H2 S Removal 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 solution containing an effective amount of a reactant selected from the group consisting of oxidizing polyvalent metal chelate compounds, and mixtures thereof, and a stabilizing amount of a nitrogen-containing composition selected from N,N-diethylhydroxylamine, thiourea, thioemicarbazide, 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 admixture; (c) regenerating the aqueous admixture in a regeneration zone to produce a regenerated reactant; (d) returning aqueous admixture containing regenerated reactant 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 gas.

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.

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 solution containing an effective amount of a reactant selected from the group consisting of oxidizing polyvalent metal chelate compounds and mixtures thereof, and a stabilizing amount of a nitrogen-containing composition selected from N,N-diethylhydroxylamine, thiourea, thiosemicarbazide, 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 to produce an aqueous admixture containing a regenerated reactant; (c) removing at least a portion of the crystalline sulfur from aqueous admixture from step (b) to produce an aqueous admixture having reduced sulfur content; (d) returning aqueous admixture having reduced sulfur content 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 solution containing an effective amount of a reactant selected from the group consisting of oxidizing polyvalent metal chelate compounds and mixtures thereof, and a stabilizing amount of a nitrogen-containing composition selected from N,N-diethylhydroxylamine, thiourea, thiosemicarbazide, 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 to produce an aqueous admixture containing a regenerated reactant; (c) removing at least a portion of the crystalline sulfur from aqueous admixture from step (b) to produce an aqueous admixture having reduced sulfur content; (d) returning aqueous admixture having reduced sulfur content to the contacting zone.

Claim 7

The method of claim 4 having reduced sulfur content wherein the stream from which the H 2 S is removed is selected from naturally-occurring gases, synthesis gases, process gases and fuel gas.

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.

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 a reactant selected from the group consisting of an oxidizing polyvalent metal chelate compounds, and mixtures thereof, and a stabilizing amount of a nitrogen-containing composition selected from N,N-diethylhydroxylamine, thiourea, thiosemicarbazide, 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, producing a lean CO 2 -selective absorbent solution containing regenerated reactant, and (d) returning lean CO 2 -selective absorbent solution containing regenerated reactant 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 a reactant selected from the group consisting of an oxidizing polyvalent metal chelate compounds, and mixtures thereof, and a stabilizing amount of a nitrogen-containing composition selected from N,N-diethylhydroxylamine, thiourea, thiosemicarbazide, 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, producing a lean CO 2 -selective absorbent solution containing regenerated reactant, and (d) returning lean CO 2 -selective absorbent solution containing regenerated reactant 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 mixture containing an effective amount of a reactant selected from the group consisting of oxidizing polyvalent metal chelate compounds, and mixtures thereof, and stabilizing amount of a nitrogen-containing composition selected from N,N-diethylhydroxylamine, thiourea, thiosemicarbazide, and mixtures thereof, and producing a sweet gaseous stream and an adsorbent mixture containing absorbed CO 2 , crystalline sulfur, and reduced reactant; (b) stripping the absorbent mixture containing absorbed CO 2 , crystalline sulfur, and said reduced reactant, and regenerating said absorbent mixture, producing a lean CO 2 -selective absorbent solution containing a regenerated reactant and sulfur, (c) removing at least a portion of the crystalline sulfur from the lean CO 2 -selective absorbent solution containing the sulfur and the regenerated reactant, and leaving a lean CO 2 -selective absorbent solution containing regenerated reactant, and (d) returning lean CO 2 -selective absorbent solution containing regenerated reactant 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 mixture containing an effective amount of a reactant selected from the group consisting of oxidizing polyvalent metal chelate compounds, and mixtures thereof, and stabilizing amount of a nitrogen-containing composition selected from N,N-diethylhydroxylamine, thiourea, thiosemicarbazide, and mixtures thereof, and producing a sweet gaseous stream and an adsorbent mixture containing absorbed CO 2 , crystalline sulfur, and reduced reactant; (b) stripping the absorbent mixture containing absorbed CO 2 , crystalline sulfur, and said reduced reactant, and regenerating said absorbent mixture, producing a lean CO 2 -selective absorbent solution containing a regenerated reactant and sulfur, (c) removing at least a portion of the crystalline sulfur from the lean CO 2 -selective absorbent solution containing the sulfur and the regenerated reactant, and leaving a lean CO 2 -selective absorbent solution containing regenerated reactant, and (d) returning lean CO 2 -selective absorbent solution containing regenerated reactant to the contacting zone,

Claim 13

The process of claim 2 wherein the oxidizing polyvalent metal chelate compound is the Fe(III) chelate of N-(2-hydroxyethyl)ethylenediamine triacetic acid.

Claim 14

The process of claim 2 wherein the oxidizing polyvalent metal chelate compound is the Fe(III) chelate of nitrilotriacetic acid.

Claim 15

The process of claim 3 wherein the oxidizing polyvalent metal chelate compound is the Fe(III) chelate of N-(2-hydroxyethyl)ethylenediamine triacetic acid.

Claim 16

The process of claim 3 wherein the oxidizing polyvalent metal chelate compound is the Fe(III) chelate of nitrilotriacetic acid.

Claim 17

The process of claim 5 wherein the oxidizing polyvalent metal chelate compound is the Fe(III) chelate of N-(2-hydroxyethyl)ethylenediamine triacetic acid.

Claim 18

The process of claim 5 wherein the oxidizing polyvalent metal chelate compound is the Fe(III) chelate of nitrilotriacetic acid.

Claim 19

The process of claim 6 wherein the oxidizing polyvalent metal chelate compound is the Fe(III) chelate of N-(2-hydroxyethyl)ethylenediamine triacetic acid.

Claim 20

The process of claim 6 wherein the oxidizing polyvalent metal chelate compound is the Fe(III) chelate of nitrilotriacetic acid.

Claim 21

The process of claim 7 wherein the oxidizing polyvalent metal chelate compound is the Fe(III) chelate of N-(2-hydroxyethyl)ethylenediamine triacetic acid.

Claim 22

The process of claim 7 wherein the oxidizing polyvalent metal chelate compound is the Fe(III) chelate of nitrilotriacetic acid.

Claim 23

The process of claim 8 wherein the oxidizing polyvalent metal chelate compound is the Fe(III) chelate of N-(2-hydroxyethyl)ethylenediamine triacetic acid.

Claim 24

The process of claim 8 wherein the oxidizing polyvalent metal chelate compound is the Fe(III) chelate of nitrilotriacetic acid.