Patent US4732743A successfully refreshed from Google Patents.
US4732743A
Expired / Lapsed
US
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Process for catalytic treatment of exhaust gases
Assignee: Kali Chemie AG
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Filing: 1986-10-24
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Granted: 1988-03-22
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Expires: 2006-10-24
Abstract
Abstract A process and apparatus for removing nitrogen oxides (NO x ) from an exhaust gas by catalytic reduction in the presence of added ammonia in which at temperatures of up to 300° C. the exhaust gas is mixed with the ammonia in such a way that their residence time together before contacting the catalyst is at most one second.
Inventors
- 👤 Torsten Schmidt
- 👤 Robert Walter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 06:03
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8621; B01D53/8625
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
78 words
A process for removing nitrogen oxides (NO x ) from an exhaust gas largely avoiding formation of inactivating deposits on the catalyst comprising the steps of forming a mixture of ammonia and the exhaust gas and contacting the resulting mixture with a reducing catalyst at a temperature from about 150° to 250° C. wherein the time between the formation of the mixture and the occurrence of contact between the mixture and the catalyst is at most 1 second.
Claim 2
Dependent Claim
78 words
A process for removing nitrogen oxides (NO x ) from an exhaust gas largely avoiding formation of inactivating deposits on the catalyst comprising the steps of forming a mixture of ammonia and the exhaust gas and contacting the resulting mixture with a reducing catalyst at a temperature from about 150° to 250° C. wherein the time between the formation of the mixture and the occurrence of contact between the mixture and the catalyst is at most 1 second.
Claim 3
Dependent Claim
29 words
A process according to claim 1, wherein the time between formation of the mixture and the occurrence of contact between themixture and the catalyst is at most 0.2 second.
Claim 4
Dependent Claim
25 words
A process according to claim 1, wherein the process is carried out at an exhaust gas temperature of from about 150° C. to 200° C.
Claim 5
Dependent Claim
22 words
A process according to claim 1, wherein the space velocity of the mixture is from about 5,000 to 20,000 hours -1 .
Claim 6
Dependent Claim
31 words
A process according to claim 1, wherein said reducing catalyst is disposed on a support formed of material selected from the group consisting of SiO 2 , alumosilicate, and mixtures thereof.
Claim 7
Dependent Claim
14 words
A process according to claim 1, wherein said catalyst is a noble metal catalyst.
Claim 8
Dependent Claim
18 words
A process according to claim 6, wherein said noble metal is a noble metal of the platinum group.
Claim 9
Dependent Claim
15 words
A process according to claim 1, wherein said catalyst is a transition metal oxide catalyst.
Claim 10
Dependent Claim
24 words
A process according to claim 8, wherein said transition metal is a transition metal of the fourth period of the periodic table of elements.
Claim 11
Dependent Claim
23 words
A process according to claim 1, wherein said reducing catalyst comprises a support material which is directly coated with a catalytically active component.
Claim 12
Dependent Claim
15 words
A process according to claim 1, wherein said catalyst is formed as a honeycomb material.
Claim 13
Dependent Claim
22 words
A process according to claim 1, wherein said exhaust gas is first passed through a dust separating device before contacting the catalyst.
Claim 14
Dependent Claim
34 words
A process according to claim 1, wherein from 0.5 to 1.5 parts by volume of ammonia are added to the exhaust gas per part by volume of NO x present in the exhaust gas.
Claim 15
Dependent Claim
33 words
A process according to claim 1, wherein less than 1 part by volume of ammonia is added to the exhaust gas per part by volume of NO x present in the exhaust gas.
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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) | 1991-03-22 | 1991-09-21 | 1992-03-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-22 | 1995-09-21 | 1996-03-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-22 | 1999-09-21 | 2000-03-22 | $7700.00 | Window Closed / Lapsed |