Abstract: A method for operating a fuel-fired furnace including at least one burner is provided. The method includes channeling a first fluid flow to the at least one burner at a first predetermined velocity, and channeling a second fluid flow to the at least one burner at a second predetermined velocity during a first mode of operation of the at least one burner. The second predetermined velocity is different than the first predetermined velocity.

Abstract: A fuel flexible furnace, including a main combustion zone, a reburn zone downstream from the main combustion zone, and a delivery system operably coupled to supplies of biomass and coal and configured to deliver the biomass and the coal as ingredients of first and reburn fuels to the main combustion zone and the reburn zone, with each fuel including flexible quantities of the biomass and/or the coal. The flexible quantities are variable with the furnace in an operating condition.

Abstract: A combustion apparatus for combusting including: a boiler defining an enclosed flue gas path having a combustion zone and a burnout zone, wherein flue gas is formed in the combustion zone and the combustion flue gas comprising nitrogen oxides; a fuel injector aligned with and introducing fuel into the combustion zone and a combustion air injector aligned with and introducing air into the combustion zone; an overfire air system adjacent the burnout zone comprising an overfire air port adjacent the burnout zone and through which overfire air flows into the burnout zone, and a nitrogen reagent injector having an outlet aligned with the overfire air system and injecting nitrogen reagent gas or small droplets into said overfire air, wherein said small droplets have an average diameter of no greater than 50 microns.

Abstract: A method of decreasing the concentration of nitrogen oxides in a combustion gas flowing through a vessel including the steps of: generating a flue gas in a combustion zone of the vessel, the flue gas containing nitrogen oxides and carbon monoxide; providing overfire air into a burnout zone of the vessel from a first injector of the overfire air to oxidize at least some of the carbon monoxide in the flue gas; injecting a selective reducing agent concurrent with the overfire air at a level in the burnout zone downstream of the first injector of overfire air and downstream of the oxidization of the carbon monoxide; and reacting the selective reducing agent with the flue gas to reduce the nitrogen oxides.

Abstract: A method of decreasing the concentration of nitrogen oxides in a combustion flue gas in which a nitrogen reducing agent is introduced together with the overfire air to mixes with the products of primary combustion along with the overfire air. The nitrogen agent reduced NOx as it passes through the temperature regime that is optimum for the NOx reduction as overfire air and flue gas mix. The transition from low to high temperature effectively eliminates ammonia slip. Additionally, the nitrogen agent may be mixed with the overfire air stream in such a manner that it is optimally shielded from early mixing with the products of primary combustion, where a portion of the overfire air reacts initially with any residual carbon monoxide (CO) that would otherwise interfere with the NOx reduction chemistry.

Abstract: A method of decreasing a concentration of nitrogen oxides in a combustion gas flowing through a vessel including: generating a flue gas in a combustion zone of the vessel, the flue gas containing nitrogen oxides and carbon monoxide; providing overfire air into a burnout zone of the vessel from a first injector of overfire air to oxidize at least some of the carbon monoxide in the flue gas; injecting a selective reducing agent concurrent with overfire air at a level in the burnout zone downstream of the first injector of overfire air and downstream of the oxidization of the carbon monoxide, and reacting the selective reducing agent with the flue gas to reduce the nitrogen oxides.

Abstract: A system for reducing fouling and improving efficiency in a coal-fired power plant that may include: 1) an analyzer grid, the analyzer grid including a plurality of sensors that measure gas characteristics through an approximate cross section of a flow through a boiler of the coal-fired power plant; 2) a plurality of air injectors with enhanced controllability; 3) means for analyzing the measurements of the gas characteristics; and 4) means for controlling the air injectors with enhanced controllability. The analysis of the measurements of the gas characteristics may include analyzing the measurements to determine zones of non-homogeneous flow.

Abstract: A boiler incorporates an overfire air injection system for reducing NOx emissions. The boiler comprises a combustion device including a plurality of main burners supplied with fossil fuel and air for burning in a combustion zone, where the burners produce flue gases that flow from the combustion zone into a burnout zone. The boiler further comprises at least one overfire air injector for supplying overfire air to the combustion device and at least one booster overfire air injector for supplying high-pressure air to the combustion device.

Abstract: A method to reduce mercury in gas emissions from the combustion of coal is disclosed. Mercury emissions can be reduced by staging combustion process and/or reducing boiler excess oxygen. Fly ash formed under combustion staging conditions is more reactive towards mercury than fly ash formed under typical combustion conditions. Reducing boiler excess oxygen can also improve ability of fly ash to adsorb mercury.

