Patent US3607037A successfully refreshed from Google Patents.
US3607037A
Expired / Lapsed
US
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Separation of sulfur dioxide from gases
Assignee: Wellman-Power Gas Inc
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Filing: 1968-12-20
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Granted: 1971-09-21
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Expires: 1988-12-20
Abstract
Abstract Sulfur dioxide is recovered from waste gases by contacting the gas with aqueous sodium, lithium or beryllium sulfite to produce sodium, lithium or beryllium bisulfite and subsequently separating the sulfite to lower the SO2- partial pressure in the bisulfite which can be decomposed to release sulfur dioxide.
Inventors
- 👤 Jack D Terrana
- 👤 Leo A Miller
- 👤 James A Taylor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 14:38
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/501; C; C01; C01B; C01B17/00; C01B17/48; C01B17/50; C01B17/60; C01F; C01F3/00
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
130 words
A process for recovering sulfur dioxide from a sulfur dioxide-containing gas comprising contacting said gas with an aqueous solution of sodium, lithium or beryllium sulfite at a temperature below about 230* F. and sufficient to produce an aqueous solution containing said sulfite and the corresponding bisulfite, crystallizing sulfite from said sulfite and bisulfite-containing solution to increase the sulfur dioxide partial pressure of said bisulfite in solution, the resulting aqueous solution containing greater than about 65 weight percent sodium bisulfite on a dry basis, decomposing said bisulfite of increased sulfur dioxide partial pressure at a temperature of above about 200* F. to about 600* F. and under conditions of temperature, pressure and residence time sufficient to decompose bisulfite to sulfur dioxide, water and the corresponding sulfite, and recovering resulting sulfur dioxide.
Claim 2
Dependent Claim
130 words
A process for recovering sulfur dioxide from a sulfur dioxide-containing gas comprising contacting said gas with an aqueous solution of sodium, lithium or beryllium sulfite at a temperature below about 230* F. and sufficient to produce an aqueous solution containing said sulfite and the corresponding bisulfite, crystallizing sulfite from said sulfite and bisulfite-containing solution to increase the sulfur dioxide partial pressure of said bisulfite in solution, the resulting aqueous solution containing greater than about 65 weight percent sodium bisulfite on a dry basis, decomposing said bisulfite of increased sulfur dioxide partial pressure at a temperature of above about 200* F. to about 600* F. and under conditions of temperature, pressure and residence time sufficient to decompose bisulfite to sulfur dioxide, water and the corresponding sulfite, and recovering resulting sulfur dioxide.
Claim 3
Dependent Claim
12 words
The process of claim 1 in which the sulfite is sodium sulfite.
Claim 4
Dependent Claim
27 words
The process of claim 2 in which the aqueous sodium sulfite solution has a sodium sulfite content greater than about 50 weight percent on a dry basis.
Claim 5
Dependent Claim
19 words
The process of claim 26 in which sulfite crystals obtained by said crystallization are separated from the sulfite-bisulfite solution.
Claim 6
Dependent Claim
12 words
The process of claim 4 in which the sulfite is sodium sulfite.
Claim 7
Dependent Claim
14 words
The process of claim 4 in which said crystallization and decomposing are conducted simultaneously.
Claim 8
Dependent Claim
18 words
The process of claim 6 in which the decomposition is done while removing water from said sulfite-bisulfite solution.
Claim 9
Dependent Claim
12 words
The process of claim 7 in which the sulfite is sodium sulfite.
Claim 10
Dependent Claim
27 words
The process of claim 8 in which the aqueous sodium sulfite solution has a sodium sulfite content greater than about 50 weight percent on a dry basis.
Claim 11
Dependent Claim
28 words
The process of claim 9 including recycling to said gas conTacting an aqueous solution of sodium sulfite prepared by dissolving separated sodium sulfite crystals produced by said crystallization.
Claim 12
Dependent Claim
28 words
The process of claim 5 including recycling to said gas contacting an aqueous solution of sodium sulfite prepared by dissolving separated sodium sulfite crystals produced by said crystallization.
Claim 13
Dependent Claim
20 words
The process of claim 5 wherein said sodium bisulfite is heated to between about 230* and 400* F. during decomposition.
Claim 14
Dependent Claim
25 words
The process of claim 12 wherein the aqueous sodium sulfite solution contacted with said gas is at a temperature from about 90* to 190* F.
