US3959441A
Expired / Lapsed
US
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Desulfurization process
Assignee: Kobe Steel Ltd
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Filing: 1974-01-07
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Granted: 1976-05-25
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Expires: 1994-01-07
Abstract
Abstract Sulphur dioxide is removed from a stack gas by bringing said gas containing SO 2 into contact with an absorbing solution prepared by adding an hydroxide of a metal from either Groups II, III and VIII of the periodic Table to an aqueous solution of a halide of said metal, wherein the hydroxide is present in an amount of from 0.3 to 0.8 weight percent.
Inventors
- 👤 Isao Furuta
- 👤 Kazuhito Yagaki
- 👤 Toshihiko Masuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:13
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/507
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
75 words
A process for the desulfurization of gases containing sulfur dioxide which comprises the steps of: A. contacting said gases containing sulfur dioxide with an aqueous absorbing solution containing 25-33% by weight alkaline earth metal halide and 0.3 - 0.8% by weight hydroxide of said alkaline earth metal wherein the sulfur dioxide assumes the form of a solid alkaline earth metal sulfite; and B. separating said solid alkaline earth metal sulfite from said aqueous absorbing solution.
Claim 2
Dependent Claim
75 words
A process for the desulfurization of gases containing sulfur dioxide which comprises the steps of: A. contacting said gases containing sulfur dioxide with an aqueous absorbing solution containing 25-33% by weight alkaline earth metal halide and 0.3 - 0.8% by weight hydroxide of said alkaline earth metal wherein the sulfur dioxide assumes the form of a solid alkaline earth metal sulfite; and B. separating said solid alkaline earth metal sulfite from said aqueous absorbing solution.
Claim 3
Dependent Claim
36 words
The desulfurization process of claim 1 wherein the gas containing SO 2 is mixed with oxygen beforehand and then the gas thus mixed is brought into contact with the absorbing solution maintained at 5° to 75°C.
Claim 4
Dependent Claim
27 words
The desulfurization process of claim 1, wherein the absorbing solution is treated with oxygen beforehand, and then brought into contact with the gas containing SO 2 therein.
Claim 5
Dependent Claim
18 words
The desulfurization process of claim 1, wherein said absorbing solution contains from 27.8 to 32.5% by weight halide.
Claim 6
Dependent Claim
19 words
The desulfurization process of claim 1, wherein said halide of a metal is a chloride of calcium or magnesium.
Claim 7
Dependent Claim
15 words
The desulfurization process of claim 5, wherein said halide of a metal is calcium chloride.
Claim 8
Dependent Claim
58 words
The desulfurization process of claim 1, wherein said absorbing solution is circulated through a cleaning tower, thickener and alkali-circulating tank in order, and then the mixture of liquid containing solid matter obtained in said thickener is separated into solid and liquid fractions in a solid liquid separator, while the liquid thus separated is introduced into said alkali-circulating tank.
Claim 9
Dependent Claim
18 words
The desulfurization process of claim 7, wherein the hydroxide of said metal is added to the alkali-circulating tank.
Claim 10
Dependent Claim
24 words
The desulfurization process of claim 7 wherein 0.2 to 0.3 ppm of a high molecular weight anion base flocculant is added into said thickener.
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) | 1979-05-25 | 1979-11-24 | 1980-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-25 | 1983-11-24 | 1984-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-25 | 1987-11-24 | 1988-05-25 | $7700.00 | Window Closed / Lapsed |