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US3932585A
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Method of removing nitrogen oxides from plant exhaust
Assignee: JFE Engineering Corp
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Filing: 1973-09-06
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Granted: 1976-01-13
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Expires: 1993-09-06
Abstract
Abstract A method of removing a nitrogen oxide from an exhaust containing the same which comprises preparing an absorbent solution by adding divalent copper ions alone or a mixture of the divalent copper ions and divalent manganese ions to an acid aqueous solution containing sulfites or acid sulfites of ammonium, alkaline metals, or alkaline earth metals or a mixture of two or more of these compounds; and introducing the plant exhaust into the absorbent solution to carry out reaction between the sulfite radical of the absorbent solution and the nitrogen oxides contained in the exhaust to reduce the nitrogen oxides to nitrogen gas.
Inventors
- 👤 Sanseki Moriguchi
- 👤 Hiroshi Abe
- 👤 Kiyoshi Saito
- 👤 Makoto Miyazawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 07:46
CPC Classifications
A; A44; A44B; A44B19/00; A44B19/24; A44B19/40; A44B19/403; B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/54; B01D53/56
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
160 words
A method of removing a nitrogen oxide from an exhaust gas containing a nitrogen oxide, which comprises: contacting said gas with an acidic aqueous solution consisting essentially of i. a salt selected from the group consisting of ammonium sulfite, ammonium acid sulfite, an alkali metal sulfite, an alkali metal acid sulfite, an alkaline earth metal sulfite, an alkaline earth metal acid sulfite, and a mixture of two or more thereof, ii. at least one copper compound forming divalent copper ions therein, the amount of said copper compound in said solution being such that divalent copper ions are produced in an amount of from 0.01 to 0.1 percent by weight in said solution, and iii. at least one manganese compound forming divalent manganese ions therein, the amount of said manganese compound being such that divalent manganese ions are produced in an amount of from 0.01 to 0.1 percent by weight in said solution, to reduce said nitrogen oxide to nitrogen gas.
Claim 2
Independent Claim
160 words
A method of removing a nitrogen oxide from an exhaust gas containing a nitrogen oxide, which comprises: contacting said gas with an acidic aqueous solution consisting essentially of i. a salt selected from the group consisting of ammonium sulfite, ammonium acid sulfite, an alkali metal sulfite, an alkali metal acid sulfite, an alkaline earth metal sulfite, an alkaline earth metal acid sulfite, and a mixture of two or more thereof, ii. at least one copper compound forming divalent copper ions therein, the amount of said copper compound in said solution being such that divalent copper ions are produced in an amount of from 0.01 to 0.1 percent by weight in said solution, and iii. at least one manganese compound forming divalent manganese ions therein, the amount of said manganese compound being such that divalent manganese ions are produced in an amount of from 0.01 to 0.1 percent by weight in said solution, to reduce said nitrogen oxide to nitrogen gas.
Claim 3
Dependent Claim
34 words
The method of claim 1, wherein the amount of the copper compound is such that divalent copper ions are produced in an amount of from 0.03 to 0.1 percent by weight in said solution.
Claim 4
Dependent Claim
12 words
The method of claim 1, wherein the nitrogen oxide is nitrogen monoxide.
Claim 5
Dependent Claim
12 words
The method of claim 1, wherein the nitrogen oxide is nitrogen dioxide.
Claim 6
Independent Claim
172 words
A method of removing a nitrogen oxide and a sulfur oxide from an exhaust gas containing the same, which comprises: contacting said gas with an acidic aqueous solution having a pH of from 5.8 to 6.5 and consisting essentially of i. a salt selected from the group consisting of ammonium sulfite, ammonium acid sulfite, an alkali metal sulfite, an alkali metal acid sulfite, an alkaline earth metal sulfite, an alkaline earth metal acid sulfite, and a mixture of two or more thereof, ii. at least one copper compound forming divalent copper ions therein, the amount of said copper compound in said solution being such that divalent copper ions are produced in an amount of from 0.01 to 0.1 percent by weight in said solution, and iii. at least one manganese compound forming divalent manganese ions therein, the amount of said manganese compound being such that divalent manganese ions are produced in an amount of from 0.01 to 0.1 percent by weight in said solution, to reduce said nitrogen oxide to nitrogen gas.
Claim 7
Independent Claim
172 words
A method of removing a nitrogen oxide and a sulfur oxide from an exhaust gas containing the same, which comprises: contacting said gas with an acidic aqueous solution having a pH of from 5.8 to 6.5 and consisting essentially of i. a salt selected from the group consisting of ammonium sulfite, ammonium acid sulfite, an alkali metal sulfite, an alkali metal acid sulfite, an alkaline earth metal sulfite, an alkaline earth metal acid sulfite, and a mixture of two or more thereof, ii. at least one copper compound forming divalent copper ions therein, the amount of said copper compound in said solution being such that divalent copper ions are produced in an amount of from 0.01 to 0.1 percent by weight in said solution, and iii. at least one manganese compound forming divalent manganese ions therein, the amount of said manganese compound being such that divalent manganese ions are produced in an amount of from 0.01 to 0.1 percent by weight in said solution, to reduce said nitrogen oxide to nitrogen gas.
Claim 8
Dependent Claim
34 words
The method of claim 5, wherein the amount of the copper compound is such that divalent copper ions are produced in an amount of from 0.03 to 0.1 percent by weight in said solution.
Claim 9
Dependent Claim
12 words
The method of claim 5, wherein the nitrogen oxide is nitrogen monoxide.
Claim 10
Dependent Claim
42 words
The method of claim 7, wherein said gas is contacted with a first said acidic aqueous solution having a pH of less than 6, and is then contacted with a second said acidic aqueous solution having a pH of less than 6.5.
Claim 11
Dependent Claim
12 words
The method of claim 5, wherein the nitrogen oxide is nitrogen dioxide.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-01-12 | 1979-07-14 | 1980-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-12 | 1983-07-14 | 1984-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-12 | 1987-07-14 | 1988-01-13 | $7700.00 | Window Closed / Lapsed |