US4138469A
Expired / Lapsed
US
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Process for catalytically treating exhaust gas containing NOx in the presence of ammonia gas
Assignee: Mitsubishi Chemical Corp
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Filing: 1977-03-28
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Granted: 1979-02-06
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Expires: 1997-03-28
Abstract
Abstract A process for treating an exhaust gas containing nitrogen oxides, oxygen and ammonia gas with a catalyst consisting essentially of titanium oxide, copper oxide in an amount of 0.02 to 0.3 mole and molybdenum oxide or tungsten oxide in an amount of 0.01 to 0.5 mole per one mole of the titanium oxide. Because the catalyst exhibits good properties for decomposition of ammonia as well as for decomposition of nitrogen oxides it is possible to avoid secondary pollution due to unreacted ammonia.
Inventors
- 👤 Akira Kato
- 👤 Shimpei Matsuda
- 👤 Shigeo Uno
- 👤 Jinichi Imahashi
- 👤 Yoshihisa Watanabe
- 👤 Makoto Imanari
- 👤 Fumito Nakajima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 03:41
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8621; B01D53/8625; B01D53/8628; B01D53/8634
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
96 words
A process for treating an exhaust gas containing nitrogen oxides, oxygen and ammonia added as a sole reducing agent with a catalyst at an elevated temperature so as to convert the nitrogen oxides and ammonia into nitrogen and water, wherein the catalyst consists essentially of active oxides of titanium, copper and a member selected from the group consisting of molybdenum, tungsten and a combination thereof, an amount of copper oxide being 0.02 to 0.3 mole and an amount of the oxide of the member being 0.01 to 0.5 mole per one mole of titanium oxide, respectively.
Claim 2
Dependent Claim
96 words
A process for treating an exhaust gas containing nitrogen oxides, oxygen and ammonia added as a sole reducing agent with a catalyst at an elevated temperature so as to convert the nitrogen oxides and ammonia into nitrogen and water, wherein the catalyst consists essentially of active oxides of titanium, copper and a member selected from the group consisting of molybdenum, tungsten and a combination thereof, an amount of copper oxide being 0.02 to 0.3 mole and an amount of the oxide of the member being 0.01 to 0.5 mole per one mole of titanium oxide, respectively.
Claim 3
Dependent Claim
22 words
A process for treating an exhaust gas containing nitrogen oxides, oxygen and ammonia according to claim 1, wherein said member is molybdenum.
Claim 4
Dependent Claim
22 words
A process for treating an exhaust gas containing nitrogen oxides, oxygen and ammonia according to claim 1, wherein said member is tungsten.
Claim 5
Dependent Claim
116 words
A process for treating an exhaust gas containing nitrogen oxides, oxygen and ammonia added as a sole reducing agent with a catalyst at an elevated temperature of 250° to 450° C. so as to convert the nitrogen oxides and ammonia into nitrogen and water, wherein the catalyst consists essentially of active oxides of titanium, copper and a member selected from the group consisting of molybdenum, tungsten and a combination thereof, an amount of copper oxide being 0.02 to 0.3 mole and an amount of the oxide of the member being 0.01 to 0.5 mole per one mole of titanium oxide, respectively, and wherein an amount of the ammonia is stoichiometric with respect to the nitrogen oxides.
Claim 6
Dependent Claim
116 words
A process for treating an exhaust gas containing nitrogen oxides, oxygen and ammonia added as a sole reducing agent with a catalyst at an elevated temperature of 250° to 450° C. so as to convert the nitrogen oxides and ammonia into nitrogen and water, wherein the catalyst consists essentially of active oxides of titanium, copper and a member selected from the group consisting of molybdenum, tungsten and a combination thereof, an amount of copper oxide being 0.02 to 0.3 mole and an amount of the oxide of the member being 0.01 to 0.5 mole per one mole of titanium oxide, respectively, and wherein an amount of the ammonia is stoichiometric with respect to the nitrogen oxides.
Claim 7
Dependent Claim
22 words
A process for treating an exhaust gas containing nitrogen oxides, ammonia and oxygen according to claim 4, wherein the member is molybdenum.
Claim 8
Dependent Claim
22 words
A process for treating an exhaust gas containing nitrogen oxides, ammonia and oxygen according to claim 4, wherein the member is tungsten.
