US 5,965,100 A · Process for recovery of sulfur from an acid gas stream

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. The process converts a greater percentage of hydrogen sulfide to elemental sulfur than the Claus process, and also gives greater overall sulfur recovery.

Claims24

Dependent claims

A process for recovery of sulfur from an acid gas feed stream containing at least about thirty-five volume percent hydrogen sulfide, comprising the steps of:

A) oxidizing the feed gas stream with an oxygen-containing gas stream in a furnace, forming a furnace effluent stream containing elemental sulfur and having a hydrogen sulfide to sulfur dioxide mole ratio of at least three to one and less than about six to one;
B) separating and removing the elemental sulfur from the furnace effluent stream, leaving a second gas stream;
C) contacting the second gas stream with a Claus catalyst in a Claus reactor under catalyzing conditions, thereby forming a first reactor effluent stream containing elemental sulfur;
D) separating and removing the elemental sulfur from the first reactor effluent stream;
E) combining and reacting the remaining gas of the first reactor effluent stream below about 300.degree. Celsius and without sulfur condensation with an oxygen-containing gas stream in the presence of a special catalyst comprising at least twenty percent by weight of CuCr.sub.2 O.sub.4 as an active ingredient on a carrier, thereby forming a final reactor effluent stream containing elemental sulfur;
and
F) separating and removing the elemental sulfur from the final reactor effluent stream.

4 more elements

A process for treating an acid gas feed stream containing less than about thirty-five volume percent hydrogen sulfide, comprising the steps of:

A) oxidizing the feed gas stream with an oxygen-containing gas stream in the presence of a special catalyst comprising at least twenty percent by weight of CuCr.sub.2 O.sub.4 as an active ingredient on a carrier in a thermocatalytic reactor under catalyzing conditions, thereby forming a thermocatalytic reactor effluent gas stream containing elemental sulfur;
B) separating and removing the elemental sulfur from the thermocatalytic reactor effluent stream, leaving a second gas stream;
C) combining and reacting the second gas stream with an additional oxygen-containing gas stream in the presence of the special catalyst under catalyzing conditions, thereby forming a first reactor effluent stream containing elemental sulfur;
D) separating and removing the elemental sulfur from the first reactor effluent stream;
E) combining and reacting the remaining gas of the first reactor effluent stream with an additional oxygen-containing gas stream in the presence of the special catalyst under catalyzing conditions, thereby forming a final reactor effluent stream containing elemental sulfur, the overall addition of oxygen being less than or equal to the stoichiometric amount required for production of elemental sulfur;
and
F) separating and removing the elemental sulfur from the final reactor effluent stream.

4 more elements

Dependencies are inferred from the claim text.

Process for recovery of sulfur from an acid gas stream

Life of this patent

Process for recovery of sulfur from an acid gas stream

Life of this patent

Abstract

Claims24