US3632306A
Expired / Lapsed
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Removal of sulfur dioxide from waste gases
Assignee: Chemical Construction Corp
•
Filing: 1969-02-18
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Granted: 1972-01-04
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Expires: 1989-02-18
Abstract
Abstract Waste gases containing sulfur dioxide, which may also contain sulfur trioxide, are scrubbed with an aqueous slurry containing solid reactant particles of an oxide or carbonate of calcium, magnesium or barium, together with an additive containing an acidic radical which solubilizes the calcium, magnesium or barium ion, so that the aqueous slurry absorbs sulfur dioxide from the waste gas. The dissolved sulfur dioxide forms the soluble sulfite radical in solution, which reacts with the dissolved calcium, magnesium or barium ion to precipitate a solid sulfite and regenerate the additive in solution. The solid sulfite or calcium, magnesium or barium is separated from the aqueous liquid phase which is recycled for further scrubbing, together with makeup solid reactant particles. The scrubbed waste gas is discharged to atmosphere.
Inventors
- 👤 John F Villiers-Fisher
- 👤 Abe Warshaw
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 09:22
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/501
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
18 words
The process of claim 1, in which said solid particulate reactant is in the form of powdered limestone.
Claim 2
Dependent Claim
24 words
The process of claim 1, in which said waste gas stream is a flue gas stream generated by the combustion of a sulfur-containing fuel.
Claim 3
Dependent Claim
22 words
The process of claim 1, in which said dissolved acidic radical is derived from a free acid dissolved in said aqueous slurry.
Claim 4
Dependent Claim
24 words
The process of claim 4, in which said free acid is selected from the group consisting of formic acid, acetic acid and propionic acid.
Claim 5
Dependent Claim
22 words
The process of claim 1, in which said dissolved acidic radical is derived from an acidic salt dissolved in said aqueous slurry.
Claim 6
Dependent Claim
22 words
The process of claim 6, in which said acidic salt is selected from the group consisting of ammonium chloride and ammonium nitrate.
Claim 7
Dependent Claim
33 words
The process of claim 1, in which said dissolved acidic radical is present in said aqueous slurry in a proportion in the range of about 0.1 percent to about 5.0 percent by weight.
Claim 8
Dependent Claim
204 words
A process for the removal of sulfur dioxide from a waste gas stream containing sulfur dioxide which comprises scrubbing said waste gas stream with an aqueous slurry containing a solid pArticulate reactant selected from the group consisting of calcium oxide and calcium carbonate, whereby sulfur dioxide is dissolved in said aqueous slurry, said aqueous slurry containing a small but effective amount of dissolved acidic radical, said dissolved acidic radical being the radical of an acid intermediate in strength between carbonic acid and sulfurous acid, whereby the calcium salt of said acidic radical is soluble in said aqueous slurry and calcium ion is dissolved in said aqueous slurry to form the calcium salt of said acidic radical in aqueous solution, agitating the resulting aqueous slurry containing dissolved sulfur dioxide for a time interval, whereby said calcium salt reacts with a soluble compound formed by dissolving of sulfur dioxide into said aqueous slurry, said soluble compound containing a sulfite radical, to form a precipitated solid calcium sulfite and regenerated dissolved acidic radical, separating said solid calcium sulfite from the aqueous liquid phase, adding makeup solid particulate reactant to said aqueous liquid phase, and recycling the resulting aqueous slurry for further scrubbing of said waste gas stream.
Claim 9
Dependent Claim
18 words
The process of claim 9, in which said solid particulate reactant is in the form of powdered limestone.
Claim 10
Dependent Claim
24 words
The process of claim 9, in which said waste gas stream is a flue gas stream generated by the combustion of a sulfur-containing fuel.
Claim 11
Dependent Claim
22 words
The process of claim 9, in which said dissolved acidic radical is derived from a free acid dissolved in said aqueous slurry.
Claim 12
Dependent Claim
24 words
The process of claim 12, in which said free acid is selected from the group consisting of formic acid, acetic acid and propionic acid.
Claim 13
Dependent Claim
22 words
The process of claim 9, in which said dissolved acidic radical is derived from an acidic salt dissolved in said aqueous slurry.
Claim 14
Dependent Claim
22 words
The process of claim 14, in which said acidic salt is selected from the group consisting of ammonium chloride and ammonium nitrate.
Claim 15
Dependent Claim
33 words
The process of claim 9, in which said dissolved acidic radical is present in said aqueous slurry in a proportion in the range of about 0.1 percent to about 5.0 percent by weight.
Claim 16
Dependent Claim
21 words
The process of claim 9, in which said time interval is in the range of about 0.5 minutes to 10 minutes.
Claim 17
Dependent Claim
207 words
A process for the removal of sulfur dioxide from a waste gas stream containing sulfur dioxide which comprises scrubbing said waste gas stream with an aqueous slurry containing a solid particulate reactant selected from the group consisting of calcium oxide and calcium carbonate, said aqueous slurry containing a small but effective amount of dissolved acidic radical, said dissolved acidic radical being the radical of an acid intermediate in strength between carbonic acid and sulfurous acid, whereby the calcium salt of said acidic radical is soluble in said aqueous slurry and calcium ion is dissolved in said aqueous slurry to form the calcium salt of said acidic radical in aqueous solution, said calcium salt reacting with a soluble compound formed by the dissolving of sulfur dioxide into said aqueous slurry, said soluble compound containing a sulfite radical, to form precipitated solid calcium sulfite and regenerated dissolved acidic radical, separating wetted solid particles containing calcium sulfite from the aqueous liquid phase, washing said solid particles with water to remove soluble components containing said acidic radical, adding the resulting wash water to said aqueous liquid phase, adding makeup solid particulate reactant to said aqueous liquid phase, and recycling the resulting aqueous slurry for further scrubbing of said waste gas stream.
Claim 18
Dependent Claim
18 words
The process of claim 18, in which said solid particulate reactant is in the form of powdered limestone.
Claim 19
Dependent Claim
24 words
The process of claim 18, in which said waste gas stream is a flue gas stream generated by the combustion of a sulfur-containing fuel.
Claim 20
Dependent Claim
22 words
The process of claim 18, in which said dissolved acidic radical is derived from a free acid dissolved in said aqueous slurry.
Claim 21
Dependent Claim
24 words
The process of claim 21, in which said free acid is selected from the group consisting of formic acid, acetic acid and propionic acid.
Claim 22
Dependent Claim
22 words
The process of claim 18, in which said dissolved acidic radical is derived from an acidic salt dissolved in said aqueous slurry.
Claim 23
Dependent Claim
22 words
The process of claim 23, in which said acidic salt is selected from the group consisting of ammonium chloride and ammonium nitrate.
Claim 24
Dependent Claim
33 words
The process of claim 18, in which said dissolved acidic radical is present in said aqueous slurry in a proportion in the range of about 0.1 percent to about 5.0 percent by weight.
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) | 1975-01-03 | 1975-07-05 | 1976-01-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-03 | 1979-07-05 | 1980-01-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-03 | 1983-07-05 | 1984-01-04 | $7700.00 | Window Closed / Lapsed |