초록 ▼

In a process of decreasing the sulfur content of exhaust gases obtained during the recovery of sulfur from acid gases containing H2S and other S-containing compounds in the Claus process, the acid gases which contain H2S and other S-containing compounds are reacted in a Claus plant to form elemental

In a process of decreasing the sulfur content of exhaust gases obtained during the recovery of sulfur from acid gases containing H2S and other S-containing compounds in the Claus process, the acid gases which contain H2S and other S-containing compounds are reacted in a Claus plant to form elemental sulfur. A gas which contains H2S or SO2 is subsequently added at a controlled rate to maintain a stoichiometric ratio of 2:1 of H2S to SO2 in the tail gas from the Claus plant. The gas which contains H2S or SO2 may be added to the tail gas from the Claus plant or before the last contacting stage of a multistage Claus plant. During the addition of a gas which contains H2S, the Claus plant can be operated at an H2S to SO2 ratio of or below 2:1. During the addition of a gas which contains SO2 the Claus plant can be operated at an H2S to SO2 ratio of or above 2:1. The H2S and SO2 contained in the tail gas are chemically reacted to form elementary sulfur in a tail gas-desulfurizing plant and the sulfur is withdrawn.

대표청구항 ▼

A process for decreasing the sulfur content of an exhaust gas released after the recovery of sulfur from an acid gas containing H2S reacted with an oxygen-containing gas stream in a Claus plant which comprises withdrawing from said Claus plant a tail gas containing H2S and SO2 at a molar ratio of up

A process for decreasing the sulfur content of an exhaust gas released after the recovery of sulfur from an acid gas containing H2S reacted with an oxygen-containing gas stream in a Claus plant which comprises withdrawing from said Claus plant a tail gas containing H2S and SO2 at a molar ratio of up to 2:1, adjusting the molar ratio of H2S:SO2 to virtually exactly 2:1 in said tail gas by adding a gas containing H2S to form a stoichiometric gas mixture, analyzing said stoichiometric gas mixture to determine the concentration of H2S and SO2 and, according to said analysis, adjusting the amount of said gas containing H2S to be added, the maximum amount of said gas containing H2S added being less than 5% of the acid gas fed into the Claus plant, catalytically reacting said stoichiometric gas mixture to form elementary sulfur and separately withdrawing said elementary sulfur and said residual gas, said gas containing H2S being added (i) either to the tail gas exiting from the Claus plant, or (ii) before the last contacting stage of a multi-stage Claus plant. A process according to claim 1, wherein the tail gases from two or more Claus plants are conducted to a common tail gas-processing plant and jointly desulfurized therein.