Patent US3887682A successfully refreshed from Google Patents.
US3887682A
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Process for purifying a gas containing hydrogen sulfide and hydrogen cyanide
Assignee: Tsukishima Kankyo Engineering Ltd
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Filing: 1972-11-02
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Granted: 1975-06-03
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Expires: 1992-11-02
Abstract
Abstract A wet-type desulfurization process is disclosed for purifying gases containing hydrogen sulfide and hydrogen cyanide contaminants. The gas is washed with an alkaline aqueous solution to absorb the contaminants. The wash solution containing the dissolved contaminants is oxidized to form free sulfur from any hydrosulfide salt that might be present. The sulfur is removed as a precipitate. The oxidized wash solution is then roasted to convert the thiocyanates, sulfates, sulfites, and thiosulfates to carbonates, sulfides and hydrosulfides. These salts are then recovered in an aqueous solution, which solution is recycled for use in the absorption or oxidation steps.
Inventors
- 👤 Seiji Kumata
- 👤 Youichi Shimoi
- 👤 Terubika Hirabayashi
- 👤 Yukinori Hiwatashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:58
CPC Classifications
C; C01; C01B; C01B17/00; C01B17/16; C01B17/167; C10; C10K; C10K1/00; C10K1/08; C10K1/10
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
139 words
IN A PROCESS FOR PURIFYING A GAS CONTAINING HYDROGEN SULFIDE AND HYDROGEN CYANIDE IN WHICH SAID GAS IS WASHED WITH AN AQUEOUS ALKALINE SOLUTION TO DISSOLVE THE HYDROGEN SULFIDE AS HYDROSULFIDE AND THE HYDROGEN CYANIDE AS CYANIDE, THE AQUEOUS SOLUTION CONTAINING HYDROSULFIDE AND CYANIDE BEING OXIDIZED TO FORM THIOCYANATES, SULFUR OXIDE SALTS AND A PRECIPITATE OF FREE SULFUR WHICH PRECIPITATE IS THEN REMOVED FROM THE AQUEOUS ALKALINE SOLUTION; THE IMPROVEMENT WHICH COMPRISES: REDUCTIVELY ROASTING THE AQUEOUS ALKALINE SOLUTION CONTAINING THIOCYANATES AND SULFUR OXIDE SALTS IN A COMBUSTION ZONE AT 650*-1100*C AND WITH AN AIR RATIO OF LESS THAN 0.95 TO CONVERT AT LEAST A PORTION OF SAID THIOCYANATES AND SULFUR OXIDE SALTS TO SULFIDES; DISSOLVING SAID SULFIDES TO FORM A THIOCYANATE AND SULFUR OXIDE SALT DEPLETED ALKALINE SOLUTION; AND RECYCLING SAID DEPLETED SOLUTION TO THE ALKLINE AQUEOUS WASH SOLUTION.
Claim 2
Dependent Claim
139 words
IN A PROCESS FOR PURIFYING A GAS CONTAINING HYDROGEN SULFIDE AND HYDROGEN CYANIDE IN WHICH SAID GAS IS WASHED WITH AN AQUEOUS ALKALINE SOLUTION TO DISSOLVE THE HYDROGEN SULFIDE AS HYDROSULFIDE AND THE HYDROGEN CYANIDE AS CYANIDE, THE AQUEOUS SOLUTION CONTAINING HYDROSULFIDE AND CYANIDE BEING OXIDIZED TO FORM THIOCYANATES, SULFUR OXIDE SALTS AND A PRECIPITATE OF FREE SULFUR WHICH PRECIPITATE IS THEN REMOVED FROM THE AQUEOUS ALKALINE SOLUTION; THE IMPROVEMENT WHICH COMPRISES: REDUCTIVELY ROASTING THE AQUEOUS ALKALINE SOLUTION CONTAINING THIOCYANATES AND SULFUR OXIDE SALTS IN A COMBUSTION ZONE AT 650*-1100*C AND WITH AN AIR RATIO OF LESS THAN 0.95 TO CONVERT AT LEAST A PORTION OF SAID THIOCYANATES AND SULFUR OXIDE SALTS TO SULFIDES; DISSOLVING SAID SULFIDES TO FORM A THIOCYANATE AND SULFUR OXIDE SALT DEPLETED ALKALINE SOLUTION; AND RECYCLING SAID DEPLETED SOLUTION TO THE ALKLINE AQUEOUS WASH SOLUTION.
Claim 3
Dependent Claim
139 words
In a process for purifying a gas containing hydrogen sulfide and hydrogen cyanide in which said gas is washed with an aqueous alkaline solution to dissolve the hydrogen sulfide as hydrosulfide and the hydrogen cyanide as cyanide, the aqueous solution containing hydrosulfide and cyanide being oxidized to form thiocyanates, sulfur oxide salts and a precipitate of free sulfur which precipitate is then removed from the aqueous alkaline solution; the improvement which comprises: reductively roasting the aqueous alkaline solution containing thiocyanates and sulfur oxide salts in a combustion zone at 650*-1100*C and with an air ratio of less than 0.95 to convert at least a portion of said thiocyanates and sulfur oxide salts to sulfides; dissolving said sulfides to form a thiocyanate and sulfur oxide salt depleted alkaline solution; and recycling said depleted solution to the alkline aqueous wash solution.
Claim 4
Dependent Claim
139 words
In a process for purifying a gas containing hydrogen sulfide and hydrogen cyanide in which said gas is washed with an aqueous alkaline solution to dissolve the hydrogen sulfide as hydrosulfide and the hydrogen cyanide as cyanide, the aqueous solution containing hydrosulfide and cyanide being oxidized to form thiocyanates, sulfur oxide salts and a precipitate of free sulfur which precipitate is then removed from the aqueous alkaline solution; the improvement which comprises: reductively roasting the aqueous alkaline solution containing thiocyanates and sulfur oxide salts in a combustion zone at 650*-1100*C and with an air ratio of less than 0.95 to convert at least a portion of said thiocyanates and sulfur oxide salts to sulfides; dissolving said sulfides to form a thiocyanate and sulfur oxide salt depleted alkaline solution; and recycling said depleted solution to the alkline aqueous wash solution.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-02 | 1978-12-02 | 1979-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-02 | 1982-12-02 | 1983-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-02 | 1986-12-02 | 1987-06-03 | $7700.00 | Window Closed / Lapsed |