US3880982A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for removing nitrogen oxides from exhaust gases
Assignee: Individual
•
Filing: 1972-12-26
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Granted: 1975-04-29
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Expires: 1992-12-26
Abstract
Abstract Nitrogen oxides are removed from exhaust gases, particularly from exhaust gases of internal combustion engines or from exhaust gases obtained in the production of nitric acid. To this end, the nitrogen oxides are reduced to nitrogen with the use of a gaseous reductant, in contact with a catalyst and at elevated temperatures. More particularly, the nitrogen oxide-containing gas in admixture with at least stoichiometric proportions, based on the nitrogen content of the gas, of hydrogen and/or carbon monoxide and/or gaseous hydrocarbon reductants, is contacted at temperatures substantially between 150 and 1100*C, with a catalyst comprising a homogeneous mixture of oxides and/or aluminates of copper, nickel and manganese.
Inventors
- 👤 Jurgen Stenzel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:07
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/92; B01D53/94; B01D53/9445; B01D53/945; B01D53/9404; B01D53/9409; B01D53/9413; B01J; B01J23/00; B01J23/70; B01J23/76; B01J23/84; B01J23/889; B01J23/8892; B01D2251/00; B01D2251/20; B01D2251/208; B01D2255/00; B01D2255/20; B01D2255/207; B01D2255/2073; B01D2255/20753; B01D2255/20761; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
116 words
A PROCESS FOR REMOVING NITROGEN OXIDES FROM EXHAUST GASES, BY REDUCING THE NITROGEN OXIDES TO NITROGEN WITH THE USE OF A GASEOUS REDUCTANT, IN CONTACT WITH A CATALYST AND AT ELEVATED TEMPERATURES, WHICH COMPRISES CONTACTING THE NITROGEN OXIDE-CONTAINING GAS IN ADMIXTURE WITH AT LEAST STOICHIOMETRIC PROPORTIONS, BASED ON THE NITROGEN CONTENT OF THE GAS, OF AT LEAST ONE MEMBER SELECTED FROM THE GROUP CONSISTING OG HYDROGEN, CARNON MONOXIDE AND GASEOUS HYDROCARBON REDUCTANTS, AT TEMPERATURES SUBSTANTIALLY BETWEEN 150* AND 1,100*C., WITH A HOMOGENEOUS MIXTURE OF COPPER, NICKEL AND MANGANESE ALUMINATES AS CATALYSTS, ELEMENTS CU, NI, MN BEING IN THE SAID MIXTURES IN ANY DESIRABLE RATIO WITH RESPECT TO EACH OTHER WITHIN THE LIMITS OF 0.1 TO 1.
Claim 2
Dependent Claim
116 words
A PROCESS FOR REMOVING NITROGEN OXIDES FROM EXHAUST GASES, BY REDUCING THE NITROGEN OXIDES TO NITROGEN WITH THE USE OF A GASEOUS REDUCTANT, IN CONTACT WITH A CATALYST AND AT ELEVATED TEMPERATURES, WHICH COMPRISES CONTACTING THE NITROGEN OXIDE-CONTAINING GAS IN ADMIXTURE WITH AT LEAST STOICHIOMETRIC PROPORTIONS, BASED ON THE NITROGEN CONTENT OF THE GAS, OF AT LEAST ONE MEMBER SELECTED FROM THE GROUP CONSISTING OG HYDROGEN, CARNON MONOXIDE AND GASEOUS HYDROCARBON REDUCTANTS, AT TEMPERATURES SUBSTANTIALLY BETWEEN 150* AND 1,100*C., WITH A HOMOGENEOUS MIXTURE OF COPPER, NICKEL AND MANGANESE ALUMINATES AS CATALYSTS, ELEMENTS CU, NI, MN BEING IN THE SAID MIXTURES IN ANY DESIRABLE RATIO WITH RESPECT TO EACH OTHER WITHIN THE LIMITS OF 0.1 TO 1.
Claim 3
Dependent Claim
77 words
The process as claimed in claim 1, wherein combustion engine exhaust gases containing NO, CO, H2O, and N2 and exhaust gas originating from the production of nitric acid and containing NO, O2, CO, H2O and N2 are freed separately from the nitrogen oxides therein. 3. The process as claimed in claim 1, wherein the exhaust gases of internal combustion engines are freed from nitrogen oxides by directly contacting the gases with, or flowing them over, the catalyst.
Claim 4
Dependent Claim
42 words
The process as claimed in claim 1, wherein the exhaust gases obtained in the production of nitric acid are mixed with the gaseous reductant and the resultant mixture is freed from the nitrogen oxides therein by catalytic reduction of the nitrogen oxides.
Claim 5
Dependent Claim
17 words
The process as claimed in claim 4, wherein the hydrocarbon reductant is natural gas, methane or propane.
Claim 6
Dependent Claim
21 words
The process as claimed in claim 1, wherein the nitrogen oxides are catalytically reduced at temperatures substantially between 300* and 850*C.
Claim 7
Dependent Claim
34 words
The process as claimed in claim 1, wherein the nitrogen oxide-containing gas is passed over the catalyst at a volume-space velocity between 10,000 and 30,000 liters of gas per hour per liter of catalyst.
Claim 8
Dependent Claim
23 words
The process as claimed in claim 1, wherein the homogeneous mixture contains the individual elements in a ratio by weight of Cu:Ni:Mn 1:1:1.
Claim 9
Dependent Claim
21 words
The process as claimed in claim 1, wherein the homogeneous mixture of the aluminates of copper, nickel and manganese is pelletized.
Claim 10
Dependent Claim
25 words
The process as claimed in claim 1, wherein the homogeneous mixture of the aluminates of copper, nickel and manganese is deposited on an inert carrier.
Claim 11
Dependent Claim
19 words
The process as claimed in claim 10, wherein the inert carrier is aluminum oxide, spinel, mullite, cordierite or gehlenite.
Claim 12
Dependent Claim
47 words
The process as claimed in claim 10, wherein the carrier-supported catalyst contains the homogeneous mixture of aluminates of copper, nickel and manganese in a proportion substantially between 2 and 40 weight %, all calculated as metal oxides and based on the overall quantity of catalyst and carrier.
Claim 13
Dependent Claim
39 words
The process as claimed in claim 1, wherein the carrier-supported catalyst contains the homogeneous mixture in a proportion between 5 and 15 weight %, all calculated as metal oxides and based on the overall quantity of catalyst and carrier.
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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) | 1978-04-28 | 1978-10-28 | 1979-04-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-28 | 1982-10-28 | 1983-04-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-28 | 1986-10-28 | 1987-04-29 | $7700.00 | Window Closed / Lapsed |