US4010238A
Expired / Lapsed
US
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Proces for selective removal of nitrogen oxides from waste gases
Assignee: IMCA CORPORATE VENTURE SERVICE Inc
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Filing: 1974-03-19
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Granted: 1977-03-01
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Expires: 1994-03-19
Abstract
Abstract A process for the selective removal of nitrogen oxides from waste gases containing nitrogen oxides, which comprises contacting the waste gases with a metal oxide catalyst having the following formula: V.sub.x A.sub.y O.sub.z wherein V is vanadium; A is at least one element selected from the group consisting of copper, zinc, tin, lead, titanium, phosphorus, chromium, iron, cobalt and nickel; x and y are each a numeral of 0.5 to 12; and z is a numeral of 1 to 60, at a temperature of 150° to 800° C in the presence of ammonia.
Inventors
- 👤 Tatsuo Shiraishi
- 👤 Shinkichi Shimizu
- 👤 Hiroshi Ichihashi
- 👤 Tadashi Shindo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:40
CPC Classifications
B; B01; B01J; B01J23/00; B01J23/70; B01J23/76; B01J23/84; B01J23/847; B01J23/8472; B01D; B01D53/00; B01D53/34; B01D53/92; B01D53/94; B01D53/9404; B01D53/9409; B01D53/9413; B01D53/9418; B01J23/16; B01J23/20; B01J23/22; B01J23/24; B01J23/26; B01D2251/00; B01D2251/20; B01D2251/206; B01D2251/2062; B01D2255/00; B01D2255/20; B01D2255/207; B01D2255/20707; B01D2255/20723; B01D2255/20738; B01D2255/20746; B01D2255/20753; B01D2255/20761; B01D2255/20784; B01D2255/209; B01D2255/2094
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
106 words
A process for the selective removal of nitrogen oxides from waste gases containing nitrogen oxides, which comprises contacting the waste gases with ammonia in the presence of a metal oxide catalyst for the reduction of nitrogen oxides with ammonia, said catalyst consisting essentially of a composition having the following formula V.sub.x A.sub.y O.sub.z wherein V is vanadium; A is at least one element selected from the group consisting of copper, zinc, tin, lead, titanium, phosphorus, chromium, iron, cobalt and nickel; x and y are each a numeral of 0.5 to 12; and z is determined by the valence requirements of the other elements in said compound.
Claim 2
Dependent Claim
106 words
A process for the selective removal of nitrogen oxides from waste gases containing nitrogen oxides, which comprises contacting the waste gases with ammonia in the presence of a metal oxide catalyst for the reduction of nitrogen oxides with ammonia, said catalyst consisting essentially of a composition having the following formula V.sub.x A.sub.y O.sub.z wherein V is vanadium; A is at least one element selected from the group consisting of copper, zinc, tin, lead, titanium, phosphorus, chromium, iron, cobalt and nickel; x and y are each a numeral of 0.5 to 12; and z is determined by the valence requirements of the other elements in said compound.
Claim 3
Dependent Claim
18 words
The process according to claim 1, wherein A is one or more of copper, tin, chromium and iron.
Claim 4
Dependent Claim
25 words
The process according to claim 1, wherein the ratio of x and y is in the range of 11 : 1 to 3 : 9.
Claim 5
Dependent Claim
26 words
The process according to claim 1, wherein the ammonia is added in an amount of 0.3 to 4 mol to 1 mol of the nitrogen oxides.
Claim 6
Dependent Claim
27 words
The process according to claim 3, wherein the amount of ammonia is in the range of 0.7 to 3 mol to 1 mol of the nitrogen oxides.
Claim 7
Dependent Claim
29 words
The process according to claim 1, wherein the contact of the waste gases with the metal oxide catalyst is carried out at a temperature of 150° to 800° C.
Claim 8
Dependent Claim
18 words
The process according to claim 5, wherein the temperature is in the range of 200° to 400° C.
Claim 9
Dependent Claim
29 words
The process according to claim 1, wherein the waste gases are contacted with the metal oxide catalyst at a space velocity of 2,000 to 100,000 hr - 1 .
Claim 10
Dependent Claim
22 words
The process according to claim 7, wherein the space velocity is in the range of 6,000 to 30,000 hr - 1 .
Claim 11
Dependent Claim
12 words
The process according to claim 1, wherein z is 1 to 60.
Claim 12
Dependent Claim
75 words
The process according to claim 1, wherein V and A are present in the form of oxides or complex oxides in said metal oxide catalyst, said vanadium being penta-, tetra-, or trivalent, said copper being di- or monovalent, said zinc being divalent, said tin or lead being tetra- or divalent, said titanium being tetravalent, said phosphorus being pentavalent, said chromium being hexa-, penta- or trivalent, and said iron, cobalt or nickel being tri- or divalent.
Claim 13
Dependent Claim
103 words
The process according to claim 1, wherein the metal oxide catalyst is prepared by mixing a solution of ammonium metavanadate in water containing monoethanolamine with a solution of a nitrate of copper, zinc, lead, iron, cobalt or nickel; chromic anhydride; titanium tetrachloride; or phosphoric acid in water so as to give a fixed atomic ratio of each metal, penetrating the resulting mixture into an activated alumina having a tablet or granule form, drying the penetrated product at a temperature of 60° to 250° C. until it becomes substantially anhydrous, and then calcining the resultant product at a temperature of 300° to 800° C.
Claim 14
Independent Claim
63 words
A method for the removal of nitrogen oxides from effluent gas which comprises reducing the nitrogen oxides contained within said effluent gas with ammonia in the presence of a catalyst consisting essentially of tin oxide and vanadium oxide in an amount of 20-96 mole percent SnO 2 and 4-80 mole percent V 2 O 5 at a temperature of 250° to 450° C.
Claim 15
Independent Claim
63 words
A method for the removal of nitrogen oxides from effluent gas which comprises reducing the nitrogen oxides contained within said effluent gas with ammonia in the presence of a catalyst consisting essentially of tin oxide and vanadium oxide in an amount of 20-96 mole percent SnO 2 and 4-80 mole percent V 2 O 5 at a temperature of 250° to 450° C.
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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) | 1980-02-29 | 1980-08-30 | 1981-03-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-02-29 | 1984-08-30 | 1985-03-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-02-29 | 1988-08-30 | 1989-03-01 | $7700.00 | Window Closed / Lapsed |