Patent US4731231A successfully refreshed from Google Patents.
US4731231A
Expired / Lapsed
US
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NO reduction using sublimation of cyanuric acid
Assignee: Individual
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Filing: 1986-05-05
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Granted: 1988-03-15
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Expires: 2006-05-05
Abstract
Abstract An arrangement for reducing the NO content of a gas stream comprises contacting the gas stream with HNCO at a temperature effective for heat induced decomposition of HNCO and for resultant lowering of the NO content of the gas stream. Preferably, the HNCO is generated by sublimation of cyanuric acid.
Inventors
- 👤 Robert A. Perry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:54
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/54; B01D53/56
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
68 words
A method of reducing the NO content of a gas stream comprising contacting the gas stream with an amount of HNCO at a temperature effective for heat induced decomposition of HNCO, said amount and temperature being effective for resultant lowering of the NO content of the gas stream and said HNCO having been previously generated in gaseous form prior to being conducted into admixture with said gas stream.
Claim 2
Independent Claim
68 words
A method of reducing the NO content of a gas stream comprising contacting the gas stream with an amount of HNCO at a temperature effective for heat induced decomposition of HNCO, said amount and temperature being effective for resultant lowering of the NO content of the gas stream and said HNCO having been previously generated in gaseous form prior to being conducted into admixture with said gas stream.
Claim 3
Dependent Claim
15 words
A method of claim 1, wherein the HNCO is generated by sublimation of cyanuric acid.
Claim 4
Dependent Claim
32 words
A method of claim 1 wherein said HNCO was generated by sublimation of a sublimable source of HNCO and the resultant gaseous HNCO was then conducted into admixture with said gas stream.
Claim 5
Dependent Claim
24 words
A method of claim 2, wherein the sublimation of cyanuric acid is effected at a temperature of about 350° C. to about 800° C.
Claim 6
Dependent Claim
18 words
A method of claim 2, wherein the amount of HNCO is approximately stoichiometric with respect to the NO.
Claim 7
Dependent Claim
15 words
A method of claim 2, wherein the NO-containing gas stream is an effluent gas stream.
Claim 8
Dependent Claim
16 words
A method of claim 6, wherein the effluent gas stream is a vehicle exhaust gas stream.
Claim 9
Dependent Claim
23 words
A method of claim 1, wherein the gas is contacted with HNCO at a temperature of about 400° C. to about 800° C.
Claim 10
Dependent Claim
25 words
A method of claim 2, wherein the sublimable solid is cyanuric acid and it is injected into the gas stream as a hot water solution.
Claim 11
Dependent Claim
25 words
A method of claim 2 wherein said gas stream also comprises NO 2 and the NO 2 content of the gas stream is also lowered.
Claim 12
Independent Claim
117 words
A method of reducing the NO content of a gas stream comprising contacting the gas stream with an amount of HNCO at a temperature effective for heat induced decomposition of HNCO, said amount and temperature being effective for resultant lowering of the NO content of the gas stream, and wherein said contacting is carried out in the presence of a surface which is effective as a catalyst for at least one of the reactions between heat induced decomposition products of HNCO and other components in said gas stream, which reactions lead to lowering of the NO content of the gas stream, or is effective as a catalyst for generating free radicals in the thermal decomposition of HNCO.
Claim 13
Independent Claim
117 words
A method of reducing the NO content of a gas stream comprising contacting the gas stream with an amount of HNCO at a temperature effective for heat induced decomposition of HNCO, said amount and temperature being effective for resultant lowering of the NO content of the gas stream, and wherein said contacting is carried out in the presence of a surface which is effective as a catalyst for at least one of the reactions between heat induced decomposition products of HNCO and other components in said gas stream, which reactions lead to lowering of the NO content of the gas stream, or is effective as a catalyst for generating free radicals in the thermal decomposition of HNCO.
Claim 14
Dependent Claim
10 words
A method of claim 11, wherein said surface comprises iron.
Claim 15
Dependent Claim
24 words
A method of claim 11 wherein said surface contains a metal which is iron, a noble metal, nickel, cobalt, chromium, manganese, vanadium or titanium.
Claim 16
Dependent Claim
18 words
A method of claim 13 wherein said catalytic surface is in the shape of pellets, beads or granules.
