Method of reducing the nitrogen oxide content of a flue gas produced by a fossil-fuel power plant
OwnerKlaus Hein, Joachim Koniginventors
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Abstract
A method of reducing the nitrogen oxide level in flue gases from a fossil-fuel power plant in which NH.sub.3 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 NH.sub.3 and NH.sub.4 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.
Claims5
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.sub.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.sub.3 ;
- (b) causing the NH.sub.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.sub.3 - or NH.sub.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.sub.3 - or NH.sub.4 -containing substances therein and formation of a flue gas which is further processed in accordance with steps (a) to (c).
Dependencies are inferred from the claim text.