US4208386A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Urea reduction of NOx in combustion effluents
Assignee: Electric Power Research Institute
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Filing: 1976-03-03
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Granted: 1980-06-17
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Expires: 1996-03-03
Abstract
Abstract Method for reducing NOx in combustion effluents comprising introducing urea at elevated temperatures in the presence of oxygen, either as a solid or solution in amounts sufficient to reduce the NOx concentration. Conveniently, the urea may be introduced as a solid powder or as a solution in a hydroxylic solvent, at temperatures in excess of 1300 DEG F. and in the presence of at least 0.1 volume percent oxygen. This invention was made under contract with or supported by the Electric Power Research Institute.
Inventors
- 👤 John K. Arand
- 👤 Lawrence J. Muzio
- 👤 John G. Sotter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 01:00
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/54; B01D53/56; F; F01; F01N; F01N2610/00; F01N2610/02; F01N2610/03; F01N2610/04; F01N3/00; F01N3/08; F01N3/10; F01N3/18; F01N3/20; F01N3/206; F01N3/2066
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
87 words
A process for selectively reducing NO x in a combustion effluent containing NO x comprising: contacting a NO x containing effluent stream in the presence of oxygen with urea, wherein said urea is present in an amount of about 0.1 to 10 moles per moles NO x at a temperature in the range of about 1600° to 2000° F. with the proviso that when an ancillary reducing material is introduced concurrently with the said urea, said temperature is in the range of about 1300° to 2000° F.
Claim 2
Dependent Claim
87 words
A process for selectively reducing NO x in a combustion effluent containing NO x comprising: contacting a NO x containing effluent stream in the presence of oxygen with urea, wherein said urea is present in an amount of about 0.1 to 10 moles per moles NO x at a temperature in the range of about 1600° to 2000° F. with the proviso that when an ancillary reducing material is introduced concurrently with the said urea, said temperature is in the range of about 1300° to 2000° F.
Claim 3
Dependent Claim
30 words
A method according to claim 1, wherein an ancillary reducing material is introduced concurrently with said urea and said temperature is in the range of about 1300° to 2000° F.
Claim 4
Dependent Claim
12 words
A method according to claim 2, wherein said ancillary material is methanol.
Claim 5
Dependent Claim
17 words
A method according to claim 2, wherein said effluent contains 0.1 to 10 volume percent of oxygen.
Claim 6
Dependent Claim
27 words
A method according to claim 1, wherein said urea is present in an amount of from about 0.5 to 2 moles per mole of NO x .
Claim 7
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 8
Dependent Claim
14 words
A method according to claim 1, wherein said urea is introduced as a solution.
Claim 9
Dependent Claim
11 words
A method according to claim 7, wherein said solution is aqueous.
Claim 10
Dependent Claim
11 words
A method according to claim 7, wherein said solution is alkanolic.
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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) | 1983-06-17 | 1983-12-17 | 1984-06-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-06-17 | 1987-12-17 | 1988-06-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-06-17 | 1991-12-17 | 1992-06-17 | $7700.00 | Window Closed / Lapsed |