US4377557A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for removal of sulfur oxides from waste gases
Assignee: Environmental Elements Corp
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Filing: 1981-11-23
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Granted: 1983-03-22
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Expires: 2001-11-23
Abstract
Abstract A process for removing sulfur dioxide from waste gas is provided. The gas is first contacted with an alkaline scrubbing liquor consisting essentially of a sorbent salt in which the cation is sodium or potassium, and one of the anions is borate. The clean gas is vented and the sorbent liquor regenerated for recycle by treatment with lime to precipitate insoluble calcium-sulfur compounds for disposal and regenerate the alkalinity of the scrubbing liquor.
Inventors
- 👤 Philip S. Lowell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 03:31
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/501
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
112 words
A method for the removal of sulfur dioxide from industrial waste gas containing same comprising: (a) scrubbing said gas with an aqueous alkaline liquor, consisting essentially of a sorbent salt in which the cation is sodium or potassium and borate is one of the anions, in an amount sufficient to react with substantially all of the sulfur dioxide present in said gas; (b) venting the resultant waste gas and treating the resultant spent liquor with lime in an amount sufficient to regenerate the scrubbing liquor by precipitating insoluble calcium-sulfur containing salts and regenerating the borate ion; and (c) separating the resultant, insoluble waste solids and recycling the sorbent liquor to step (a).
Claim 2
Independent Claim
112 words
A method for the removal of sulfur dioxide from industrial waste gas containing same comprising: (a) scrubbing said gas with an aqueous alkaline liquor, consisting essentially of a sorbent salt in which the cation is sodium or potassium and borate is one of the anions, in an amount sufficient to react with substantially all of the sulfur dioxide present in said gas; (b) venting the resultant waste gas and treating the resultant spent liquor with lime in an amount sufficient to regenerate the scrubbing liquor by precipitating insoluble calcium-sulfur containing salts and regenerating the borate ion; and (c) separating the resultant, insoluble waste solids and recycling the sorbent liquor to step (a).
Claim 3
Dependent Claim
19 words
The method of claim 1 wherein said spent scrubbing liquor from step (a) is recycled to scrubbing step (a).
Claim 4
Dependent Claim
24 words
The method of claim 1 wherein the makeup borate is added in the form of boric acid, sodium tetraborate, sodium borate, or mixtures thereof.
Claim 5
Dependent Claim
10 words
The method of claim 1 wherein the cation is sodium.
Claim 6
Dependent Claim
25 words
The method of claim 1 wherein the makeup salt to provide the circulating sodium ion is sodium carbonate, bicarbonate, hydroxide, sulfate, sulfite, or mixtures thereof.
Claim 7
Dependent Claim
18 words
The method of claim 1 wherein the scrubbing liquor contains between about 0.05 and 2.0 molal borate ion.
Claim 8
Dependent Claim
23 words
The method of claim 1 wherein the regenerated liquor pH is about 12 and the effluent pH from step (a) is about 6.
Claim 9
Independent Claim
130 words
The method for the removal of sulfur dioxide from industrial waste gas containing same comprising: (a) scrubbing said waste gas with an aqueous alkaline slurry, the liquid portion of the slurry consisting essentially of a sorbent salt in which the cation is sodium or potassium and borate is one of the anions, in an amount sufficient to remove substantially all of the sulfur dioxide present in said gas; (b) venting the resultant waste gas and treating the resultant spent slurry with lime in an amount sufficient to regenerate the scrubbing slurry by precipitating insoluble calcium-sulfur containing salts and regenerating the borate ion; and (c) separating waste solids from a portion of the slurry and removing said solids from the process and returning the liquid from said portion to the process.
Claim 10
Independent Claim
130 words
The method for the removal of sulfur dioxide from industrial waste gas containing same comprising: (a) scrubbing said waste gas with an aqueous alkaline slurry, the liquid portion of the slurry consisting essentially of a sorbent salt in which the cation is sodium or potassium and borate is one of the anions, in an amount sufficient to remove substantially all of the sulfur dioxide present in said gas; (b) venting the resultant waste gas and treating the resultant spent slurry with lime in an amount sufficient to regenerate the scrubbing slurry by precipitating insoluble calcium-sulfur containing salts and regenerating the borate ion; and (c) separating waste solids from a portion of the slurry and removing said solids from the process and returning the liquid from said portion to the process.
Claim 11
Dependent Claim
38 words
The method of claim 1 wherein the spent liquor from step (a) is treated with an oxygen-containing gas to oxidize sulfur to the plus six valence state so that the insoluble calcium-sulfur species will be primarily calcium sulfate.
Claim 12
Dependent Claim
38 words
The method of claim 8 wherein the spent slurry from step (a) is treated with an oxygen-containing gas to oxidize sulfur to the plus six valence state so that the insoluble calcium-sulfur species will be primarily calcium sulfate.
Claim 13
Dependent Claim
22 words
The method of claim 8 wherein a quantity of said spend scrubbing liquor from step (a) is recycled to scrubbing step (a).
Claim 14
Dependent Claim
31 words
The method of claim 8 wherein the makeup borate is added to provide the anion of said slurry in the form of boric acid, sodium tetraborate, sodium borate, or mixtures thereof.
Claim 15
Dependent Claim
10 words
The method of claim 8 wherein the cation is sodium.
Claim 16
Dependent Claim
28 words
The method of claim 8 wherein the makeup salt to provide the circulating sodium ion of said slurry is sodium carbonate, bicarbonate, hydroxide, sulfate, sulfite, or mixtures thereof.
Claim 17
Dependent Claim
18 words
The method of claim 8 wherein the scrubbing liquor contains between about 0.05 and 2.0 molal borate ion.
Claim 18
Dependent Claim
28 words
The method of claim 8 wherein the pH of the regenerated liquor from step (c) is about 12 and the effluent pH from step (a) is about 6.
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) | 1986-03-21 | 1986-09-20 | 1987-03-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-03-21 | 1990-09-20 | 1991-03-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-03-21 | 1994-09-20 | 1995-03-22 | $7700.00 | Window Closed / Lapsed |