US4117101A
Expired / Lapsed
US
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Process for reduction of SO2
Assignee: Davy McKee AG
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Filing: 1977-03-14
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Granted: 1978-09-26
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Expires: 1997-03-14
Abstract
Abstract Sulfur dioxide in sulfur dioxide-containing gases is thermally reduced at relatively moderate temperatures under reducing conditions provided by the incomplete combustion of hydrocarbon to produce elemental sulfur. Elemental sulfur can be recovered from the effluent gases from the thermal reduction and the effluent gases may be treated by conventional catalytic processes to recover additional elemental sulfur from the remaining sulfur values.
Inventors
- 👤 Joachim Fechner
- 👤 Siegward Fiebig
- 👤 Friedrich Fischer
- 👤 Herbert Fischer
- 👤 Lars Hellmer
- 👤 Konrad Riedel
- 👤 Adolf Stauffer
- 👤 Kuldip Sud
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 18:46
CPC Classifications
C; C01; C01B; C01B17/00; C01B17/02; C01B17/04; C01B17/0473; C01B17/0478
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
184 words
A process for producing essentially carbon-free elemental sulfur from sulfur dioxide-containing gases having at least about 10 volume percent sulfur dioxide by thermal reduction using relatively moderate temperatures which comprises combusting hydrocarbon, in the essential absence of sulfur dioxide-containing gases, with an oxygen-containing gas, in an insufficient amount on a stoichiometric basis for complete combustion of the hydrocarbon, to provide a thermal reduction zone having reducing conditions including temperatures from about 950° to 1250° C. and pyrolysis of hydrocarbon to provide SO 2 -reducing gas for thermally reducing sulfur dioxide to elemental sulfur; introducing the sulfur dioxide-containing gases into the thermal reduction zone downstream of the hydrocarbon combustion to thermally reduce the sulfur dioxide, with SO 2 -reducing gas, in the relative absence of oxygen, and produce a reaction product containing elemental sulfur and sulfur compounds including carbonyl sulfide or carbon disulfide; catalytically contacting the reaction product under hydrogen sulfide-producing conditions including a temperature of about 200° to 460° C. to convert carbonyl sulfide or carbon disulfide to hydrogen sulfide which can be converted to additional amounts of elemental sulfur; and recovering elemental sulfur.
Claim 2
Dependent Claim
184 words
A process for producing essentially carbon-free elemental sulfur from sulfur dioxide-containing gases having at least about 10 volume percent sulfur dioxide by thermal reduction using relatively moderate temperatures which comprises combusting hydrocarbon, in the essential absence of sulfur dioxide-containing gases, with an oxygen-containing gas, in an insufficient amount on a stoichiometric basis for complete combustion of the hydrocarbon, to provide a thermal reduction zone having reducing conditions including temperatures from about 950° to 1250° C. and pyrolysis of hydrocarbon to provide SO 2 -reducing gas for thermally reducing sulfur dioxide to elemental sulfur; introducing the sulfur dioxide-containing gases into the thermal reduction zone downstream of the hydrocarbon combustion to thermally reduce the sulfur dioxide, with SO 2 -reducing gas, in the relative absence of oxygen, and produce a reaction product containing elemental sulfur and sulfur compounds including carbonyl sulfide or carbon disulfide; catalytically contacting the reaction product under hydrogen sulfide-producing conditions including a temperature of about 200° to 460° C. to convert carbonyl sulfide or carbon disulfide to hydrogen sulfide which can be converted to additional amounts of elemental sulfur; and recovering elemental sulfur.
Claim 3
Dependent Claim
207 words
A process for producing essentially carbon-free elemental sulfur from sulfur dioxide-containing gases having at least about 10 volume percent sulfur dioxide and obtained from the regeneration of an absorbent or adsorbent used in the recovery of SO 2 from gases by thermal reduction using relatively moderate temperatures which comprises combusting hydrocarbon, in the essential absence of sulfur dioxide-containing gases, with an oxygen-containing gas, in an insufficient amount on a stoichiometric basis for complete combustion of the hydrocarbon, to provide a thermal reduction zone having reducing conditions, including temperatures from about 950° to 1250° C. and pyrolysis of hydrocarbon to provide SO 2 -reducing gas, for thermally reducing sulfur dioxide to elemental sulfur; introducing the sulfur dioxide-containing gases into the thermal reduction zone downstream of the hydrocarbon combustion to thermally reduce the sulfur dioxide with SO 2 -reducing gas, in the presence of elemental carbon-inhibiting amounts of water and in the relative absence of oxygen, and produce a reaction product containing elemental sulfur and sulfur compounds; catalytically contacting the reaction product under hydrogen sulfide-producing conditions including a temperature of about 200° to 460° C. to convert carbonyl sulfide or carbon disulfide to hydrogen sulfide which can be converted to additional amounts of elemental sulfur; and recovering elemental sulfur.