Claim 15
Dependent Claim
38 words
The process of claim 13 wherein separated sodium sulfite crystals produced by said crystallization are dissolved in water and recycled to said gas contacting, and the sodium sulfite-sodium bisulfite solution is heated under superatmospheric pressures during said decomposition.
Claim 16
Dependent Claim
23 words
The process of claim 5 wherein said resulting aqueous solution has greater than about 85 weight percent sodium bisulfite on a dry basis.
Claim 17
Dependent Claim
40 words
The process of claim 1 wherein the gas contains sulfur trioxide with or without entrained particulate solids and is preliminarily treated for purifying the gas by removal from the gas of sulfur trioxide with or without said entrained particulate solids.
Claim 18
Dependent Claim
17 words
The process of claim 16 in which the removal is by contact of the gas with water.
Claim 19
Dependent Claim
32 words
The process of claim 17 wherein entrained particulate solids are in the gas and include fly ash, and the contact with water removes both fly ash and sulfur trioxide from the gas.
Claim 20
Dependent Claim
32 words
The process of claim 5 wherein entrained particulate solids are in the gas and include fly ash, and the contact with water removes both fly ash and sulfur trioxide from the gas.
Claim 21
Dependent Claim
118 words
A process for recovering sulfur dioxide from a sulfur dioxide-containing gas comprising contacting said gas with an aqueous solution of sodium sulfite at a temperature below about 190* F. to form sodium bisulfite in said solution, simultaneously decomposing in a decomposition-crystallization zone sodium bisulfite in said solution to sulfur dioxide and water and crystallizing sodium sulfite from said solution at a temperature of above about 200* to about 600* F. while removing water from said solution, removing from said decomposition-crystallization zone sodium sulfite crystal-containing aqueous medium undergoing decomposition while maintaining the dissolved sodium bisulfite content of said solution at greater than about 85 weight percent on a dry basis, and recovering sulfur dioxide resulting from said decomposition-crystallization zone.
Claim 22
Dependent Claim
118 words
A process for recovering sulfur dioxide from a sulfur dioxide-containing gas comprising contacting said gas with an aqueous solution of sodium sulfite at a temperature below about 190* F. to form sodium bisulfite in said solution, simultaneously decomposing in a decomposition-crystallization zone sodium bisulfite in said solution to sulfur dioxide and water and crystallizing sodium sulfite from said solution at a temperature of above about 200* to about 600* F. while removing water from said solution, removing from said decomposition-crystallization zone sodium sulfite crystal-containing aqueous medium undergoing decomposition while maintaining the dissolved sodium bisulfite content of said solution at greater than about 85 weight percent on a dry basis, and recovering sulfur dioxide resulting from said decomposition-crystallization zone.
Claim 23
Dependent Claim
21 words
The process of claim 20 wherein removed sodium sulfite crystals are separated and recycled in aqueous solution to said gas contacting.
Claim 24
Dependent Claim
19 words
The process of claim 21 wherein the decomposition temperature is in the range of about 230* to 400* F.
Claim 25
Dependent Claim
40 words
The process of claim 20 wherein the gas contains sulfur trioxide with or without entrained particulate solids and is preliminarily treated for purifying the gas by removal from the gas of sulfur trioxide with or without said entrained particulate solids.
Claim 26
Dependent Claim
17 words
The process of claim 23 in which the removal is by contact of the gas with water.
Claim 27
Dependent Claim
32 words
The process of claim 24 wherein entrained particulate solids are in the gas and include fly ash, and the contact with water removes both fly ash and sulfur trioxide from the gas.
Claim 28
Dependent Claim
30 words
The process of claim 24 wherein sodium sulfite crystals of said crystal-containing aqueous medium removed from said decomposition-crystallization zone, are separated and recycled in aqueous solution to said gas contacting.
Claim 29
Dependent Claim
19 words
The process of claim 26 wherein the decomposition temperature is in the range of about 230* to 400* F.
Claim 30
Dependent Claim
32 words
The process of claim 27 wherein entrained particulate solids are in the gas and include fly ash, and the contact with water removes both fly ash and sulfur Trioxide from the gas.
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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) | 1974-09-20 | 1975-03-22 | 1975-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-20 | 1979-03-22 | 1979-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-20 | 1983-03-22 | 1983-09-21 | $7700.00 | Window Closed / Lapsed |