Sulfur recovery 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 reactant mixture at a temperature below the melting point of sulfur, the mixture comprising an effective amount of an oxidizing polyvalent metal chelate compound and less than 6 percent by weight, based on the weight of the aqueous reactant mixture, of a modifier selected from compounds having the formula C n H 2n+1 OH, wherein n is a number from 4 through 18, and mixtures thereof, and producing 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 mixture; (c) regenerating the aqueous admixture in a regeneration zone with oxygen to produce an aqueous reaction mixture containing a regenerated reactant; (d) returning aqueous reaction mixture from the regeneration zone to the contacting zone.

Claim 3

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

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 12.

Claim 5

The process of claim 3 wherein the reactant is the Fe(III) chelate of nitrilotriacetic acid.

Claim 6

The process of claim 4 wherein the modifier is selected from t-butanol, n-pentanol, n-octanol, n-decanol, n-undecanol, n-dodecanol, and mixtures thereof.

Claim 7

The process of claim 4 wherein the modifier is n-decanol.

Claim 8

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 reactant mixture at a temperature below the melting point of sulfur, the mixture comprising an oxidizing polyvalent metal chelate compound and less than 6 percent by weight, based on the weight of the aqueous reactant mixture, of a modifier selected from compounds having the formula C n H 2n+1 OH, wherein n is a number from 4 through 18, and mixtures thereof, and producing 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 an aqueous reaction mixture containing a regenerated reactant; (c) removing at least a portion of the crystalline sulfur from the aqueous reaction admixture; (d) returning aqueous reaction mixture from step (c) to the contacting zone.

Claim 9

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 reactant mixture at a temperature below the melting point of sulfur, the mixture comprising an oxidizing polyvalent metal chelate compound and less than 6 percent by weight, based on the weight of the aqueous reactant mixture, of a modifier selected from compounds having the formula C n H 2n+1 OH, wherein n is a number from 4 through 18, and mixtures thereof, and producing 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 an aqueous reaction mixture containing a regenerated reactant; (c) removing at least a portion of the crystalline sulfur from the aqueous reaction admixture; (d) returning aqueous reaction mixture from step (c) to the contacting zone.

Claim 10

The method of claim 7 wherein the stream from which the H 2 S and CO 2 are removed is selected from naturally-occurring gases, synthesis gases, process gases and fuel gases.

Claim 11

The method of claim 7 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 12.

Claim 12

The process of claim 9 wherein the reactant is the Fe(III) chelate of nitrilotriacetic acid.

Claim 13

The process of claim 10 wherein the modifier is selected from t-butanol, n-pentanol, n-octanol, n-decanol, n-undecanol, n-dodecanol, and mixtures thereof.

Claim 14

The process of claim 10 wherein the modifier is n-decanol.

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 liquid absorbent mixture containing an effective amount of an oxidizing polyvalent metal chelate compound and less than 6 percent by weight, based on the weight of the lean CO 2 -selective absorbent mixture, of a modifier selected from compounds having the formula C n H 2n+1 OH, wherein n is a number from 4 through 18, and mixtures thereof, and producing a sweet gaseous stream and an absorbent admixture containing absorbed CO 2 , crystalline sulfur, and reduced reactant; (b) removing at least a portion of the crystalline sulfur from the absorbent admixture, and leaving a solution containing absorbed CO 2 and reduced reactant; (c) stripping the solution containing absorbed CO 2 and said reduced reactant to remove CO 2 and regenerating said solution with oxygen to produce a lean CO 2 -selective liquid absorbent mixture containing regenerated reactant, and (d) returning lean CO 2 -selective liquid absorbent mixture containing regenerated reactant 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 liquid absorbent mixture containing an effective amount of an oxidizing polyvalent metal chelate compound and less than 6 percent by weight, based on the weight of the lean CO 2 -selective absorbent mixture, of a modifier selected from compounds having the formula C n H 2n+1 OH, wherein n is a number from 4 through 18, and mixtures thereof, and producing a sweet gaseous stream and an absorbent admixture containing absorbed CO 2 , crystalline sulfur, and reduced reactant; (b) removing at least a portion of the crystalline sulfur from the absorbent admixture, and leaving a solution containing absorbed CO 2 and reduced reactant; (c) stripping the solution containing absorbed CO 2 and said reduced reactant to remove CO 2 and regenerating said solution with oxygen to produce a lean CO 2 -selective liquid absorbent mixture containing regenerated reactant, and (d) returning lean CO 2 -selective liquid absorbent mixture containing regenerated reactant to the contacting zone.

