Sulfur process

Claim 2

A process for the removal of H 2 S from a sour gaseous stream comprising: (a) contacting the sour gaseous stream in a contacting zone with an aqueous reaction solution at a temperature below the melting point of sulfur, the mixture comprising an effective amount of the ferric chelate of nitrilotriacetic acid and a modifying amount of a modifier selected from compounds having the formula C n H 2n-1 OH, wherein n is a whole number from 4 to 22, and mixtures thereof, to produce a sweet gas stream and an aqueous admixture containing crystalline sulfur and a reduced reactant; (b) removing at least a portion of the crystalline sulfur from the aqueous admixture; (c) regenerating the aqueous admixture in a regenerating zone with oxygen to produce a regenerated reactant; and (d) returning aqueous admixture from the regeneration zone to the contacting zone.

Claim 3

The method of claim 1 wherein the stream from which the H 2 S is removed is selected from naturally occurring gases, synthesis gases, process gases, and fuel gases, and wherein the sulfur is removed by filtration.

Claim 4

The method of claim 1 wherein the sour gaseous stream is selected from natural gas, a stream derived from the gasification of coal, or a hydrocarbon stream, and n is a whole number from 4 through 18.

Claim 5

A process for the removal of H 2 S from a sour gaseous stream comprising: (a) contacting the sour gaseous stream in a contacting zone with an aqueous reaction solution at a temperature below the melting point of sulfur, the mixture comprising an effective amount of the ferric chelate of nitrilotriacetic acid and a modifying amount of a modifier selected from compounds having the formula C n H 2n-1 OH, wherein n is a whole number from 4 through 18, and mixtures thereof, to produce a sweet gas stream and an aqueous admixture containing crystalline sulfur and a reduced reactant; (b) regenerating the aqueous admixture in a regeneration zone with oxygen to produce a regenerated reactant; (c) removing at least a portion of the crystalline sulfur from the aqueous admixture; and (d) returning aqueous admixture from step (c) to the contacting zone.

Claim 6

A process for the removal of H 2 S from a sour gaseous stream comprising: (a) contacting the sour gaseous stream in a contacting zone with an aqueous reaction solution at a temperature below the melting point of sulfur, the mixture comprising an effective amount of the ferric chelate of nitrilotriacetic acid and a modifying amount of a modifier selected from compounds having the formula C n H 2n-1 OH, wherein n is a whole number from 4 through 18, and mixtures thereof, to produce a sweet gas stream and an aqueous admixture containing crystalline sulfur and a reduced reactant; (b) regenerating the aqueous admixture in a regeneration zone with oxygen to produce a regenerated reactant; (c) removing at least a portion of the crystalline sulfur from the aqueous admixture; and (d) returning aqueous admixture from step (c) to the contacting zone.

Claim 7

The method of claim 4 wherein the stream from which the H 2 S is removed is selected from naturally occurring gases, synthesis gases, process gases, and fuel gases, and wherein the sulfur is removed by filtration.

Claim 8

The method of claim 4 wherein the sour gaseous stream is selected from natural gas, a stream derived from the gasification of coal, or a hydrocarbon stream, and n is a whole number from 4 through 18.

Claim 9

A process for the removal of H 2 S and CO 2 from a sour gaseous stream comprising: (a) contacting the sour gaseous stream in a contacting zone at a temperature below the melting point of sulfur with a lean CO 2 -selective absorbent mixture containing an effective amount of the Fe(III) chelate of nitrilotriacetic acid and a modifying amount of a modifier selected from compounds having the formula C n H 2n-1 OH, wherein n is a whole number from 4 through 22, and mixtures thereof, and producing a sweet gaseous stream and an absorbent admixture containing absorbed CO 2 , sulfur, and Fe(II) chelate of nitrilotriacetic acid, (b) removing sulfur from the absorbent admixture, and leaving a solution containing absorbed CO 2 and Fe(II) chelate of nitrilotriacetic acid, (c) stripping the solution containing absorbed CO 2 and said Fe(II) chelate, and regenerating Fe(III) chelate of nitrilotriacetic acid in said solution with oxygen, producing a lean CO 2 -selective absorbent solution containing the Fe(III) chelate of nitrilotriacetic acid, and (d) returning lean CO 2 -selective absorbent solution containing Fe(III) chelate of nitrilotriacetic acid to the contacting zone.

Claim 10

A process for the removal of H 2 S and CO 2 from a sour gaseous stream comprising: (a) contacting the sour gaseous stream in a contacting zone at a temperature below the melting point of sulfur with a lean CO 2 -selective absorbent mixture containing an effective amount of the Fe(III) chelate of nitrilotriacetic acid and a modifying amount of a modifier selected from compounds having the formula C n H 2n-1 OH, wherein n is a whole number from 4 through 22, and mixtures thereof, and producing a sweet gaseous stream and an absorbent admixture containing absorbed CO 2 , sulfur, and Fe(II) chelate of nitrilotriacetic acid, (b) removing sulfur from the absorbent admixture, and leaving a solution containing absorbed CO 2 and Fe(II) chelate of nitrilotriacetic acid, (c) stripping the solution containing absorbed CO 2 and said Fe(II) chelate, and regenerating Fe(III) chelate of nitrilotriacetic acid in said solution with oxygen, producing a lean CO 2 -selective absorbent solution containing the Fe(III) chelate of nitrilotriacetic acid, and (d) returning lean CO 2 -selective absorbent solution containing Fe(III) chelate of nitrilotriacetic acid to the contacting zone.

