Sulfur recovery from gases rich in H2 S and CO2 as well as COS or organic sulfur

Claim 1

In a process for sulfur removal from hydrogen sulfide-containing gases wherein said gases may comprise a plurality of streams at least the major portion of which contains a high proportion of carbon dioxide together with carbonyl sulfide or organic sulfur compounds or both, in which process the sulfur containing constituents of said gases are converted to elemental sulfur in a Claus plant, the steps comprising: (a) passing a gas stream from step (h), optionally in combination with fresh feed gas which contains hydrogen sulfide and is low in carbon dioxide, carbonyl sulfide and organic sulfur compounds, to a Clause plant wherein the predominant part of the hydrogen sulfide contained in the gas entering said Claus plant is converted to elemental sulfur, which is recovered; (b) recovering, from said Claus plant, off-gas which contains residual hydrogen sulfide; (c) combining said off-gas with a hydrogen sulfide-containing gas which has a high content of carbon dioxide together with carbonyl sulfide and/or other organic sulfur compounds; (d) passing the combined gas streams from step (c) at a temperature in the range from 180° C. to 450° C. in the presence of a free hydrogen- and/or free carbon monoxide-containing gas over a sulfide Group VI and/or Group VIII metal catalyst supported on an organic oxidic carrier for the conversion of sulfur compounds other than hydrogen sulfide to hydrogen sulfide; (e) cooling the reduced gas mixture obtained in step (d) and passing it in a absorption zone, at a temperature below the dew point of water, through a liquid, regenerable absorbent for hydrogen sulfide at a gas velocity of 1 m/sec. or more with respect to the aerated part of the said absorption zone; (f) discharging the unabsorbed portion of the gas mixture from the process after passage through the said absorbent; (g) regenerating the hydrogen sulfide enriched absorbent, thereby producing a hydrogen sulfide-rich gas mixture and regenerated absorbent; (h) returning regenerated absorbent obtained in step (g) to step (e) for further hydrogen sulfide absorption and passing the hydrogen sulfide-rich gas mixture obtained in step (g) to the Claus plant for conversion of the hydrogen sulfide to elemental sulfur.