Claim 17

The method of claim 13 wherein the stream from which the H 2 S and CO 2 are removed is selected from naturally-occurring gases, synthesis gases, process gases and fuel gases.

Claim 18

The method of claim 13 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 12.

Claim 19

The process of claim 15 wherein the reactant is the Fe(III) chelate of nitrilotiacetic acid.

Claim 20

The process of claim 16 wherein the modifier is selected from t-butanol, n-pentanol, n-octanol, n-decanol, n-undecanol, n-dodecanol, and mixtures thereof.

Claim 21

The process of claim 16 wherein the modifier is n-decanol.

Claim 22

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 liquid absorbent mixture containing an effective amount of an oxidizing polyvalent metal chelate compound and less than 6 percent by weight, based on the weight of the lean CO 2 -selective absorbent mixture, of a modifier selected from compounds having the formula C n H 2n+1 OH, wherein n is a number from 4 through 18, and mixtures thereof, and producing a sweet gaseous stream and an absorbent mixture containing absorbed CO 2 , crystalline sulfur, and reduced reactant; (b) stripping the solution containing absorbed CO 2 , crystalline sulfur, and said reduced reactant and regenerating said solution with oxygen and producing a lean CO 2 -selective absorbent mixture containing a regenerated reactant and sulfur, (c) removing sulfur from the lean CO 2 -selective absorbent mixture containing the sulfur and the regenerated reactant, and leaving a lean CO 2 -selective liquid absorbent mixture containing regenerated reactant, and (d) returning the CO 2 -selective liquid absorbent mixture containing regenerated reactant to the contacting zone.

Claim 23

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 liquid absorbent mixture containing an effective amount of an oxidizing polyvalent metal chelate compound and less than 6 percent by weight, based on the weight of the lean CO 2 -selective absorbent mixture, of a modifier selected from compounds having the formula C n H 2n+1 OH, wherein n is a number from 4 through 18, and mixtures thereof, and producing a sweet gaseous stream and an absorbent mixture containing absorbed CO 2 , crystalline sulfur, and reduced reactant; (b) stripping the solution containing absorbed CO 2 , crystalline sulfur, and said reduced reactant and regenerating said solution with oxygen and producing a lean CO 2 -selective absorbent mixture containing a regenerated reactant and sulfur, (c) removing sulfur from the lean CO 2 -selective absorbent mixture containing the sulfur and the regenerated reactant, and leaving a lean CO 2 -selective liquid absorbent mixture containing regenerated reactant, and (d) returning the CO 2 -selective liquid absorbent mixture containing regenerated reactant to the contacting zone.

Claim 24

The method of claim 19 wherein the stream from which the H 2 S and CO 2 are removed is selected from naturally-occuring gases, synthesis gases, process gases and fuel gases.

Claim 25

The method of claim 19 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 12.

Claim 26

The process of claim 21 wherein the reactant is the Fe(III) chelate of nitrilotriacetic acid.

Claim 27

The process of claim 22 wherein the modifier is selected from t-butanol, n-pentanol, n-octanol, n-decanol, n-undecanol, n-dodecanol, and mixtures thereof.

Claim 28

The process of claim 22 wherein the modifier is n-decanol.

Claim 29

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 liquid absorbent mixture containing an effective amount of an oxidizing polyvalent metal chelate compound and less than 6 percent by weight, based on the weight of the lean CO 2 -selective absorbent mixture, of a modifier selected from compounds having the formula C n H 2n+1 OH, wherein n is a number from 4 through 18, and mixtures thereof, and producing a sweet gaseous stream and an absorbent admixture containing absorbed CO 2 , crystalline sulfur, and reduced reactant; (b) removing at least a portion of the crystalline sulfur from the absorbent admixture, and leaving a solution containing absorbed CO 2 and reduced reactant; (c) stripping the solution containing absorbed CO 2 and said reduced reactant to remove CO 2 , and then regenerating said solution with oxygen to produce a lean CO 2 -selective liquid absorbent mixture containing regenerated reactant, and (d) returning lean CO 2 -selective liquid absorbent mixture containing regenerated reactant to the contacting zone.

