Abstract: A selected contaminant is removed from a gas stream containing an unselected component that is also absorbed by the solvent, although to a lesser degree than the selected contaminant. In a typical application, hydrogen sulfide is removed from a natural gas stream that contains carbon dioxide as an unselected component. The process employs a solvent absorption/regeneration sequence, carried out in an absorber and regenerator, to remove the selected contaminant (hydrogen sulfide, for example) from the gas stream. The overhead gas from the regenerator has a higher concentration of the selected contaminant than the original gas stream. This contaminant rich overhead gas stream is partially employed as a recycle stream that is combined with the original gas stream, with the resulting combined gas stream being fed to the absorber.

Abstract: A gas stream containing hydrogen sulfide is combusted in a furnace to form a gas having a hydrogen sulfide to sulfur dioxide ratio of at least three to one. The gas is contacted with a conventional Claus catalyst to form elemental sulfur, which is separated and removed. The remaining gas is combined with an oxidizing gas stream and contacted with a special catalyst. The special catalyst has an active ingredient comprising a mixture of metal oxides or a mixed metal oxide, where metal is defined as at least two of the transition metals occurring in the first transition group of the periodic table. The special catalyst preferably has a spinel structure. As an option, a portion of the acid gas feed can be bypassed a point before the final reactor to ensure that the gas going to the final reactor promotes the desired catalytic action. The special catalyst oxidizes both COS and CS.sub.2 to CO.sub.2 and SO.sub.2, and converts H.sub.2 S and SO.sub.2 to elemental sulfur and water.

Abstract: An apparatus for controlling the hydrogen sulfide concentration in an acid gas stream and the hydraulic loading of a sulfur recovery unit of the type having an absorber for contacting a sour gas stream with an absorbent, a regenerator for regenerating the absorbent to form an acid gas stream and a recycle system. Embodiments using multiple absorbers and/or multiple regenerators are disclosed.

Abstract: An apparatus for controlling the hydrogen sulfide concentration in an acid gas stream and the hydraulic loading of a sulfur recovery unit of the type having an absorber for contacting a sour gas stream with an absorbent, a regenerator for regenerating the absorbent to form an acid gas stream and a recycle system. Embodiments using multiple absorbers and/or multiple regenerators are disclosed.