Claim 9
Dependent Claim
37 words
A process for treating an exhaust gas containing nitrogen oxides, ammonia and oxygen according to claim 1, wherein the amount of the oxide of the member is 0.02 to 0.3 mole per one mole of titanium oxide.
Claim 10
Dependent Claim
130 words
A process for treating an exhaust gas containing nitrogen oxides, oxygen and ammonia added as a sole reducing agent with a catalyst at an elevated temperature of 250° to 450° C. so as to convert the nitrogen oxides and ammonia into nitrogen and water wherein the exhaust gas to be treated has the following composition: nitrogen oxides: 150-210 ppm ammonia: 150-210 ppm sulfur oxides: 1030-1370 ppm oxygen: 8-11% by volume nitrogen and others: balance said catalyst consisting essentially of active oxides of titanium, copper and a member selected from the group consisting of molybdenum, tungsten and a combination thereof, wherein an amount of copper oxide is 0.02 to 0.3 mole and an amount of the oxide of member is 0.01 to 0.5 mole per one mole of titanium oxide, respectively.
Claim 11
Dependent Claim
130 words
A process for treating an exhaust gas containing nitrogen oxides, oxygen and ammonia added as a sole reducing agent with a catalyst at an elevated temperature of 250° to 450° C. so as to convert the nitrogen oxides and ammonia into nitrogen and water wherein the exhaust gas to be treated has the following composition: nitrogen oxides: 150-210 ppm ammonia: 150-210 ppm sulfur oxides: 1030-1370 ppm oxygen: 8-11% by volume nitrogen and others: balance said catalyst consisting essentially of active oxides of titanium, copper and a member selected from the group consisting of molybdenum, tungsten and a combination thereof, wherein an amount of copper oxide is 0.02 to 0.3 mole and an amount of the oxide of member is 0.01 to 0.5 mole per one mole of titanium oxide, respectively.
Claim 12
Dependent Claim
38 words
A process for treating an exhaust gas containing nitrogen oxides, ammonia and oxygen according to claim 8, wherein the space velocity of the exhaust gas per unit volume of the catalyst is 1,000 to 100,000 h -1 .
Claim 13
Dependent Claim
22 words
A process for treating an exhaust gas containing nitrogen oxides, ammonia and oxygen according to claim 8, wherein the member is molybdenum.
Claim 14
Dependent Claim
22 words
A process for treating an exhaust gas containing nitrogen oxides, ammonia and oxygen according to claim 8, wherein the member is tungsten.
Claim 15
Dependent Claim
33 words
A process for treating an exhaust gas containing nitrogen oxides, oxygen and ammonia according to claim 1, wherein the active titanium oxide has a surface area of at least 20 m 2 /g.
Claim 16
Dependent Claim
22 words
A process according to claim 12, wherein the active titanium oxide has a surface area of at least 40 m 2 /g.
Claim 17
Dependent Claim
37 words
A process for treating an exhaust gas containing nitrogen oxides, oxygen and ammonia according to claim 4, wherein the amount of the oxide of the member is 0.02 to 0.3 mole per one mole of titanium oxide.
Claim 18
Dependent Claim
33 words
A process for treating an exhaust gas containing nitrogen oxides, oxygen and ammonia according to claim 4, wherein the active titanium oxide has a surface area of at least 20 m 2 /g.
Claim 19
Dependent Claim
22 words
A process according to claim 15, wherein the active titanium oxide has a surface area of at least 40 m 2 /g.
Claim 20
Dependent Claim
37 words
A process for treating an exhaust gas containing nitrogen oxides, ammonia and oxygen according to claim 9, wherein the amount of the oxide of the member is 0.02 to 0.3 mole per one mole of titanium oxide.
Claim 21
Dependent Claim
33 words
A process for treating an exhaust gas containing nitrogen oxides, ammonia and oxygen according to claim 9, wherein the active titanium oxide has a surface area of at least 20 m 2 /g.
Claim 22
Dependent Claim
22 words
A process according to claim 18, wherein the active titanium oxide has a surface area of at least 40 m 2 /g.
Claim 23
Dependent Claim
29 words
A process according to claim 9, wherein the space velocity of the exhaust gas per unit volume of the catalyst is 2,000 h -1 to 30,000 h -1 .
