Patent ID: 8052950
Filing Date: 2011-11-08
Classification: B01D,F23C,F23J,Y02A

Abstract:
1. A method of decreasing a concentration of nitrogen oxides in a combustion gas flowing through a vessel comprising: a) generating a flue gas in a combustion zone of the vessel, the flue gas containing nitrogen oxides and carbon monoxide; b) providing initial overfire air to a burnout zone of the vessel to oxidize at least some of the carbon monoxide in the flue gas; c) injecting a selective reducing agent into a stream of additional overfire air; d) providing the additional overfire air and injected selective reducing agent to the flue gas flowing through the vessel at a level in the burnout zone downstream of the oxidization of the carbon monoxide by the initial overfire air, and e) reacting the selective reducing agent with the flue gas to reduce the nitrogen oxides.