Patent ID: 7625539

Claim:
A process for producing a purified gas stream from a feed gas stream comprising contaminants, the process comprising the steps of: (a) removing contaminants from the feed gas stream to obtain the purified gas stream and a sour gas stream comprising H 2 S and RSH wherein R is an alkyl group or an aryl group; (b) separating the sour gas stream comprising H 2 S and RSH into a gas stream enriched in H 2 S and a residual gas stream comprising RSH; (c) converting H 2 S in the gas stream enriched in H 2 S to elemental sulphur in a Claus unit, thereby obtaining a first off gas stream comprising SO 2 ; (d) converting SO 2 in the first off gas stream comprising SO 2 to H 2 S in a Claus off gas treating reactor to obtain a second off gas stream comprising H 2 S; and (e) converting RSH from the residual gas stream comprising RSH to H 2 S in a RSH conversion reactor which reactor is separate from and in addition to said Claus off-gas treating reactor, to obtain a residual gas stream comprising H 2 S, wherein at least one of the operating conditions of the RSH conversion reactor is different from the corresponding operating condition of the Claus off-gas treating reactor.