Claim 17
Dependent Claim
20 words
A method of claim 11 wherein said catalyst is effective for generating free radicals in the thermal decomposition of HNCO.
Claim 18
Dependent Claim
29 words
A method of claim 15 wherein said contacting is carried out at a temperature lower than that necessary to effect said thermal decomposition in the absence of said catalyst.
Claim 19
Dependent Claim
15 words
A method of claim 11, wherein the HNCO is generated by sublimation of cyanuric acid.
Claim 20
Independent Claim
75 words
A method of reducing the NO content of a gas stream comprising contacting the gas stream with an amount of HNCO at a temperature effective for heat induced decomposition of HNCO, said amount and temperature being effective for resultant lowering of the NO content of the gas stream, and said HNCO being added to said gas stream as a solution of a sublimable solid in a solvent therefor, said sublimable solid producing HNCO upon sublimation.
Claim 21
Independent Claim
75 words
A method of reducing the NO content of a gas stream comprising contacting the gas stream with an amount of HNCO at a temperature effective for heat induced decomposition of HNCO, said amount and temperature being effective for resultant lowering of the NO content of the gas stream, and said HNCO being added to said gas stream as a solution of a sublimable solid in a solvent therefor, said sublimable solid producing HNCO upon sublimation.
Claim 22
Dependent Claim
15 words
A method of claim 18, wherein the HNCO is generated by sublimation of cyanuric acid.
Claim 23
Dependent Claim
18 words
A method of claim 18, wherein the sublimable solid is injected into said gas stream by stream injection.
Claim 24
Independent Claim
68 words
A method of reducing the NO content of a gas stream comprising contacting the gas stream with an amount of HNCO at a temperature effective for heat induced decomposition of HNCO, said amount and temperature being effective for resultant lowering of the NO content of the gas stream, and wherein the HNCO is generated by sublimation of a solid other than cyanuric acid which produces HNCO upon sublimation.
Claim 25
Independent Claim
68 words
A method of reducing the NO content of a gas stream comprising contacting the gas stream with an amount of HNCO at a temperature effective for heat induced decomposition of HNCO, said amount and temperature being effective for resultant lowering of the NO content of the gas stream, and wherein the HNCO is generated by sublimation of a solid other than cyanuric acid which produces HNCO upon sublimation.
Claim 26
Dependent Claim
31 words
A method of claim 21, wherein the HNCO is generated by sublimation of a sublimable substituted derivative of cyanuric acid which produces the HNCO upon sublimation, or by sublimation of cyamelide.
Claim 27
Dependent Claim
45 words
A method of claim 22 wherein said derivative has the structure of cyanuric acid wherein 1-3 of its OH groups are replaced by Cl, Br, F, I, NH 2 , C 1-4 -alkyl, NH--C 1-4 -alkyl, N--(C 1-4 -alkyl)(C 1-4 -alkyl) or a combination thereof.
Claim 28
Independent Claim
62 words
A method of reducing the NO content of a gas stream comprising contacting the gas stream with an amount of HNCO at a temperature effective for heat induced decomposition of HNCO, said amount and temperature being effective for resultant lowering of the NO content of the gas stream, and wherein the temperature of the gas stream is less than about 800° C.
Claim 29
Independent Claim
62 words
A method of reducing the NO content of a gas stream comprising contacting the gas stream with an amount of HNCO at a temperature effective for heat induced decomposition of HNCO, said amount and temperature being effective for resultant lowering of the NO content of the gas stream, and wherein the temperature of the gas stream is less than about 800° C.
Claim 30
Dependent Claim
17 words
A method of claim 24 with the proviso that said gas stream temperature is not 600° C.
Claim 31
Dependent Claim
19 words
A method of claim 25 wherein said gas stream temperature is about 400° to less than about 800° C.
Claim 32
Dependent Claim
15 words
A method of claim 25, wherein the HNCO is generated by sublimation of cyanuric acid.
References Cited (Backward Citations)
JPS5428771A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-03-15 | 1991-09-14 | 1992-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-15 | 1995-09-14 | 1996-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-15 | 1999-09-14 | 2000-03-15 | $7700.00 | Window Closed / Lapsed |