Claim 11

A process for the removal of H 2 S and CO 2 from a sour gaseous stream comprising: (a) contacting the sour gaseous stream in a contacting zone at a temperature below the melting point of sulfur with a lean CO 2 -selective absorbent solution containing an effective amount of the Fe(III) chelate of nitrilotriacetic acid and a modifying amount of a modifier selected from compounds having the formula C n H 2n-1 OH, wherein n is a whole number from 4 through 22, and mixtures thereof, and producing a sweet gaseous stream and an absorbent mixture containing absorbed CO 2 , sulfur, and Fe(II) chelate of nitrilotriacetic acid, (b) stripping the solution containing absorbed CO 2 , sulfur, and said Fe(II) chelate, and then regenerating the Fe(III) chelate of nitrilotriacetic acid in said solution with oxygen, producing a lean CO 2 -selective absorbent solution containing the Fe(III) chelate of nitrilotriacetic acid, and sulfur, (c) removing sulfur from the lean CO 2 -selective absorbent solution containing the sulfur and the Fe(III) chelate of nitrilotriacetic acid, and leaving a lean CO 2 -selective absorbent solution containing the Fe(III) chelate of nitrilotriacetic acid, and (d) returning lean CO 2 -selective absorbent solution containing the Fe(III) chelate of nitrilotriacetic acid to the contacting zone.

Claim 12

A process for the removal of H 2 S and CO 2 from a sour gaseous stream comprising: (a) contacting the sour gaseous stream in a contacting zone at a temperature below the melting point of sulfur with a lean CO 2 -selective absorbent solution containing an effective amount of the Fe(III) chelate of nitrilotriacetic acid and a modifying amount of a modifier selected from compounds having the formula C n H 2n-1 OH, wherein n is a whole number from 4 through 22, and mixtures thereof, and producing a sweet gaseous stream and an absorbent mixture containing absorbed CO 2 , sulfur, and Fe(II) chelate of nitrilotriacetic acid, (b) stripping the solution containing absorbed CO 2 , sulfur, and said Fe(II) chelate, and then regenerating the Fe(III) chelate of nitrilotriacetic acid in said solution with oxygen, producing a lean CO 2 -selective absorbent solution containing the Fe(III) chelate of nitrilotriacetic acid, and sulfur, (c) removing sulfur from the lean CO 2 -selective absorbent solution containing the sulfur and the Fe(III) chelate of nitrilotriacetic acid, and leaving a lean CO 2 -selective absorbent solution containing the Fe(III) chelate of nitrilotriacetic acid, and (d) returning lean CO 2 -selective absorbent solution containing the Fe(III) chelate of nitrilotriacetic acid to the contacting zone.

Claim 13

A process for the removal of H 2 S and CO 2 from a sour gaseous stream comprising: (a) contacting the sour gaseous stream in a contacting zone at a temperature below the melting point of sulfur with a lean CO 2 -selective absorbent mixture containing an effective amount of the Fe(III) chelate of nitrilotriacetic acid and a modifying amount of a modifier selected from compounds having the formula C n H 2n-1 OH, wherein n is a whole number from 4 through 22, and mixtures thereof, and producing a sweet gaseous stream and an absorbent admixture containing absorbed CO 2 , sulfur, and Fe(II) chelate of nitrilotriacetic acid, (b) removing sulfur from the absorbent admixture, and leaving a solution containing absorbed CO 2 and Fe(III) chelate of nitrilotriacetic acid, (c) stripping the solution containing absorbed CO 2 and said Fe(II) chelate and regenerating the Fe(III) chelate of nitrilotriacetic acid in said solution with oxygen, producing a lean CO 2 -selective absorbent solution containing the Fe(III) chelate of nitrilotriacetic acid, and (d) returning the lean CO 2 -selective absorbent solution containing the Fe(III) chelate of nitrilotriacetic acid to the contacting zone.

Claim 14

A process for the removal of H 2 S and CO 2 from a sour gaseous stream comprising: (a) contacting the sour gaseous stream in a contacting zone at a temperature below the melting point of sulfur with a lean CO 2 -selective absorbent mixture containing an effective amount of the Fe(III) chelate of nitrilotriacetic acid and a modifying amount of a modifier selected from compounds having the formula C n H 2n-1 OH, wherein n is a whole number from 4 through 22, and mixtures thereof, and producing a sweet gaseous stream and an absorbent admixture containing absorbed CO 2 , sulfur, and Fe(II) chelate of nitrilotriacetic acid, (b) removing sulfur from the absorbent admixture, and leaving a solution containing absorbed CO 2 and Fe(III) chelate of nitrilotriacetic acid, (c) stripping the solution containing absorbed CO 2 and said Fe(II) chelate and regenerating the Fe(III) chelate of nitrilotriacetic acid in said solution with oxygen, producing a lean CO 2 -selective absorbent solution containing the Fe(III) chelate of nitrilotriacetic acid, and (d) returning the lean CO 2 -selective absorbent solution containing the Fe(III) chelate of nitrilotriacetic acid to the contacting zone.