Claim 4
Dependent Claim
207 words
A process for producing essentially carbon-free elemental sulfur from sulfur dioxide-containing gases having at least about 10 volume percent sulfur dioxide and obtained from the regeneration of an absorbent or adsorbent used in the recovery of SO 2 from gases by thermal reduction using relatively moderate temperatures which comprises combusting hydrocarbon, in the essential absence of sulfur dioxide-containing gases, with an oxygen-containing gas, in an insufficient amount on a stoichiometric basis for complete combustion of the hydrocarbon, to provide a thermal reduction zone having reducing conditions, including temperatures from about 950° to 1250° C. and pyrolysis of hydrocarbon to provide SO 2 -reducing gas, for thermally reducing sulfur dioxide to elemental sulfur; introducing the sulfur dioxide-containing gases into the thermal reduction zone downstream of the hydrocarbon combustion to thermally reduce the sulfur dioxide with SO 2 -reducing gas, in the presence of elemental carbon-inhibiting amounts of water and in the relative absence of oxygen, and produce a reaction product containing elemental sulfur and sulfur compounds; catalytically contacting the reaction product under hydrogen sulfide-producing conditions including a temperature of about 200° to 460° C. to convert carbonyl sulfide or carbon disulfide to hydrogen sulfide which can be converted to additional amounts of elemental sulfur; and recovering elemental sulfur.
Claim 5
Dependent Claim
39 words
The process of claim 2 wherein the sulfur dioxide containing gases and a portion of the hydrocarbon are introduced into the thermal reduction zone and are contacted with the combustion products of another portion of hydrocarbon and oxygen-containing gas.
Claim 6
Dependent Claim
29 words
The process of claim 3 wherein the hydrocarbon is gaseous hydrocarbon and elemental sulfur is separated from the reaction product before the product is subjected to the catalytic contact.
Claim 7
Dependent Claim
11 words
The process of claim 4 wherein the hydrocarbon is coke-oven gas.
Claim 8
Dependent Claim
22 words
The process of claim 4 wherein the reduction of sulffur dioxide is accelerated by the addition of hydrogen-containing or carbon monoxide-containing gas.
Claim 9
Dependent Claim
32 words
The process of claim 6 wherein the hydrogen-containing or carbon monoxide-containing gas is used in an amount to provide a greater ratio of hydrogen sulfide to sulfur dioxide in the reaction product.
Claim 10
Dependent Claim
17 words
The process of claim 7 wherein town gas is used for the hydrogen-containing or carbon monoxide-containing gas.
Claim 11
Dependent Claim
25 words
The process of claim 4 wherein the thermal reduction of sulfur dioxide is conducted in the presence of less than about 0.2 volume percent oxygen.
Claim 12
Dependent Claim
18 words
The process of claim 9 wherein the sulfur dioxide-containing gases comprise about 5 to 80 volume percent water.
Claim 13
Dependent Claim
27 words
The process of claim 2 wherein the sulfur dioxide-containing gases are evolved from the regeneration of an absorbent or adsorbent employed in a sulfur dioxide recovery unit.
Claim 14
Dependent Claim
68 words
The process of claim 4 wherein the gaseous hydrocarbon is methane; the oxygen-containing gas is air; the reaction product is cooled to condense elemental sulfur which is separated and contains thermally reduced gases comprising sulfur dioxide and hydrogen sulfide; and the thermally reduced gases are contacted with a catalyst at a temperature of about 200° to 460° C. in a separate reaction zone to produce more elemental sulfur.
Claim 15
Dependent Claim
37 words
The process of claim 12 wherein the thermally reduced gases additionally comprise carbonyl sulfide, carbon disulfide, water vapor and hydrogen, and are contacted with hydrogenation and hydrolysis catalyst at 200° to 460° C. to produce hydrogen sulfide.
