Abstract: An improved gas flow injector has been developed for use in a combustion system. The gas flow injector has an inner nozzle with tubular configuration for directing a first gas stream to a location distal to the gas flow injector. The inner nozzle has an outlet end portion and a longitudinal central axis. Disposed about the inner nozzle is an outer nozzle having a tubular configuration, for directing a second gas stream to a location proximal to the gas flow injector. A diverter is mounted to the outlet end portion of the inner nozzle and extends at least partially into the second gas stream. The diverter has a surface disposed at an acute angle relative to the longitudinal central axis of the inner nozzle to redirect at least a portion of the second gas stream in a direction transverse to the longitudinal central axis. Also disclosed is a method of injecting a gas into a combustion system using the gas flow injector of this invention.

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.