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US4726302A
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Method of reducing the nitrogen oxide content of a flue gas produced by a fossil-fuel power plant
Assignee: Individual
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Filing: 1986-10-30
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Granted: 1988-02-23
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Expires: 2006-10-30
Abstract
Abstract A method of reducing the nitrogen oxide level in flue gases from a fossil-fuel power plant in which NH3 is admixed with the flue gas as a reducing agent and the nitrogen oxides are largely converted to molecular nitrogen by reducing them with the ammonia in a reactor. Residual ammonia forms NH3 and NH4 substances which deposit and from time to time are taken up in a wash water which is disposed of by introducing it in the boiler.
Inventors
- 👤 Klaus Hein
- 👤 Joachim Konig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:58
CPC Classifications
F; F23; F23J; F23J15/00; F23J15/006; B; B01; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/8621; B01D53/8625; C; C02; C02F; C02F11/00; C02F11/06; Y; Y02; Y02W; Y02W10/00; Y02W10/40
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
181 words
A method of reducing the nitrogen oxide content in a flue gas stream which is produced by a fossil-fuel electricity-generating power plant boiler provided with a flue-gas cleaning apparatus, comprising the steps of: (a) adding NH 3 to a flue gas produced by a fossil-fuel electricity-generating power plant boiler upstream from a reactor of said apparatus into which the flue gas passes admixed with said NH 3 ; (b) causing the NH 3 to react with nitrogen oxides of said flue gas, thereby transforming said nitrogen oxides in said reactor at least predominantly to nitrogen and forming ammonium-compound reaction products at least in part in said reactor; (c) thereafter scrubbing said ammonium-compound reaction products from said flue gas to form a waste water containing NH 3 - or NH 4 -containing substances; and (d) injecting said waste water into a firebox of said boiler directly upon formation in step (c) for thermal decomposition of the NH 3 - or NH 4 -containing substances therein and formation of a flue gas which is further processed in accordance with steps (a) to (c).
Claim 2
Independent Claim
181 words
A method of reducing the nitrogen oxide content in a flue gas stream which is produced by a fossil-fuel electricity-generating power plant boiler provided with a flue-gas cleaning apparatus, comprising the steps of: (a) adding NH 3 to a flue gas produced by a fossil-fuel electricity-generating power plant boiler upstream from a reactor of said apparatus into which the flue gas passes admixed with said NH 3 ; (b) causing the NH 3 to react with nitrogen oxides of said flue gas, thereby transforming said nitrogen oxides in said reactor at least predominantly to nitrogen and forming ammonium-compound reaction products at least in part in said reactor; (c) thereafter scrubbing said ammonium-compound reaction products from said flue gas to form a waste water containing NH 3 - or NH 4 -containing substances; and (d) injecting said waste water into a firebox of said boiler directly upon formation in step (c) for thermal decomposition of the NH 3 - or NH 4 -containing substances therein and formation of a flue gas which is further processed in accordance with steps (a) to (c).
Claim 3
Dependent Claim
39 words
The method as defined in claim 1 wherein said waste water is admixed with a fossil fuel, said method further comprising the step of firing the boiler with said fossil fuel with which said waste water has been admixed.
Claim 4
Dependent Claim
47 words
The method defined in claim 1 wherein said waste water is admixed with a combustion air stream, said method further comprising the step of firing the boiler with a fossil fuel by burning it with said combustion air stream with which said waste water has been admixed.
Claim 5
Dependent Claim
23 words
The method defined in claim 1 wherein said waste water is dispersed in finely divided form in said flue gas in said boiler.
Claim 6
Dependent Claim
58 words
The method defined in claim 1 wherein other NH 3 - and NH 4 -containing waste water is produced in the operation of the power plant of said boiler and said other NH 3 - and NH 4 -containing waste water is also introduced into said boiler for decomposition of the NH 3 and NH 4 + thereof.
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) | 1991-02-22 | 1991-08-24 | 1992-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-22 | 1995-08-24 | 1996-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-22 | 1999-08-24 | 2000-02-23 | $7700.00 | Window Closed / Lapsed |