US3718733A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Catalytic treatment of exhaust gases
Assignee: Boeing North American Inc
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Filing: 1970-02-20
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Granted: 1973-02-27
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Expires: 1990-02-20
Abstract
Abstract Nitrogen oxides are removed from a waste gas by reaction with carbon monoxide in the presence of a wire mesh selected from copper-containing alloys. Where the exhaust gas contains lead species or other impurities which tend to poison the catalyst, the exhaust gas contacts a molten alkali metal carbonate mixture which removes the lead species prior to the gas contacting the catalyst. Other poisonous impurities such as sulfur dioxide are also removed by the carbonate mixture.
Inventors
- 👤 D Gehri
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:31
CPC Classifications
F; F01; F01N; F01N3/00; F01N3/08; F01N3/0807; F01N3/0814; B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/54; B01D53/56; B01D53/64; B01D53/68; B01D53/74; B01D53/86; B01D53/92; B01D53/922; B01D53/925; F01N3/0871; F01N3/0885; F01N2250/00; F01N2250/12
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
13 words
The method of claim 1 wherein said dry catalyst is a metal mesh.
Claim 2
Dependent Claim
22 words
The method of claim 2 wherein said metal mesh is of a copper alloy containing from 5 to 95 weight percent copper.
Claim 3
Dependent Claim
42 words
The method of claim 3 wherein said alloy contains from 25 to 30 weight percent copper, from 60 to 70 weight percent nickel, and optionally contains amounts of iron up to 6.5 weight percent and lesser amounts of silicon, manganese, and carbon.
Claim 4
Dependent Claim
42 words
The method of claim 1 wherein said gas after contact with said dry catalyst in said second stage is directed to a second catalyst in a third stage for effecting the oxidation of both the CO and hydrocarbons present in said gas.
Claim 5
Dependent Claim
35 words
The method of claim 5 wherein after said gas has contacted said dry catalyst sufficient oxygen is added to said gas to effect the oxidation of CO and hydrocarbons present while contacting said second catalyst.
Claim 6
Dependent Claim
19 words
The method of claim 6 wherein both the dry catalyst and the second catalyst are of substantially identical materials.
Claim 7
Dependent Claim
14 words
The method of claim 7 wherein both of said catalysts comprise a metal mesh.
Claim 8
Dependent Claim
22 words
The method of claim 8 wherein said metal mesh is of a copper alloy containing from 5 to 95 weight percent copper.
Claim 9
Dependent Claim
24 words
The method of claim 9 wherein said alloy contains from 5 to 95 weight percent copper and from 5 to 95 weight percent nickel.
Claim 10
Dependent Claim
42 words
The method of claim 10 wherein said alloy contains from 25 to 30 weight percent copper, from 60 to 70 weight percent nickel, and optionally contains amounts of iron up to 6.5 weight percent and lesser amounts of silicon, manganese, and carbon.
Claim 11
Dependent Claim
52 words
The method of claim 1 wherein said gas contains at least five vol. per cent CO2 and wherein said molten salt also containing a solid carbonaceous material substantially wets the surface of said active metal mesh to promote the reaction between nitrogen oxides and carbon monoxide to form nitrogen and carbon dioxide.
Claim 12
Independent Claim
71 words
A method of removing at least nitrogen oxide impurities from CO2-containing waste gases, also containing carbon monoxide including automotive exhaust gas comprising: providing a metal mesh, wetting said mesh with a molten salt mixture containing a ternary mixture of alkali metal carbonates and a solid carbonaceous material and, passing said gas through said wetted mesh to promote the reaction between nitrogen oxides and carbon monoxide to form nitrogen and carbon dioxide.
Claim 13
Dependent Claim
16 words
The method of claim 1 wherein said active demister metal mesh is of a stainless steel.
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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) | 1976-02-27 | 1976-08-28 | 1977-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-27 | 1980-08-28 | 1981-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-27 | 1984-08-28 | 1985-02-27 | $7700.00 | Window Closed / Lapsed |