US4004966A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fume control for sulfur dioxide ammonia absorption systems
Assignee: Babcock and Wilcox Co
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Filing: 1974-12-19
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Granted: 1977-01-25
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Expires: 1994-12-19
Abstract
Abstract A method of absorbing SO 2 by use of an absorbing medium containing ammonia compounds is described. In a process wherein sulfur bearing constituents are combusted, SO 2 bearing flue gases are generated. Having been cooled, the flue gases are contacted in a multi-stage absorption system by aqueous absorbents comprised of ammonium compounds which are maintained so that SO 2 is removed from the flue gas and the formation of the ammonium sulfite fume is inhibited.
Inventors
- 👤 Robert E. Matty
- 👤 Stephen S. Strom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 19:03
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/501; D; D21; D21C; D21C11/00; D21C11/06
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
124 words
A fume free method of recovering chemicals useful in forming a digesting cooking liquor from an ammonia base cooking liquor pulping process of cellulosic materials wherein a residual waste liquor is formed comprising: combusting the waste liquor to form a flue gas containing sulfur dioxide; cooling the flue gas; passing the cooled flue gas through a plurality of absorbing zones, while contacting the gas with an aqueous solution of ammonium monosulfite-bisulfite of pH not in excess of 5.9 pH units; adding ammonia to the aqueous solution in each of the said absorbing zones while maintaining the pH of the aqueous solution at no greater than 5.9 pH units; and separating the aqueous solution from the flue gas for use in forming the cooking liquor.
Claim 2
Dependent Claim
124 words
A fume free method of recovering chemicals useful in forming a digesting cooking liquor from an ammonia base cooking liquor pulping process of cellulosic materials wherein a residual waste liquor is formed comprising: combusting the waste liquor to form a flue gas containing sulfur dioxide; cooling the flue gas; passing the cooled flue gas through a plurality of absorbing zones, while contacting the gas with an aqueous solution of ammonium monosulfite-bisulfite of pH not in excess of 5.9 pH units; adding ammonia to the aqueous solution in each of the said absorbing zones while maintaining the pH of the aqueous solution at no greater than 5.9 pH units; and separating the aqueous solution from the flue gas for use in forming the cooking liquor.
Claim 3
Dependent Claim
17 words
A method as in claim 1 wherein the flue gas is accelerated in the said absorbing zones.
Claim 4
Dependent Claim
20 words
A method as in claim 1 wherein the flue gas is cooled to within 30° of its adiabatic saturation temperature.
Claim 5
Dependent Claim
27 words
A method as in claim 1 wherein the aqueous solution of ammonia monosulfite-bisulfite is in the form of a fine spray when contacting in each absorbing zone.
Claim 6
Dependent Claim
17 words
A method as in claim 1 wherein the aqueous solution is processed to form the cooking liquor.
References Cited (Backward Citations)
US2233841A
Cited
US2161055A
Cited
US2676090A
Cited
FR1388690A
Cited
GB1104583A
Cited
US3773472A
Cited
US3843789A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-01-25 | 1980-07-26 | 1981-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-01-25 | 1984-07-26 | 1985-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-01-25 | 1988-07-26 | 1989-01-25 | $7700.00 | Window Closed / Lapsed |