Fuel nozzle assembly for a burner including a perforated flame holder

Abstract

A fuel nozzle assembly includes one or more tapered fuel nozzles. Each tapered fuel nozzle includes an acute trailing edge or tip at a top portion of the fuel nozzle. One or more fuel orifices are arranged proximate the acute trailing edge or tip. A tapered fuel nozzle having a toroidal airfoil structure includes a fuel channel to distribute a fuel to the fuel orifice(s). The fuel nozzle assembly may be provided as part of a burner system, including a perforated flame holder, and associated method, in which the fuel nozzle assembly is oriented to direct fuel from the fuel orifices toward the perforated flame holder.

1 .- 61 . (canceled) 
     
     
         62 . A method, comprising:
 outputting an oxidant into a furnace volume;   outputting a fuel stream including a fuel into the furnace volume;   mixing the oxidant and the fuel stream;   supporting a perforated flame holder in the furnace volume separated from the fuel and oxidant source by a dilution distance selected to enable complete mixing of the oxidant with the fuel stream;   imparting a swirling motion to at least one of the oxidant and the fuel stream;   receiving the fuel stream mixed with the oxidant at the perforated flame holder; and   supporting a combustion reaction of the fuel and oxidant within the perforated flame holder;   wherein the dilution distance corresponds to a distance at which the complete mixing of the fuel and the oxidant would not occur in the absence of imparting the swirling motion.   
     
     
         63 . (canceled) 
     
     
         64 . The method of  claim 62 , comprising outputting the fuel stream from a fuel nozzle, and wherein imparting the swirling motion includes outputting the fuel stream from the fuel nozzle with a fuel swirling motion. 
     
     
         65 . The method of  claim 64 , wherein outputting the fuel stream includes outputting a plurality of fuel streams each from a respective aperture of the fuel nozzle. 
     
     
         66 .- 69 . (canceled) 
     
     
         70 . The method of  claim 65 , including passing the fuel stream through the respective aperture at a compound angle with respect to a central axis of the fuel nozzle. 
     
     
         71 . The method of  claim 62 , wherein imparting the swirling motion includes imparting the swirling motion to the oxidant before the oxidant contacts the fuel stream. 
     
     
         72 .- 74 . (canceled) 
     
     
         75 . The method of  claim 71 , wherein imparting the swirling motion includes passing the oxidant through a swirler and propelling the oxidant toward the perforated flame holder with the swirling motion. 
     
     
         76 . The method of  claim 75 , wherein outputting the fuel stream includes outputting the fuel stream in a direction transverse to a primary direction of the oxidant downstream from the swirler. 
     
     
         77 . (canceled) 
     
     
         78 . The method of  claim 62 , wherein the complete mixing of the fuel and the oxidant is such that there is less than a 1% variation in concentration of the fuel in the oxidant. 
     
     
         79 . The method of  claim 62 , wherein the complete mixing of the fuel and the oxidant is such that there is less than a 0.1% variation in concentration of the fuel in the oxidant. 
     
     
         80 . A combustion system, comprising:
 a fuel and oxidant source configured to output an oxidant and a fuel stream including a fuel into a furnace volume, the fuel and oxidant source including a swirler configured to impart a swirling motion to at least one of the fuel stream and the oxidant, and   a perforated flame holder positioned to receive the fuel stream and being configured to support a combustion reaction of the fuel and the oxidant within the perforated flame holder, the perforated flame holder being separated from the fuel and oxidant source by a dilution distance selected to enable complete mixing of the oxidant with the fuel stream;   wherein the dilution distance corresponds to a distance at which the compete mixing of the fuel and the oxidant would not occur in the absence of imparting the swirling motion.   
     
     
         81 . (canceled) 
     
     
         82 . The combustion system of  claim 80 , wherein the fuel and oxidant source includes a fuel nozzle configured to output the fuel stream, wherein the fuel nozzle includes a plurality of apertures each configured to output a respective fuel stream including the fuel, and wherein each fuel channel conveys the respective fuel stream at a respective compound angle to a central axis of the fuel nozzle. 
     
