Method for removing hydrogen sulfide from gas streams

Claim 1

A method for removing hydrogen sulfide from a hydrogen sulfide-containing gas stream and converting said hydrogen sulfide to elemental sulfur, which comprises: (a) contacting said gas stream with a regenerable quinone-containing washing solution so as to absorb said hydrogen sulfide into said washing solution, the washing solution introduced into contact with said gas stream comprising an aqueous solution having a pH between about 5 and about 10 and containing (1) solubilized vanadium, (2) one or more water-soluble quinones, (3) thiocyanate ions and (4) a water-soluble carboxylate complexing agent, said washing solution having a selected molar ratio of said vanadium to said quinones above about 15, said molar ratio being selected to substantially reduce the formation of contaminant sulfate salts; (b) allowing the absorbed hydrogen sulfide to react with constituents of said washing solution so as to convert said absorbed hydrogen sulfide substantially exclusively to elemental sulfur; (c) oxidatively regenerating the washing solution from step (b) so as to form a regenerated washing solution; and (d) separating said elemental sulfur from said washing solution.

Claim 2

A method for removing hydrogen sulfide from a hydrogen sulfide-containing gas stream and converting said hydrogen sulfide to elemental sulfur, which comprises: (a) contacting said gas stream with a regenerable quinone-containing washing solution so as to absorb said hydrogen sulfide into said washing solution, the washing solution introduced into contact with said gas stream comprising an aqueous solution having a pH between about 5 and about 10 and containing (1) solubilized vanadium, (2) one or more water-soluble quinones, (3) thiocyanate ions and (4) a water-soluble carboxylate complexing agent, said washing solution having a selected molar ratio of said vanadium to said quinones above about 15, said molar ratio being selected to substantially reduce the formation of contaminant sulfate salts; (b) allowing the absorbed hydrogen sulfide to react with constituents of said washing solution so as to convert said absorbed hydrogen sulfide substantially exclusively to elemental sulfur; (c) oxidatively regenerating the washing solution from step (b) so as to form a regenerated washing solution; and (d) separating said elemental sulfur from said washing solution.

Claim 15

The method defined in any one of claims 1 through 13 wherein said washing solution is substantially free of water-soluble nonquinone aromatic compounds.

Claim 16

A method for removing hydrogen sulfide from a hydrogen sulfide-containing gas stream and converting said hydrogen sulfide to elemental sulfur, which comprises: (a) contacting said gas stream with a regenerable quinone-containing washing solution so as to absorb said hydrogen sulfide into said washing solution, said washing solution comprising an aqueous solution having a pH between about 7 and about 9.5 and containing (1) between about 0.006 and about 0.4 gram-moles of solubilized vanadium per liter, (2) between about 0.001 and about 0.04 gram-moles of one or more water-soluble quinones capable of solubilizing tetravalent vanadium per liter, (3) between about 30 and about 150 grams of thiocyanate ions per liter, and (4) a water-soluble carboxylate complexing agent; said one or more quinones being selected from the group consisting of 1,4-naphthoquinone-2-sulfonate, 1,2-naphthoquinone-4-sulfonate, 1,4-anthraquinone-2-sulfonate, 1,2-anthraquinone-4-sulfonate, the 9,10-anthraquinone-x-sulfonates (wherein x=1 or 2), the x-carboxy-9,10-anthraquinone-y-sulfonates (wherein x=5, 6, 7 or 8 and y=1 or 2), the 9,10-anthraquinone-x,y-disulfonates (wherein x=1 or 2, and y=5, 6, 7 or 8), 1,4-phenanthraquinone-2-sulfonate, 1,2-phenanthraquinone-4-sulfonate, the 9,10-phenanthraquinone-x-sulfonates (wherein x=1 or 2), the 9,10-phenanthraquinone-x,y-disulfonates (wherein x=1 or 2, and y=5, 6, 7 or 8), the water-soluble quinone derivaties thereof, and mixtures thereof, and said washing solution having a molar ratio of said vanadium to said quinones between about 20 and about 70; (b) allowing the absorbed hydrogen sulfide to react with constituents of said washing solution so as to convert said hydrogen sulfide substantially exclusively to elemental sulfur; (c) oxidatively regenerating the washing solution from step (b) so as to form a regenerated washing solution; (d) separating said elemental sulfur from said regenerated washing solution; and (e) recycling the regenerated washing solution from step (d) into contact with said gas stream in step (a).