Abstract: A method to reduce mercury in gas emissions from the combustion of coal is disclosed. Mercury emissions can be reduced by staging combustion process and/or reducing boiler excess oxygen. Fly ash formed under combustion staging conditions is more reactive towards mercury than fly ash formed under typical combustion conditions. Reducing boiler excess oxygen can also improve ability of fly ash to adsorb mercury.

Abstract: A method to reduce mercury in gas emissions from the combustion of coal is disclosed. Mercury emissions can be reduced by staging combustion process and/or reducing boiler excess oxygen. Fly ash formed under combustion staging conditions is more reactive towards mercury than fly ash formed under typical combustion conditions. Reducing boiler excess oxygen can also improve ability of fly ash to adsorb mercury.

Abstract: A method to reduce mercury in gas emissions from the combustion of coal is disclosed. Mercury emissions can be reduced by staging combustion process and/or reducing boiler excess oxygen. Fly ash formed under combustion staging conditions is more reactive towards mercury than fly ash formed under typical combustion conditions. Reducing boiler excess oxygen can also improve ability of fly ash to adsorb mercury.

Abstract: A method to reduce mercury in gas emissions from the combustion of coal is disclosed. Mercury emissions can be reduced by staging combustion process and/or reducing boiler excess oxygen. Fly ash formed under combustion staging conditions is more reactive towards mercury than fly ash formed under typical combustion conditions. Reducing boiler excess oxygen can also improve ability of fly ash to adsorb mercury.

Abstract: A method of decreasing the concentration of nitrogen oxides in a combustion flue gas is disclosed in which the nitrogen reducing agent, either in gaseous form, as small particles, or as small droplets of an aqueous solution, is introduced together with the overfire air in such a way that it mixes with the products of primary combustion along with the overfire air. The nitrogen agent reduced NOx as it passes through the temperature regime that is optimum for the NOx reduction as overfire air and flue gas mix. The transition from low to high temperature effectively eliminates ammonia slip. Additionally, the nitrogen agent may be mixed with the overfire air stream in such a manner that it is optimally shielded from early mixing with the products of primary combustion, where a portion of the overfire air reacts initially with any residual carbon monoxide (CO) that would otherwise interfere with the NOx reduction chemistry.

Abstract: An overfire air injector for use in a fossil fuel-fired combustion device includes a cylindrical nozzle having an outlet end formed with a step diffuser comprising one or more radial steps that enlarge the outlet end of the nozzle. An atomizer lance may be mounted within the nozzle, having a discharge orifice at the outlet end of the nozzle, for supplying a reducing agent to the overfire air to reduce NOx emissions.

Abstract: A combustion vessel having a combustion zone; a burnout zone downstream of the combustion zone; an overfire air chamber adjacent the burnout zone, wherein the chamber has an upstream air injector and a downstream air injector, and an agent injector for injecting a selective reducing agent into the burnout zone, wherein the agent injector extends through the downstream air injector.

Abstract: An overfire air injector for use in a fossil fuel-fired combustion device includes a cylindrical nozzle having an outlet end formed with a step diffuser comprising one or more radial steps that enlarge the outlet end of the nozzle. An atomizer lance may be mounted within the nozzle, having a discharge orifice at the outlet end of the nozzle, for supplying a reducing agent to the overfire air to reduce NOx emissions.

Abstract: A method of optimizing operation of a fossil fuel fired boiler includes, in an exemplary embodiment, providing a plurality of sensors positioned in different spatial positions within the fossil fuel fired boiler. The method also includes recording sensor outputs, identifying spatial combustion anomalies indicated by sensor outputs, identifying burners responsible for the spatial combustion anomalies, and adjusting air flow of responsible burners to alleviate the spatial combustion anomalies.

Abstract: An apparatus and method for high velocity injection of a stream of fluid fuel into a stream of NOx containing combustion effluents downstream of a primary combustion zone, without the use of recirculated flue gas or other carrier gas. The apparatus includes a fuel introducing member that has a fuel receiving end for receiving fluid fuel from a fuel source and a fuel injection end for injecting the fluid fuel into the stream of combustion effluents. A fuel passage is in fluid communication with the fuel receiving end and the fuel injection end of the fuel introducing member. A means for increasing the velocity of the fluid fuel, without the need of a carrier gas, is associated with the fuel introducing member.

Abstract: An apparatus for controlling the emissions of nitrogen oxides from a combustion system includes at least one nozzle assembly having an array of openings for delivering droplets of a fluid chemical agent to a flue gas within the combustion system; a controller operatively coupled to the at least one nozzle assembly for controlling the size and distribution of each droplet; an excitation mechanism operatively coupled to the at least nozzle assembly for providing additional control over the size and distribution of each droplet; and the array of openings arranged for deflecting the droplets to prevent droplet collisions.