     
         83 .- 84 . (canceled) 
     
     
         85 . The combustion system of  claim 82 , wherein the dilution distance is less than 100 times a diameter of one of the apertures. 
     
     
         86 . The combustion system of  claim 82 , wherein the dilution distance is less than 50 times a diameter of one of the apertures. 
     
     
         87 . The combustion system of  claim 82 , wherein the dilution distance is less than 20 times a diameter of one of the apertures. 
     
     
         88 . The combustion system of  claim 80 , wherein the swirler is configured to impart the swirling motion to the oxidant prior to mixing with the fuel stream. 
     
     
         89 .- 90 . (canceled) 
     
     
         91 . The combustion system of  claim 80 , wherein the fuel and oxidant source includes a barrel register configured to draft the oxidant into the furnace volume. 
     
     
         92 . The combustion system of  claim 80 , wherein the dilution distance corresponds to a distance at which complete mixing of the fuel and the oxidant is such that there is either:
 a 1% variation in concentration of the fuel in the oxidant; or   a 0.1% variation in concentration of the fuel in the oxidant.   
     
     
         93 . The combustion system of  claim 80 , wherein the perforated flame holder is a reticulated ceramic perforated flame holder. 
     
     
         94 . The combustion system of  claim 93 , wherein the perforated flame holder includes a plurality of reticulated fibers. 
     
     
         95 . The combustion system of  claim 94 , wherein the perforated flame holder includes zirconia. 
     
     
         96 . The combustion system of  claim 94 , wherein the perforated flame holder includes alumina silicate. 
     
     
         97 . The combustion system of  claim 94 , wherein the perforated flame holder includes silicon carbide. 
     
     
         98 . The combustion system of  claim 94 , wherein the reticulated fibers are formed from extruded mullite. 
     
     
         99 . The combustion system of  claim 94 , wherein the reticulated fibers are formed from cordierite. 
     
     
         100 . (canceled) 
     
     
         101 . The combustion system of  claim 94 , wherein the perforated flame holder includes about 100 pores per square inch of surface area. 
     
     
         102 . The combustion system of  claim 94 , wherein perforations are formed as passages between the reticulated fibers. 
     
     
         103 . The combustion system of  claim 94 , wherein perforations are branching perforations. 
     
     
         104 . The combustion system of  claim 94 , wherein the perforated flame holder includes:
 an input face corresponding to an extent of the reticulated fibers proximal to one or more primary fuel distributors; and   an output face corresponding to an extent of the reticulated fibers distal to the one or more primary fuel distributors; and   wherein perforations extend between the input face and the output face.   
     
     
         105 . (canceled) 
     
     
         106 . The combustion system of  claim 104 , wherein the perforated flame holder is configured to support at least a portion of the combustion reaction within the perforated flame holder between the input face and the output face. 
     
     
         107 . A combustion system, comprising:
 a perforated flame holder positioned in a furnace volume;   a preheating flame holder positioned in the furnace volume;   a preheating fuel nozzle configured to output a preheating fuel stream including a preheating fuel onto the preheating flame holder, the preheating flame holder being configured to hold a preheating combustion reaction supported by the preheating fuel stream;   an oxidant source configured to output an oxidant into the furnace volume; and   a main fuel nozzle including a plurality of apertures each configured to output a respective fuel stream including a main fuel with a trajectory selected to mix with the oxidant before reaching the perforated flame holder, the perforated flame holder being configured to support a second combustion reaction of the fuel and the oxidant substantially within the perforated flame holder.   
     
     
         108 . The combustion system of  claim 107 , wherein the main fuel nozzle includes a plurality of fuel channels each configured to convey a respective fuel stream to a respective aperture. 
     