Claim 17

A method for removing hydrogen sulfide from a hydrogen sulfide-containing gas stream and converting said hydrogen sulfide to elemental sulfur, which comprises: (a) contacting said gas stream with a regenerable quinone-containing washing solution so as to absorb said hydrogen sulfide into said washing solution, said washing solution comprising an aqueous solution having a pH between about 7 and about 9.5 and containing (1) between about 0.006 and about 0.4 gram-moles of solubilized vanadium per liter, (2) between about 0.001 and about 0.04 gram-moles of one or more water-soluble quinones capable of solubilizing tetravalent vanadium per liter, (3) between about 30 and about 150 grams of thiocyanate ions per liter, and (4) a water-soluble carboxylate complexing agent; said one or more quinones being selected from the group consisting of 1,4-naphthoquinone-2-sulfonate, 1,2-naphthoquinone-4-sulfonate, 1,4-anthraquinone-2-sulfonate, 1,2-anthraquinone-4-sulfonate, the 9,10-anthraquinone-x-sulfonates (wherein x=1 or 2), the x-carboxy-9,10-anthraquinone-y-sulfonates (wherein x=5, 6, 7 or 8 and y=1 or 2), the 9,10-anthraquinone-x,y-disulfonates (wherein x=1 or 2, and y=5, 6, 7 or 8), 1,4-phenanthraquinone-2-sulfonate, 1,2-phenanthraquinone-4-sulfonate, the 9,10-phenanthraquinone-x-sulfonates (wherein x=1 or 2), the 9,10-phenanthraquinone-x,y-disulfonates (wherein x=1 or 2, and y=5, 6, 7 or 8), the water-soluble quinone derivaties thereof, and mixtures thereof, and said washing solution having a molar ratio of said vanadium to said quinones between about 20 and about 70; (b) allowing the absorbed hydrogen sulfide to react with constituents of said washing solution so as to convert said hydrogen sulfide substantially exclusively to elemental sulfur; (c) oxidatively regenerating the washing solution from step (b) so as to form a regenerated washing solution; (d) separating said elemental sulfur from said regenerated washing solution; and (e) recycling the regenerated washing solution from step (d) into contact with said gas stream in step (a).

Claim 24

The method defined in any one of claims 15 through 21 wherein said washing solution is substantially free of water-soluble nonquinone aromatic compounds.

Claim 25

A method for removing hydrogen sulfide from a hydrogen sulfide-containing gas stream and converting said hydrogen sulfide to elemental sulfur, which comprises: (a) contacting said gas stream with a regenerable quinone-containing washing solution so as to absorb said hydrogen sulfide into said washing solution, said washing solution comprising an aqueous alkaline solution having a pH between about 7 and about 9.5 and containing (1) between about 0.006 and about 0.4 gram-moles of solubilized vanadium per liter, (2) between about 0.0015 and about 0.015 gram-moles of one or more water-soluble quinones selected from the group consisting of the 9,10-anthraquinone-x,y-disulfonates (wherein x=1 or 2, and y=6 or 7) and the water-soluble quinone derivatives thereof, (3) between about 30 and about 150 grams of thiocyanate ions per liter, (4) a mixture of alkali metal carbonates and alkali metal bicarbonates, and (5) an alkali metal salt of hydroxycarboxylic acid, said washing solutin being substantially free of water-soluble nonquinone aromatic compounds and having a molar ratio of said vanadium to said quinones between about 20 and about 70; (b) allowing the absorbed hydrogen sulfide to react with the constituents of said washing solution so as to convert said hydrogen sulfide substantially exclusively to elemental sulfur; (c) oxidatively regenerating the washing solution from step (b) so as to form a regenerated washing solution; (d) separating said elemental sulfur from said regenerated washing solution; and (e) recycling the regenerated washing solution from step (d) into contact with said gas stream in step (a).