Claim 30

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 liquid absorbent mixture containing an effective amount of an oxidizing polyvalent metal chelate compound and less than 6 percent by weight, based on the weight of the lean CO 2 -selective absorbent mixture, of a modifier selected from compounds having the formula C n H 2n+1 OH, wherein n is a number from 4 through 18, and mixtures thereof, and producing a sweet gaseous stream and an absorbent admixture containing absorbed CO 2 , crystalline sulfur, and reduced reactant; (b) removing at least a portion of the crystalline sulfur from the absorbent admixture, and leaving a solution containing absorbed CO 2 and reduced reactant; (c) stripping the solution containing absorbed CO 2 and said reduced reactant to remove CO 2 , and then regenerating said solution with oxygen to produce a lean CO 2 -selective liquid absorbent mixture containing regenerated reactant, and (d) returning lean CO 2 -selective liquid absorbent mixture containing regenerated reactant to the contacting zone.

Claim 31

The method of claim 25 wherein the stream from which the H 2 S and CO 2 are removed is selected from naturally-occurring gases, synthesis gases, process gases and fuel gases.

Claim 32

The method of claim 25 wherein the sour gaseous stream is a stream derived from the gasification of coal, and n is a whole number from 4 through 12.

Claim 33

The process of claim 26 wherein the reactant is the FE(III) chelate of nitrilotriacetic acid.

Claim 34

The process of claim 28 wherein the modifier is selected from t-butanol, n-pentanol, n-octanol, n-decanol, n-undecanol, n-dodecanol, and mixtures thereof.

Claim 35

The process of claim 29 wherein the modifier is n-decanol.

Claim 36

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 liquid absorbent mixture containing an effective amount of an oxidizing polyvalent metal chelate compound and less than 6 percent by weight, based on the weight of the lean CO 2 -selective absorbent mixture, of a modifier selected from compounds having the formula C n H 2n+1 OH, wherein n is a number from 4 through 18, and mixtures thereof, and producing a sweet gaseous stream and an absorbent mixture containing absorbed CO 2 , crystalline sulfur, and reduced reactant; (b) stripping the solution containing absorbed CO 2 , crystalline sulfur, and said reduced reactant, and then regenerating said solution with oxygen and producing a lean CO 2 -selective absorbent mixture containing a regenerated reactant and sulfur. (c) removing sulfur from the lean CO 2 -selective absorbent mixture containing the sulfur and the regenerated reactant, and leaving a lean CO 2 -selective liquid absorbent mixture containing regenerated reactant, and (d) returning the CO 2 -selective liquid absorbent mixture containing regenerated reactant to the contacting zone.

Claim 37

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 liquid absorbent mixture containing an effective amount of an oxidizing polyvalent metal chelate compound and less than 6 percent by weight, based on the weight of the lean CO 2 -selective absorbent mixture, of a modifier selected from compounds having the formula C n H 2n+1 OH, wherein n is a number from 4 through 18, and mixtures thereof, and producing a sweet gaseous stream and an absorbent mixture containing absorbed CO 2 , crystalline sulfur, and reduced reactant; (b) stripping the solution containing absorbed CO 2 , crystalline sulfur, and said reduced reactant, and then regenerating said solution with oxygen and producing a lean CO 2 -selective absorbent mixture containing a regenerated reactant and sulfur. (c) removing sulfur from the lean CO 2 -selective absorbent mixture containing the sulfur and the regenerated reactant, and leaving a lean CO 2 -selective liquid absorbent mixture containing regenerated reactant, and (d) returning the CO 2 -selective liquid absorbent mixture containing regenerated reactant to the contacting zone.

Claim 38

The method of claim 31 wherein the stream from which the H 2 S and CO 2 are removed is selected from naturally-occurring gases, synthesis gases, process gases and fuel gases.

Claim 39

The method of claim 31 wherein the sour gaseous stream is a stream derived from the gasification of coal, and n is a whole number from 4 through 12.

Claim 40

The process of claim 33 wherein the reactant is the Fe(III) chelate of nitrilotriacetic acid.

Claim 41

The process of claim 34 wherein the modifier is selected from t-butanol, n-pentanol, n-octanol, n-decanol, n-undecanol, n-dodecanol, and mixtures thereof.

Claim 42

The process of claim 35 wherein the modifier is n-decanol.

Claim 43

The process of claims 1 through 12 wherein the modifier is present in an amount of from about 0.01 percent to about 4 percent by weight, based on the weight of the aqueous reactant mixture.

Claim 44

The process of claims 13 through 36 wherein the modifier is present in an amount of from about 0.01 percent to about 4 percent by weight, based on the weight of the CO 2 -selective absorbent mixture.

Claim 45

The process of claims 1 through 12 wherein the modifier is present in an amount of from about 0.01 percent, by weight, based on the weight of the aqueous reactant mixture, to an amount which is at or near the saturation level of the modifier in the reaction solution without forming a significant second phase.