Counterflow fuel injection nozzle in a burner-boiler system

摘要

A counterflow fuel injection nozzle for injecting fuel is disclosed. The nozzle includes a nozzle wall having an interior surface that defines a nozzle interior, the interior for receiving a fuel therein. The nozzle further has a fuel passageway formed in the nozzle wall for distributing the fuel from the interior to a location exterior of the nozzle, the fuel distributed to the exterior location in a fuel flow injection direction. An airstream is provided in a prevailing air flow direction in the location exterior of the nozzle. At least one vector component of the fuel flow injection direction opposes at least one vector component of the prevailing air flow direction. In this manner, by distributing fuel into an air flow at a counterflow angle, improved control of mixing of the fuel in the air is achieved. The counterflow nozzle may be included as part of a new burner or as a retrofit to existing burners in order to incorporate counterflow mixing. Advantageously, burner turndown ratios and stability are enhanced through the use of the counterflow fuel injection nozzles with burners that use FGR (i.e., have lower O2 in combustion air supplied to the burner).