizing gas contained in a waste gas into contact with a treating agent to separate and make the acidic or oxidizing gas harmless, then subjecting the waste gas to concentration and volume reduction, and decomposing and making it harmless. SOLUTION: In treating a mixed gas containing a perfluoro compound, a hydrofluorocarbon, an acidic gas, an oxidizing gas, or the like, the mixed gas is treated with a dry harm-eliminating apparatus 1 and then is introduced through a breakthrough detector 2 into a filter apparatus 5 to remove dust. Then, after compressed with a compressor 7, the gas is introduced into gas separation membrane apparatuses 10, 10' each equipped with a nitrogen separation membrane. An inert gas, such as nitrogen, separated in a large amount by the permeation through the membrane is inspected with a PECs concentration meter 11 and, after safeness is confirmed, is discharged into the atmospheric air. On the other hand, a concentrated gas flow which does not permeate the nitrogen separation membrane is introduced through a flow rate controller 12 into a thermochemical decomposition appartus 14, where PFCs is decomposed.