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US4325924A
Expired / Lapsed
US
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Urea reduction of NOx in fuel rich combustion effluents
Assignee: Electric Power Research Institute
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Filing: 1977-10-25
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Granted: 1982-04-20
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Expires: 1997-10-25
Abstract
Abstract Method of reducing NOx in fuel rich combustion effluents is provided comprising introducing urea at temperatures in excess of about 1900 DEG F. in the presence of excess fuel, wherein said urea is introduced either as a solid or solution in amounts sufficient to reduce the NOx concentration.
Inventors
- 👤 John K. Arand
- 👤 Lawrence J. Muzio
- 👤 Donald P. Teixeira
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:17
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/54; B01D53/56
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
64 words
A process for selectively reducing nitrogen oxides in a combustion effluent, comprising: contacting with urea a nitrogen oxide containing effluent stream having an equivalence ratio of fuel over oxygen, greater than one wherein said urea is present in an amount of from about 0.5 to 10 moles per mole of nitrogen oxide at a temperature in the range of about 1900° to 3000° F.
Claim 2
Dependent Claim
64 words
A process for selectively reducing nitrogen oxides in a combustion effluent, comprising: contacting with urea a nitrogen oxide containing effluent stream having an equivalence ratio of fuel over oxygen, greater than one wherein said urea is present in an amount of from about 0.5 to 10 moles per mole of nitrogen oxide at a temperature in the range of about 1900° to 3000° F.
Claim 3
Dependent Claim
17 words
A method according to claim 1, wherein an ancillary reducing material is introduced concurrently with said urea.
Claim 4
Dependent Claim
23 words
A method according to claim 1, wherein said urea is present in from about 0.75 to 6 moles per mole of nitrogen oxide.
Claim 5
Dependent Claim
20 words
A method according to claim 3, wherein the equivalence ratio of fuel to oxygen is in the range of 1.05-1.5:1.
Claim 6
Dependent Claim
20 words
A method according to claim 1, wherein said urea is introduced as a fine molten spray into said effluent stream.
Claim 7
Dependent Claim
14 words
A method according to claim 1, wherein said urea is introduced as a solution.
Claim 8
Dependent Claim
11 words
A method according to claim 6, wherein said solution is aqueous.
Claim 9
Dependent Claim
11 words
A method according to claim 6, wherein said solution is alkanolic.
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) | 1985-04-19 | 1985-10-19 | 1986-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-04-19 | 1989-10-19 | 1990-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-04-19 | 1993-10-19 | 1994-04-20 | $7700.00 | Window Closed / Lapsed |