Duct burner including a perforated flame holder

Abstract

A duct burner includes a perforated flame holder and a fuel header that is spaced away from the perforated flame holder and has a plurality of fuel nozzles. Each of the fuel nozzles is arranged to emit a fuel stream toward a respective portion of the perforated flame holder. A combustion reaction supported by the fuel streams is held within a plurality of apertures extending through the perforated flame holder.

What is claimed is: 
     
         1 . A system, comprising:
 a transport duct configured to carry a gaseous fluid; and   a burner positioned inside the transport duct, the burner including:
 a perforated flame holder having a first face, a second face lying opposite the first face, and a plurality of apertures extending through the perforated flame holder between the first and second faces, and 
 a fuel nozzle positioned and configured to emit a fuel stream toward the first face of the perforated flame holder. 
   
     
     
         2 . The system of  claim 1 , wherein the fuel nozzle is one of a plurality of fuel nozzles, each positioned and configured to emit a fuel stream toward a respective portion of the first face of the perforated flame holder. 
     
     
         3 . The system of  claim 2 , comprising a plurality of pilot nozzles, each positioned adjacent to a respective one of the plurality of fuel nozzles. 
     
     
         4 . The system of  claim 2 , wherein the burner comprises a fuel header extending substantially parallel to the first face of the perforated flame holder, and wherein each of the plurality of fuel nozzles includes a respective aperture extending through a wall of the fuel header. 
     
     
         5 . The system of  claim 4 , wherein the plurality of fuel nozzles is spaced along the fuel header such that, when fuel streams are emitted by the plurality of fuel nozzles, fuel is introduced into the first face of the perforated flame holder substantially evenly along a length of the perforated flame holder. 
     
     
         6 . The system of  claim 4 , wherein each of the plurality of fuel nozzles includes a nozzle tip coupled to the fuel header over the respective aperture. 
     
     
         7 . The system of  claim 6 , wherein the nozzle tips are removable. 
     
     
         8 . The system of  claim 6 , wherein the nozzle tips are attached permanently. 
     
     
         9 . The system of  claim 4 , wherein the burner comprises a plurality of pilot nozzles, each positioned adjacent to a respective one of the plurality of fuel nozzles. 
     
     
         10 . The system of  claim 9 , wherein each of the plurality of fuel nozzles is configured to emit the corresponding fuel stream along a respective fuel stream axis, and wherein each of the plurality of pilot nozzles is configured to emit a pilot fuel stream along a pilot axis that intersects the fuel stream axis of the respective one of the plurality of fuel nozzles. 
     
     
         11 . The system of  claim 9 , comprising a pilot runner extending parallel to the fuel header, and wherein each of the plurality of pilot nozzles includes a respective aperture extending through a wall of the pilot runner. 
     
     
         12 . The system of  claim 11 , comprising a controller configured to control a first flow of fuel to the fuel header and a second flow of fuel to the pilot runner. 
     
     
         13 . The system of  claim 9 , comprising ignition means for igniting a pilot flame at one or more of the plurality of pilot nozzles. 
     
     
         14 . The system of  claim 2 , wherein the burner comprises a first burner unit that includes the perforated flame holder and the plurality of fuel nozzles, and wherein the first burner unit is one of a plurality of burner units comprised by the burner, each having a respective perforated flame holder and a respective plurality of fuel nozzles. 
     
     
         15 . The system of  claim 14 , wherein the perforated flame holder of each of the plurality of burner units includes a first face and a second face lying opposite the first face, and wherein each of the plurality of burner units is positioned such that the first face of each of the respective perforated flame holders is lying in a common plane. 
     
     
         16 . The system of  claim 1 , comprising a heat sink coupled to the perforated flame holder and including a plurality of cooling fins oriented parallel to a direction of fluid flow within the transport duct. 
     
     
         17 . The system of  claim 1 , wherein the burner is positioned such that a direction of flow of a fuel stream from the fuel nozzle toward the first face of the perforated flame holder substantially corresponds to a direction of fluid flow within the transport duct. 
     