Claim 26

A method for removing hydrogen sulfide from a hydrogen sulfide-containing gas stream and converting said hydrogen sulfide to elemental sulfur, which comprises: (a) contacting said gas stream with a regenerable quinone-containing washing solution so as to absorb said hydrogen sulfide into said washing solution, said washing solution comprising an aqueous alkaline solution having a pH between about 7 and about 9.5 and containing (1) between about 0.006 and about 0.4 gram-moles of solubilized vanadium per liter, (2) between about 0.0015 and about 0.015 gram-moles of one or more water-soluble quinones selected from the group consisting of the 9,10-anthraquinone-x,y-disulfonates (wherein x=1 or 2, and y=6 or 7) and the water-soluble quinone derivatives thereof, (3) between about 30 and about 150 grams of thiocyanate ions per liter, (4) a mixture of alkali metal carbonates and alkali metal bicarbonates, and (5) an alkali metal salt of hydroxycarboxylic acid, said washing solutin being substantially free of water-soluble nonquinone aromatic compounds and having a molar ratio of said vanadium to said quinones between about 20 and about 70; (b) allowing the absorbed hydrogen sulfide to react with the constituents of said washing solution so as to convert said hydrogen sulfide substantially exclusively to elemental sulfur; (c) oxidatively regenerating the washing solution from step (b) so as to form a regenerated washing solution; (d) separating said elemental sulfur from said regenerated washing solution; and (e) recycling the regenerated washing solution from step (d) into contact with said gas stream in step (a).

Claim 30

A method for removing hydrogen sulfide from a hydrogen sulfide-containing gas stream and converting said hydrogen sulfide to elemental sulfur, which comprises: (a) contacting said gas stream with a regenerable quinone-containing washing solution so as to absorb said hydrogen sulfide into said washing solution, said washing solution comprising an aqueous alkaline solution having a pH between about 8 and about 9 and containing (1) between about 0.04 and about 0.16 gram-moles of solubilized vanadium per liter, (2) between about 30 and about 150 grams of thiocyanate ions per liter, (3) a mixture of alkali metal carbonates and alkali metal bicarbonates, (4) an alkali metal citrate, and (5) between about 0.002 and about 0.005 gram-moles per liter of one or more quinones selected from the group consisting of the alkali metal 9,10-anthraquinone-x,y-disulfonates (wherein x=1 or 2, and y=6 or 7), said washing solution being essentially free of water-soluble nonquinone aromatic compounds and having a molar ratio of said vanadium to said quinones between about 20 and about 70; (b) allowing the absorbed hydrogen sulfide to react with the constituents of said washing solution so as to convert said hydrogen sulfide substantially exclusively to elemental sulfur; (c) oxidatively regenerating the washing solution from step (b) so as to form a regenerated washing solution; (d) separating said elemental sulfur from said regenerated washing solution; and (e) recycling the regenerated washing solution from step (d) into contact with said gas stream in step (a).

Claim 31

A method for removing hydrogen sulfide from a hydrogen sulfide-containing gas stream and converting said hydrogen sulfide to elemental sulfur, which comprises: (a) contacting said gas stream with a regenerable quinone-containing washing solution so as to absorb said hydrogen sulfide into said washing solution, said washing solution comprising an aqueous alkaline solution having a pH between about 8 and about 9 and containing (1) between about 0.04 and about 0.16 gram-moles of solubilized vanadium per liter, (2) between about 30 and about 150 grams of thiocyanate ions per liter, (3) a mixture of alkali metal carbonates and alkali metal bicarbonates, (4) an alkali metal citrate, and (5) between about 0.002 and about 0.005 gram-moles per liter of one or more quinones selected from the group consisting of the alkali metal 9,10-anthraquinone-x,y-disulfonates (wherein x=1 or 2, and y=6 or 7), said washing solution being essentially free of water-soluble nonquinone aromatic compounds and having a molar ratio of said vanadium to said quinones between about 20 and about 70; (b) allowing the absorbed hydrogen sulfide to react with the constituents of said washing solution so as to convert said hydrogen sulfide substantially exclusively to elemental sulfur; (c) oxidatively regenerating the washing solution from step (b) so as to form a regenerated washing solution; (d) separating said elemental sulfur from said regenerated washing solution; and (e) recycling the regenerated washing solution from step (d) into contact with said gas stream in step (a).