     
         109 . The combustion system of  claim 108 , wherein each fuel channel conveys the respective fuel stream at a respective compound angle with respect to a central axis of the main fuel nozzle. 
     
     
         110 . The combustion system of  claim 107 , further comprising a swirler configured to impart a rotational motion to the oxidant prior to mixing with the main fuel. 
     
     
         111 . The combustion system of  claim 107 , wherein the oxidant source includes a blower configured to blow the oxidant into the furnace volume. 
     
     
         112 . The combustion system of  claim 107 , wherein the oxidant source drafts the oxidant into the furnace volume. 
     
     
         113 . The combustion system of  claim 107 , further comprising:
 a temperature sensor configured to sense a temperature of the perforated flame holder; and   a controller configured to receive from the temperature sensor a temperature signal indicative of the temperature of the perforated flame holder;   wherein the controller and the preheating fuel nozzle are configured to output the preheating fuel stream until the preheating combustion reaction has heated the perforated flame holder to a threshold temperature and then to cease outputting the preheating fuel stream after the perforated flame holder has reached the threshold temperature.   
     
     
         114 . (canceled) 
     
     
         115 . The combustion system of  claim 113 , wherein the threshold temperature is a temperature at which the perforated flame holder can sustain combustion of the fuel and the oxidant. 
     
     
         116 .- 118 . (canceled) 
     
     
         119 . The combustion system of  claim 113 , wherein the controller is configured to cause the main fuel nozzle to output the main fuel streams when the perforated flame holder has reached the threshold temperature. 
     
     
         120 . The combustion system of  claim 107 , wherein the preheating flame holder includes a toroidal shape defining a central gap. 
     
     
         121 . The combustion system of  claim 120 , wherein the preheating fuel nozzle is positioned in the central gap. 
     
     
         122 . The combustion system of  claim 121 , further including a plurality of the preheating fuel nozzle configured to output respective preheating fuel streams onto the preheating flame holder. 
     
     
         123 . The combustion system of  claim 120 , wherein the main fuel nozzle extends through the central gap. 
     
     
         124 . The combustion system of  claim 107 , wherein the main fuel nozzle is closer to the perforated flame holder than is the preheating flame holder. 
     
     
         125 . The combustion system of  claim 124 , wherein the main fuel nozzle is closer to the perforated flame holder than is the preheating fuel nozzle. 
     
     
         126 . The combustion system of  claim 125 , wherein the preheating flame holder includes a flame holding surface facing the perforated flame holder and configured to hold the preheating flame. 
     
     
         127 . The combustion system of  claim 107 , wherein the perforated flame holder is a reticulated ceramic perforated flame holder. 
     
     
         128 . A method, comprising:
 introducing an oxidant into a furnace volume;   outputting, from a preheating fuel nozzle, a preheating fuel stream including a preheating fuel onto a preheating flame holder positioned in the furnace volume;   preheating a perforated flame holder to a threshold temperature by supporting a preheating flame of the preheating fuel and the oxidant on the preheating flame holder;   outputting a plurality of primary fuel streams with respective trajectories configured to mix with the oxidant, the primary fuel streams including a primary fuel;   receiving the fuel streams mixed with the oxidant in the perforated flame holder; and   supporting, after the perforated flame holder has reached the threshold temperature, a combustion reaction of the fuel and the oxidant within the perforated flame holder.   
     
     
         129 . (canceled) 
     
     
         130 . The method of  claim 128 , further comprising outputting the primary fuel streams each at a respective compound angle with respect to a central axis of the fuel nozzle. 
     
     
         131 . (canceled) 
     
     
         132 . The method of  claim 128 , further comprising outputting the primary fuel streams with a vortex motion. 
     
     
         133 .- 137 . (canceled) 
     
     
         138 . The method of  claim 128 , wherein the threshold temperature is a temperature at which the perforated flame holder can sustain combustion of the fuel and the oxidant. 
     
     
         139 . (canceled)