     
         18 . A duct burner, comprising:
 a perforated flame holder having a first face, a second face lying opposite the first face, and a plurality of apertures extending through the perforated flame holder between the first and second faces, the first face having an aspect ratio of greater than 2:1;   a fuel header spaced away from, and extending substantially parallel to a long dimension of the first face of the perforated flame holder; and   a plurality of fuel nozzles distributed along the fuel header, each configured to emit a fuel stream toward a respective portion of the first face of the perforated flame holder.   
     
     
         19 . The duct burner of  claim 18 , wherein the plurality of fuel nozzles is spaced along the fuel header such that, when fuel streams are emitted by the plurality of fuel nozzles, fuel is introduced into the first face of the perforated flame holder substantially evenly along a length of the perforated flame holder. 
     
     
         20 . The duct burner of  claim 18 , comprising:
 a pilot runner extending parallel to the fuel header; and   a plurality of pilot nozzles distributed along the pilot runner, each positioned adjacent to a respective one of the plurality of fuel nozzles and configured to emit a pilot stream along an axis that intersects an emission axis of the respective fuel nozzle.   
     
     
         21 . The duct burner of  claim 20 , comprising ignition means for igniting a pilot flame at one or more of the plurality of pilot nozzles. 
     
     
         22 . The duct burner of  claim 20 , comprising a controller configured to control a first flow of fuel to the fuel header and a second flow of fuel to the pilot runner. 
     
     
         23 . The duct burner of  claim 18 , wherein the perforated flame holder is one of a plurality of perforated flame holders comprised by the duct burner. 
     
     
         24 . The duct burner of  claim 23 , wherein each of the plurality of perforated flame holders is arranged with a respective first face lying in a common plane. 
     
     
         25 . The duct burner of  claim 23 , wherein the fuel header is one of a plurality of fuel headers comprised by the duct burner, each spaced away from, and extending substantially parallel to a long dimension of a first face of a respective one of the plurality of perforated flame holders. 
     
     
         26 . A method, comprising:
 supporting a combustion reaction substantially within a plurality of apertures extending through a perforated flame holder positioned within a fluid transport duct by introducing a fuel stream to a first face of the perforated flame holder; and   transferring heat produced by the combustion reaction to a gaseous fluid flowing in the transport duct past the perforated flame holder.   
     
     
         27 . The method of  claim 26 , wherein the supporting a combustion reaction by introducing fuel stream to a first face of the perforated flame holder comprises supporting the combustion reaction by introducing a plurality of fuel streams to respective portions of the first face of the perforated flame holder. 
     
     
         28 . The method of  claim 27 , wherein the supporting a combustion reaction by introducing a plurality of fuel streams to respective portions of the first face of the perforated flame holder comprises emitting each of the plurality of fuel streams from a respective one of a plurality of fuel nozzles distributed along a length of a fuel header that is spaced away from, and lying parallel to the first face of the perforated flame holder. 
     
     
         29 . The method of  claim 28 , comprising, prior to supporting the combustion reaction, preheating the perforated flame holder. 
     
     
         30 . The method of  claim 29 , wherein the preheating the perforated flame holder comprises holding a respective preheat flame in each of the plurality of fuel streams between the respective fuel nozzle and the first face of the perforated flame holder. 
     
     
         31 . The method of  claim 30 , wherein the holding a respective preheat flame in each of the plurality of fuel streams comprises supporting a respective pilot flame adjacent to each of the plurality of fuel streams. 
     
     
         32 . The method of  claim 31 , wherein the supporting a respective pilot flame adjacent to each of the plurality of fuel streams comprises emitting each of the pilot flames from a respective one of a plurality of pilot nozzles distributed along a length of a pilot runner extending parallel to the fuel header. 
     
     
         33 . The method of  claim 26 , wherein the supporting a combustion reaction substantially within a first plurality of apertures extending through a perforated flame holder comprises supporting a first combustion reaction substantially within the plurality of apertures extending through the perforated flame holder, the method further comprising supporting a second combustion reaction substantially within a second plurality of apertures extending through a second perforated flame holder. 
     
     
         34 . The method of  claim 33 , wherein the transferring heat produced by the combustion reaction to a gaseous fluid comprises transferring heat produced by the first combustion reaction to a gaseous fluid flowing in the transport duct past the first perforated flame holder, the method further comprising transferring heat produced by the second combustion reaction to a gaseous fluid flowing in the transport duct past the second perforated flame holder.