Claim 24
Dependent Claim
113 words
A process for reducing nitrogen oxides contained in an exhaust gas in the presence of oxygen which comprises: adding ammonia gas as a sole reducing agent to the exhaust gas in a stoichiometric excess amount to the nitrogen oxides, and contacting the mixed exhaust gas with a catalyst consisting essentially of active titanium oxide, copper oxide and tungsten oxide or molybdenum oxide in a molar ratio of 1:0.02 to 0.3:0.01 to 0.5, at a temperature of 250° to 450° C. and at a space velocity of 1,000 h -1 to 100,000 h -1 , whereby the reducing reaction of nitrogen oxides and the decomposing reaction of unreacted ammonia take place in one step.
Claim 25
Dependent Claim
113 words
A process for reducing nitrogen oxides contained in an exhaust gas in the presence of oxygen which comprises: adding ammonia gas as a sole reducing agent to the exhaust gas in a stoichiometric excess amount to the nitrogen oxides, and contacting the mixed exhaust gas with a catalyst consisting essentially of active titanium oxide, copper oxide and tungsten oxide or molybdenum oxide in a molar ratio of 1:0.02 to 0.3:0.01 to 0.5, at a temperature of 250° to 450° C. and at a space velocity of 1,000 h -1 to 100,000 h -1 , whereby the reducing reaction of nitrogen oxides and the decomposing reaction of unreacted ammonia take place in one step.
Claim 26
Dependent Claim
22 words
A process according to claim 21, wherein the active titanium oxide has a surface area of at least 20 m 2 /g.
Claim 27
Dependent Claim
22 words
A process according to claim 22, wherein the active titanium oxide has a surface area of at least 40 m 2 /g.
Claim 28
Dependent Claim
16 words
A process according to claim 22, wherein the molar ratio is 1:0.02 to 0.3:0.02 to 0.3.
Claim 29
Dependent Claim
19 words
A process according to claim 22, wherein the space velocity is 2,000 h -1 to 30,000 h -1 .
Claim 30
Dependent Claim
168 words
A process for removing nitrogen oxides from an exhaust gas by reduction with ammonia in the presence of oxygen and a catalyst with the attendant decomposition of unreacted ammonia wherein the nitrogen oxides and ammonia are converted to nitrogen and water comprising the step of contacting an exhaust gas containing nitrogen oxides in the presence of oxygen and ammonia, in an amount stoichiometrically excessive to the nitrogen oxides, with a catalyst consisting essentially of active titanium oxide, copper oxide, and at least one member of tungsten oxide or molybdenum oxide, the active oxides of titanium, copper and the member being in a molar ratio of 1:0.02 to 0.3:0.02 to 0.3, respectively, at a temperature of 250° C. to 450° C. and at a space velocity of 2,000 h -1 to 30,000 h -1 , the active titanium oxide having a surface area of at least 20 m 2 /g, whereby the nitrogen oxides and ammonia are converted to nitrogen and water with the attendant decomposition of unreacted ammonia.
Claim 31
Dependent Claim
168 words
A process for removing nitrogen oxides from an exhaust gas by reduction with ammonia in the presence of oxygen and a catalyst with the attendant decomposition of unreacted ammonia wherein the nitrogen oxides and ammonia are converted to nitrogen and water comprising the step of contacting an exhaust gas containing nitrogen oxides in the presence of oxygen and ammonia, in an amount stoichiometrically excessive to the nitrogen oxides, with a catalyst consisting essentially of active titanium oxide, copper oxide, and at least one member of tungsten oxide or molybdenum oxide, the active oxides of titanium, copper and the member being in a molar ratio of 1:0.02 to 0.3:0.02 to 0.3, respectively, at a temperature of 250° C. to 450° C. and at a space velocity of 2,000 h -1 to 30,000 h -1 , the active titanium oxide having a surface area of at least 20 m 2 /g, whereby the nitrogen oxides and ammonia are converted to nitrogen and water with the attendant decomposition of unreacted ammonia.
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) | 1982-02-05 | 1982-08-07 | 1983-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-02-05 | 1986-08-07 | 1987-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-02-05 | 1990-08-07 | 1991-02-06 | $7700.00 | Window Closed / Lapsed |