PROCESS OF REMOVING HYDROGEN SULFIDE FROM EXHAUST GAS AND FOR PRODUCING SULFUR BY THE CLAUS PROCESS

摘要

A feed gas is partially burnt with oxygen-containing gas in a thermal Claus process plant, in which temperatures in the range of 850 to 1350.degree.C is maintained. Product gas which has been produced is passed through a catalytic Claus process plant (Claus catalysis plant), from which sulfur is withdrawn. The exhaust gas from the Claus catalysis plant is supplied to a desulfurizing plant. The sulfur compounds in the exhaust gas of the desulfurizing plant axe converted to SO2 in a thermal aftertreating unit. When the rate of the H2S-containing feed gas is below a limit, which is between 20 to 35% of the total rate of feed gas permissible for the thermal Claus process plant, then recycled exhaust gas from the desulfurizing plant (recycle gas) is admixed to the feed gas at such a rate that the rate of the mixed feed and recycle gases exceeds that limit. The recycle gas is suitably heated to 200 to 400.degree.C before it is mixed with the feed gas.