Claim 15

A process for the removal of H 2 S and CO 2 from a sour gaseous stream comprising: (a) contacting the sour gaseous stream in a contacting zone at a temperature below the melting point of sulfur with a lean CO 2 -selective absorbent solution containing an effective amount of the Fe(III) chelate of nitrilotriacetic acid and a modifying amount of a modifier selected from compounds having the formula C n H 2n-1 OH, wherein n is a whole number from 4 through 22, and mixtures thereof, and producing a sweet gaseous stream and an absorbent mixture containing absorbed CO 2 , sulfur, and the Fe(II) chelate of nitrilotriacetic acid, (b) stripping the solution containing absorbed CO 2 , sulfur and the said Fe(II) chelate and regenerating the Fe(III) chelate of nitrilotriacetic acid in said solution with oxygen, producing a lean CO 2 -selective absorbent solution containing the Fe(III) chelate of nitrilotriacetic acid and sulfur, (c) removing sulfur from the lean CO 2 -selective absorbent solution containing the sulfur and the Fe(III) chelate of nitrilotriacetic acid, and leaving a lean CO 2 -selective absorbent solution containing the Fe(III) chelate of nitrilotriacetic acid, and (d) returning lean CO 2 -selective absorbent solution containing the Fe(III) chelate of nitrilotriacetic acid to the contacting zone.

Claim 16

A process for the removal of H 2 S and CO 2 from a sour gaseous stream comprising: (a) contacting the sour gaseous stream in a contacting zone at a temperature below the melting point of sulfur with a lean CO 2 -selective absorbent solution containing an effective amount of the Fe(III) chelate of nitrilotriacetic acid and a modifying amount of a modifier selected from compounds having the formula C n H 2n-1 OH, wherein n is a whole number from 4 through 22, and mixtures thereof, and producing a sweet gaseous stream and an absorbent mixture containing absorbed CO 2 , sulfur, and the Fe(II) chelate of nitrilotriacetic acid, (b) stripping the solution containing absorbed CO 2 , sulfur and the said Fe(II) chelate and regenerating the Fe(III) chelate of nitrilotriacetic acid in said solution with oxygen, producing a lean CO 2 -selective absorbent solution containing the Fe(III) chelate of nitrilotriacetic acid and sulfur, (c) removing sulfur from the lean CO 2 -selective absorbent solution containing the sulfur and the Fe(III) chelate of nitrilotriacetic acid, and leaving a lean CO 2 -selective absorbent solution containing the Fe(III) chelate of nitrilotriacetic acid, and (d) returning lean CO 2 -selective absorbent solution containing the Fe(III) chelate of nitrilotriacetic acid to the contacting zone.

Claim 17

The process of claim 7 wherein the lean CO 2 -selective absorbent mixture comprises an absorbent selected from diethylene glycol monoethyl ether, propylene carbonate, tetraethylene glycol-dimethylether, N-methyl pyrrolidone, sulfolane, methyl isobutyl ketone, 2,4-pentanedionne, 2,5-hexanedione, diacetone alcohol, hexyl acetate, cyclohexane, mesityl oxide, and 4-methyl-4-methoxy-pentene-2.

Claim 18

The process of claim 8 wherein the lean CO 2 -selective absorbent mixture comprises an absorbent selected from diethylene glycol monoethyl ether, propylene carbonate, tetraethylene glycol-dimethylether, N-methyl pyrrolidone, sulfolane, methyl isobutyl ketone, 2,4-pentanedionne, 2,5-hexanedione, diacetone alcohol, hexyl acetate, cyclohexane, mesityl oxide, and 4-methyl-4-methoxy-pentene-2.

Claim 19

The process of claim 9 wherein the lean CO 2 -selective absorbent mixture comprises an absorbent selected from diethylene glycol monoethyl ether, propylene carbonate, tetraethylene glycol-dimethylether, N-methyl pyrrolidone, sulfolane, methyl isobutyl ketone, 2,4-pentanedionne, 2,5-hexanedione, diacetone alcohol, hexyl acetate, cyclohexane, mesityl oxide, and 4-methyl-4-methoxy-pentene-2.

Claim 20

The process of claim 10 wherein the lean CO 2 -selective absorbent mixture comprises an absorbent selected from diethylene glycol monoethyl ether, propylene carbonate, tetraethylene glycol-dimethylether, N-methyl pyrrolidone, sulfolane, methyl isobutyl ketone, 2,4-pentanedionne, 2,5-hexanedione, diacetone alcohol, hexyl acetate, cyclohexane, mesityl oxide, and 4-methyl-4-methoxy-pentene-2.