US3883639A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of removing sulfur-containing gases from waste gas
Assignee: MW Kellogg Co
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Filing: 1972-12-21
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Granted: 1975-05-13
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Expires: 1992-12-21
Abstract
Abstract This process involves contacting a waste gas containing an oxide of sulfur with an aqueous medium having a pH below 7.1 in an autoregenerative cyclic process using limestone in combination with carbon dioxide, an added amount of a soluble sulfate of a cation such as potassium, lithium, sodium, magnesium or ammonium or mixtures of these compounds to remove the oxides of sulfur. The soluble sulfates may be added directly to the aqueous medium or may be formed in situ from the known carbonate, bicarbonate, oxide, sulfite, bisulfite, or hydroxide of these cations or ammonia after reaction with the sulfur oxides in the waste gas. Sulfur is removed from the cycle in the form of insoluble calcium sulfite and calcium sulfate.
Inventors
- 👤 Jr Walter A Cronkright
- 👤 Bernard G Mandelik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 01:51
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/501; C; C01; C01F; C01F11/00; C01F11/48
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
96 words
A PROCESS FOR REMOVING SULFUR DIOXIDE FROM INDUSTRIAL WASTE GAS WHICH COMPRISES: SCRUBBING WASTE GAS IN A CONTACTING ZONE WITH AN AQUEOUS MEDIUM HAVING A PH BELOW 7.1 CONTAINING CLACIUM CARBONATE, CARBON DIOXIDE AND AT LEAST ABOUT 3 WEIGHT PERCENT OF A SOLUBLE SULFATE SELECTED FROM THE GROUP CONSISTING OF SODIUM, LITHIUM, POTASSIUM, MAGNESIUM, AND AMMONIUM SULFATES, PRECIPITATING SOLIDS SELECTED FROM THE GROUP CONSISTING OF CALCIUM SULFITE AND CALCIUM SULFATE FROM THE AQUEOUS MEDIUM, REMOVING A PORTION OF SAID SOLIDS, AND INTRODUCING A REMAINING PORTION OF THE SOLIDS WITH SAID AQUEOUS MEDIUM TO THE CONTACTING ZONE.
Claim 2
Dependent Claim
96 words
A PROCESS FOR REMOVING SULFUR DIOXIDE FROM INDUSTRIAL WASTE GAS WHICH COMPRISES: SCRUBBING WASTE GAS IN A CONTACTING ZONE WITH AN AQUEOUS MEDIUM HAVING A PH BELOW 7.1 CONTAINING CLACIUM CARBONATE, CARBON DIOXIDE AND AT LEAST ABOUT 3 WEIGHT PERCENT OF A SOLUBLE SULFATE SELECTED FROM THE GROUP CONSISTING OF SODIUM, LITHIUM, POTASSIUM, MAGNESIUM, AND AMMONIUM SULFATES, PRECIPITATING SOLIDS SELECTED FROM THE GROUP CONSISTING OF CALCIUM SULFITE AND CALCIUM SULFATE FROM THE AQUEOUS MEDIUM, REMOVING A PORTION OF SAID SOLIDS, AND INTRODUCING A REMAINING PORTION OF THE SOLIDS WITH SAID AQUEOUS MEDIUM TO THE CONTACTING ZONE.
Claim 3
Dependent Claim
18 words
The process of claim 1 wherein gas-liquid contact time in said contacting zone is less than 3 seconds.
Claim 4
Dependent Claim
13 words
The process of claim 2 wherein said contacting zone is a venturi scrubber.
Claim 5
Dependent Claim
28 words
The process of claim 2 wherein said soluble sulfate in the aqueous medium is present in the range from about 5 weight percent to about 27 weight percent.
Claim 6
Dependent Claim
39 words
The process of claim 1 wherein said soluble sulfate is generated in the aqueous medium by the addition of ammonia or the oxide, hydroxide, carbonate, bicarbonate, sulfite or bisulfite of sodium, lithium, potassium, magnesium or ammonia or mixtures thereof.
Claim 7
Dependent Claim
30 words
The process of claim 4 wherein temperature of the contacting zone is from about 100*F to about 180*F and the pressure is from about 12 psia. to about 18 psia.
Claim 8
Dependent Claim
54 words
The process of claim 1 wherein at least part of the aqueous medium is recovered as an aqueous supernatent containing at least about 3 weight percent of a soluble sulfate selected from the group consisting of sodium, lithium, potassium, magnesium, and ammonium sulfates and said aqueous supernatent is separately introduced to the contacting zone.
Claim 9
Dependent Claim
40 words
The process of claim 4 wherein at least 5 weight percent of the solids introduced to the contacting zone with said aqueous medium are calcium carbonate and said calcium carbonate is added to the aqueous medium as limestone or dolomite.
Claim 10
Dependent Claim
26 words
The process of claim 2 wherein the waste gas contains oxygen, carbon dioxide and from about 0.01 weight percent to about 5 weight percent sulfur dioxide.
Claim 11
Dependent Claim
148 words
A process for removing sulfur dioxide from industrial waste gas which comprises: scrubbing waste gas containing from about 0.01 weight percent to about 5 weight percent sulfur dioxide in a contacting zone wherein gas-liquid contact time is less than 5 seconds with an aqueous medium having a pH below 7.1 containing calcium carbonate, carbon dioxide, and from about 5 weight percent to about 27 weight percent of magnesium sulfate precipitating as solids, calcium sulfite and calcium sulfate from the aqueous medium; removing a portion of said solids; introducing a remaining portion of the solids with said aqueous medium to the contacting zone, said solids containing at least 5 weight percent calcium carbonate based on total solids; recovering at least part of the aqueous medium as an aqueous supernatent containing at least about 5 weight percent of magnesium sulfate; and introducing said aqueous supernatent separately to the contacting zone.
Claim 12
Dependent Claim
148 words
A process for removing sulfur dioxide from industrial waste gas which comprises: scrubbing waste gas containing from about 0.01 weight percent to about 5 weight percent sulfur dioxide in a contacting zone wherein gas-liquid contact time is less than 5 seconds with an aqueous medium having a pH below 7.1 containing calcium carbonate, carbon dioxide, and from about 5 weight percent to about 27 weight percent of magnesium sulfate precipitating as solids, calcium sulfite and calcium sulfate from the aqueous medium; removing a portion of said solids; introducing a remaining portion of the solids with said aqueous medium to the contacting zone, said solids containing at least 5 weight percent calcium carbonate based on total solids; recovering at least part of the aqueous medium as an aqueous supernatent containing at least about 5 weight percent of magnesium sulfate; and introducing said aqueous supernatent separately to the contacting zone.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-12 | 1978-11-11 | 1979-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-12 | 1982-11-11 | 1983-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-12 | 1986-11-11 | 1987-05-13 | $7700.00 | Window Closed / Lapsed |