Claim 16
Dependent Claim
29 words
The process of claim 13 wherein the hydrogenation and hydrolysis catalyst comprises cobalt and molybdenum on bauxite and also catalytically converts sulfur dioxide and hydrogen sulfide to elemental sulfur.
Claim 17
Dependent Claim
31 words
The process of claim 14 wherein the gases after contacting the hydrogenation and hydrolysis catalyst are contacted in at least one separate reaction zone with a catalyst to provide elemental sulfur.
Claim 18
Dependent Claim
36 words
The process of claim 15 wherein after each catalytic reaction zone, the gases are cooled to a temperature in the range of 125° to 160° C. and elemental sulfur is condensed and separated from the gases.
Claim 19
Dependent Claim
19 words
The process of claim 9 wherein the sulfur dioxide-containing gases contain about 20 to 95 volume percent sulfur dioxide.
Claim 20
Dependent Claim
17 words
The process of claim 4 wherein the reducing conditions include temperatures at about 1050° to 1100° C.
Claim 21
Dependent Claim
26 words
The process of claim 4 wherein the oxygen-containing gas provides about 10 to 50 percent of the oxygen required for the complete combustion of total hydrocarbon.
Claim 22
Dependent Claim
198 words
In the process for recovering sulfur dioxide produced by combustion of sulfur-containing carbonaceous materials wherein a sorption agent is regenerated to provide a gaseous stream containing at least 10 vol. % SO 2 sulfur values; the improvement which comprises: oxidizing a gaseous hydrocarbon by incomplete combustion with an oxygen-containing gas, wherein the amount of free oxygen is about 10 to 50% of the stoichiometric amount necessary for total combustion of the hydrocarbon to carbon dioxide and water, thereby providing a hot reducing gas stream containing carbon monoxide, hydrogen, not moe than 0.2 vol. % O 2 , and essentially free of elemental carbon; contacting the SO 2 -containing stream with the reducing gas stream at a reaction temperature of about 950° to 1250° C under thermal reducing conditions to convert SO 2 to a reaction product stream containing elemental sulfur and reduced sulfur compounds; contacting the reaction product stream at about 200° to 460° C with a catalyst to convert the COS and CS 2 to H 2 S; reacting H 2 S with remaining SO 2 to produce elemental sulfur; and recovering substantially all of the sulfur values as pure elemental sulfur substantially free of elemental carbon.
Claim 23
Dependent Claim
198 words
In the process for recovering sulfur dioxide produced by combustion of sulfur-containing carbonaceous materials wherein a sorption agent is regenerated to provide a gaseous stream containing at least 10 vol. % SO 2 sulfur values; the improvement which comprises: oxidizing a gaseous hydrocarbon by incomplete combustion with an oxygen-containing gas, wherein the amount of free oxygen is about 10 to 50% of the stoichiometric amount necessary for total combustion of the hydrocarbon to carbon dioxide and water, thereby providing a hot reducing gas stream containing carbon monoxide, hydrogen, not moe than 0.2 vol. % O 2 , and essentially free of elemental carbon; contacting the SO 2 -containing stream with the reducing gas stream at a reaction temperature of about 950° to 1250° C under thermal reducing conditions to convert SO 2 to a reaction product stream containing elemental sulfur and reduced sulfur compounds; contacting the reaction product stream at about 200° to 460° C with a catalyst to convert the COS and CS 2 to H 2 S; reacting H 2 S with remaining SO 2 to produce elemental sulfur; and recovering substantially all of the sulfur values as pure elemental sulfur substantially free of elemental carbon.
Claim 24
Dependent Claim
21 words
The method of claim 20 wherein the reduced sulfur compounds in the reaction product stream comprise COS and CS 2 .
Claim 25
Dependent Claim
55 words
The method of claim 20 wherein the SO 2 -containing gas contains sufficient water vapor to inhibit free carbon formation; and wherein the reduction of SO 2 is accelerated by addition of H 2 -containing gas or CO-containing gas in amount to provide a ratio of H 2 S to SO 2 for Claus reaction.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-09-25 | 1982-03-27 | 1982-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-09-25 | 1986-03-27 | 1986-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-09-25 | 1990-03-27 | 1990-09-26 | $7700.00 | Window Closed / Lapsed |