Abstract: A replacement burner system which facilitates reduction of nitrous oxide produced during combustion of a fuel. The replacement burner system comprising a fuel supply duct having an inlet and an outlet with a fuel deflector located within the fuel supply duct to facilitate redistribution of a flow of the fuel. An adjustable coal nozzle is located within the fuel supply duct between the fuel deflector and the outlet. An exterior surface of the fuel supply duct supports an air swirling device, and the air swirling device obstructs between 65% and 75% of the transverse flow area, located between an exterior surface of the fuel supply duct and the inwardly facing surface of the venturi register, after the replacement burner system is accommodated within the windbox of a combustion boiler.

Abstract: A combustion boiler for burning fuel and producing heat to generate steam. A method of minimizing discharging of nitrogen oxides from a combustion boiler comprising the steps of spraying a reducing agent into an overfire air stream and supplying the overfire air stream to the combustion boiler. Vaporizing the sprayed reducing agent at least within about 0.1 seconds of the sprayed reducing agent entering the combustion boiler and reacting the vaporized reducing agent with the nitrogen oxides within the combustion chamber to reduce the nitrogen oxides and minimize discharge of nitrogen oxides from the combustion boiler.

Abstract: A replacement burner system which facilitates reduction of nitrous oxide produced during combustion of a fuel. The replacement burner system comprising a fuel supply duct having an inlet and an outlet with a fuel deflector located within the fuel supply duct to facilitate redistribution of a flow of the fuel. An adjustable coal nozzle is located within the fuel supply duct between the fuel deflector and the outlet. An exterior surface of the fuel supply duct supports an air swirling device, and the air swirling device obstructs between 65% and 75% of the transverse flow area, located between an exterior surface of the fuel supply duct and the inwardly facing surface of the venturi register, after the replacement burner system is accommodated within the windbox of a combustion boiler.

Abstract: A combustion boiler for burning fuel and producing heat to generate steam. A method of minimizing discharging of nitrogen oxides from a combustion boiler comprising the steps of spraying a reducing agent into an overfire air stream and supplying the overfire air stream to the combustion boiler. Vaporizing the sprayed reducing agent at least within about 0.1 seconds of the sprayed reducing agent entering the combustion boiler and reacting the vaporized reducing agent with the nitrogen oxides within the combustion chamber to reduce the nitrogen oxides and minimize discharge of nitrogen oxides from the combustion boiler. The reducing agent is nearly substantially instantaneous evaporated/gasified by the high energy of the reducing agent injection system.

Abstract: A method and apparatus are described for reducing NO.sub.x in a combustion zone such as a boiler by spatially selectively injecting a cooling fluid into the combustion zone so that the fluid is entrained to intersect an identifiable NO.sub.x producing zone. The cooling fluid can be water or a gas or mixture of them and whose temperature is sufficiently low or whose combined mass flow and temperature are sufficiently low so that the cooling fluid can reach the NO.sub.x producing zone and cool it to a temperature where the NO.sub.x production is significantly reduced. In one embodiment of the invention a cyclone boiler has a number of identifiable NO.sub.x producing zones. Several of these are targeted by spatially distinct cooling fluid streams placed at strategic locations.