US5087431A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Catalytic decomposition of cyanuric acid and use of product to reduce nitrogen oxide emissions
Assignee: Cummins Power Generation Inc
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Filing: 1990-09-20
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Granted: 1992-02-11
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Expires: 2010-09-20
Abstract
Abstract A method is described for decomposing cyanuric acid at temperatures of less than about 1000° F., and the method comprises heating the cyanuric acid in the presence of a decomposition catalyst which is effective at below about 1000° F. Examples of useful decomposition catalysts are zirconium, phosphorus and mixtures thereof. Preferably at least some of the zirconium or phosphorus is in the plus four oxidation state. A method also is described for reducing the nitrogen oxide content of gas streams which comprises contacting the gas streams containing nitrogen oxide with an amount of the gaseous decomposition product mixture obtained by decomposing cyanuric acid in the presence of a decomposition catalyst at a temperature of less than about 1000° F.
Inventors
- 👤 Ralph A. Gardner-Chavis
- 👤 Michael P. May
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 14:59
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/54; B01D53/56
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
68 words
A method for reducing the nitrogen oxide content of a gas stream comprising contacting the gas stream with an amount of a gaseous decomposition product mixture obtained by decomposing cyanuric acid in the presence of a catalyst which promotes the decomposition of the cyanuric acid at a temperature of less than about 1000° F., said amount being effective to reduce the nitrogen oxide content of the gas stream.
Claim 2
Independent Claim
68 words
A method for reducing the nitrogen oxide content of a gas stream comprising contacting the gas stream with an amount of a gaseous decomposition product mixture obtained by decomposing cyanuric acid in the presence of a catalyst which promotes the decomposition of the cyanuric acid at a temperature of less than about 1000° F., said amount being effective to reduce the nitrogen oxide content of the gas stream.
Claim 3
Dependent Claim
10 words
The method of claim 1 wherein the catalyst comprises zirconium.
Claim 4
Dependent Claim
10 words
The method of claim 1 wherein the catalyst comprises phosphorus.
Claim 5
Dependent Claim
15 words
The method of claim 1 wherein the catalyst comprises a mixture of zirconium and phosphorus.
Claim 6
Dependent Claim
16 words
The method of claim 1 wherein the catalyst comprises zirconium in the plus four oxidation state.
Claim 7
Dependent Claim
16 words
The method of claim 1 wherein the catalyst comprises phosphorus in the plus four oxidation state.
Claim 8
Dependent Claim
27 words
The method of claim 1 wherein the decomposition catalyst comprises mixtures of zirconium in the plus four oxidation state and phosphorous in the plus four oxidation state.
Claim 9
Dependent Claim
12 words
The method of claim 1 wherein the decomposition catalyst comprises zirconium oxide.
Claim 10
Dependent Claim
23 words
The method of claim 1 wherein the cyanuric acid has been decomposed at a temperature from about 760° F. to about 960° F.
Claim 11
Dependent Claim
26 words
The method of claim 1 wherein the decomposition product is contacted with the gas stream at a temperature of about 300° F. to about 2000° F.
Claim 12
Independent Claim
54 words
A method for reducing the nitrogen oxide content of a gas stream comprising contacting the gas stream with an effective amount of a gaseous decomposition product obtained by decomposing cyanuric acid in the presence of zirconium in the plus four oxidation state at a temperature of from about 760° F. to about 960° F.
Claim 13
Independent Claim
54 words
A method for reducing the nitrogen oxide content of a gas stream comprising contacting the gas stream with an effective amount of a gaseous decomposition product obtained by decomposing cyanuric acid in the presence of zirconium in the plus four oxidation state at a temperature of from about 760° F. to about 960° F.
Claim 14
Dependent Claim
15 words
The method of claim 11 wherein the zirconium is in the plus four oxidation state.
Claim 15
Dependent Claim
13 words
The method of claim 11 wherein the zirconium is present as zirconium oxide.
Claim 16
Dependent Claim
27 words
The method of claim 11 wherein the decomposition product is contacted with the gas stream at a temperature of from about 300° F. to about 2000° F.
Claim 17
Independent Claim
120 words
A method for reducing the nitrogen oxide content of a gas stream comprising (A) decomposing cyanuric acid in a zone by heating the cyanuric acid to a temperature of up to about 1000° F. in the presence of a decomposition catalyst which promotes the decomposition of the cyanuric acid to form a decomposition product mixture; (B) advancing the product mixture from the decomposition zone to a reaction zone containing the gas stream; (C) contacting the decomposition product mixture with the gas stream in the reaction zone for a period of time sufficient to reduce the nitrogen oxide content of the gas stream; and (D) recovering a product gas from the reaction zone which contains a reduced amount of nitrogen oxide.
Claim 18
Independent Claim
120 words
A method for reducing the nitrogen oxide content of a gas stream comprising (A) decomposing cyanuric acid in a zone by heating the cyanuric acid to a temperature of up to about 1000° F. in the presence of a decomposition catalyst which promotes the decomposition of the cyanuric acid to form a decomposition product mixture; (B) advancing the product mixture from the decomposition zone to a reaction zone containing the gas stream; (C) contacting the decomposition product mixture with the gas stream in the reaction zone for a period of time sufficient to reduce the nitrogen oxide content of the gas stream; and (D) recovering a product gas from the reaction zone which contains a reduced amount of nitrogen oxide.
Claim 19
Dependent Claim
10 words
The method of claim 15 wherein the catalyst comprises zirconium.
Claim 20
Dependent Claim
16 words
The method of claim 15 wherein the catalyst comprises zirconium in the plus four oxidation state.
Claim 21
Dependent Claim
10 words
The method of claim 15 wherein the catalyst comprises phosphorus.
Claim 22
Dependent Claim
16 words
The method of claim 15 wherein the catalyst comprises phosphorus in the plus four oxidation state.
Claim 23
Dependent Claim
16 words
The method of claim 15 wherein the decomposition catalyst comprises a mixture of zirconium and phosphorus.
Claim 24
Dependent Claim
24 words
The method of claim 15 wherein the decomposition is effected in (A) at a temperature of from about 760° F. to about 960° F.
Claim 25
Dependent Claim
11 words
The method of claim 15 wherein the catalyst comprises zirconium oxide.
Claim 26
Dependent Claim
17 words
The method of claim 15 wherein solid cyanuric acid is vaporized prior to contact with the catalyst.
Claim 27
Dependent Claim
29 words
The method of claim 15 wherein the decomposition product mixture is contacted with the gas stream in (C) at a temperature from about 300° F. to about 2000° F.
Claim 28
Dependent Claim
15 words
The method of claim 15 wherein the gas stream is an engine exhaust gas stream.
Claim 29
Dependent Claim
20 words
The method of claim 15 wherein the gas stream is a smokestack, boiler exhaust gas stream or gas turbine exhaust.
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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) | 1995-02-10 | 1995-08-12 | 1996-02-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-02-10 | 1999-08-12 | 2000-02-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-02-10 | 2003-08-12 | 2004-02-11 | $7700.00 | Window Closed / Lapsed |