초록 ▼

A combustion method is provided for carrying out combustion with reduced generation of nitrogen oxides. The combustion method involves partially combusting a fluid fuel stream with a low velocity oxidant and thereafter mixing and combusting the resulting product with a secondary oxidant stream dilut

A combustion method is provided for carrying out combustion with reduced generation of nitrogen oxides. The combustion method involves partially combusting a fluid fuel stream with a low velocity oxidant and thereafter mixing and combusting the resulting product with a secondary oxidant stream diluted with ambient gas. The velocity of the secondary oxidant stream is either increased to reduce the nitrogen oxides emission level or adjusted to provide the desired secondary oxidant/low velocity oxidant ratio which is useful for further decreasing the formation of nitrogen oxides. Normally, increasing the ratio and/or velocity further decreases the nitrogen oxides emission level. When liquid fuel is employed, it is atomized with atomizing fluid in such a manner to produce a liquid fuel stream having a very narrow spray angle. The production of such a stream allows the burner to be operated without water cooling. Moreover, such a stream, when combined with the above combustion method, unexpectedly provides effective and efficient combustion with reduced generation of nitrogen oxides.

대표청구항 ▼

A process for combusting fluid fuel with reduced nitrogen oxides generation, said process comprising: (a) injecting at least one fluid fuel stream into a combustion zone through a nozzle having an opening at a tip that is recessed from an internal opening of at least one refractory port defined by a

A process for combusting fluid fuel with reduced nitrogen oxides generation, said process comprising: (a) injecting at least one fluid fuel stream into a combustion zone through a nozzle having an opening at a tip that is recessed from an internal opening of at least one refractory port defined by at least one wall surrounding said combustion zone; (b) shrouding at least a portion of a length of said at least one fluid fuel stream with a substoichiometric amount of at least one primary oxidant stream injected at a velocity less than 200 feet per and partially combusting said fluid fuel with the primary oxidant to form partially combusted products; (c) injecting at least one secondary oxidant stream angled away from said fluid fuel stream and primary oxidant stream, or from a point spaced from where said fluid fuel and primary oxidant streams are injected, or from an opposite point from where said fluid fuel and primary oxidant streams are injected, wherein said secondary oxidant stream has a spacing distance, an ejection angle and a velocity that establishes a gas circulation pattern that promotes entrainment of ambient gas to dilute said at least one secondary stream, and wherein said at least one secondary stream injected is such that the volume ratio of said secondary oxidant to said primary oxidant is greater than 2.4:1 but less than 9:1; (d) diluting said secondary oxidant stream with a large volume of ambient gas containing an oxygen concentration of about 0.5 to about 15 percent by volume to form a diluted stream; and (e) mixing said diluted stream to said partially combusted product and thereafter combusting said partially combusted product with the oxygen in said diluted stream.