Burner system including a moveable perforated flame holder

Abstract

A burner includes a perforated flame holder configured to be disposed at a plurality of locations relative to a fuel and air source.

1 . A burner system, comprising:
 a fuel and oxidant source;   a perforated flame holder configured to receive fuel and oxidant from the fuel and oxidant source and support a combustion reaction collectively in a plurality of perforations defined by the perforated flame holder; and   a flame holder support mechanism configured to support the perforated flame holder at each of a plurality of selected positions at respective distances from the fuel and oxidant source.   
     
     
         2 . The burner system of  claim 1 , further comprising:
 a flame holder actuator configured to move the perforated flame holder between the plurality of positions.   
     
     
         3 . The burner system of  claim 2 , further comprising:
 a flame holder controller operatively coupled to the flame holder actuator;   wherein the flame holder controller is configured to receive a command to position the flame holder and responsively drive the flame holder actuator to move the perforated flame holder to the commanded position.   
     
     
         4 . The burner system of  claim 2 , further comprising:
 a flame holder controller operatively coupled to the flame holder actuator;   wherein the flame holder controller is configured to sense a combustion parameter, determine a flame holder position, and drive the flame holder actuator to move the perforated flame holder to the determined flame holder position.   
     
     
         5 . A burner, comprising:
 a body defining a combustion chamber having a main axis;   a plurality of rails operatively coupled to the body, the plurality of rails being disposed parallel to the main axis; and   a flame holder disposed in the combustion chamber and configured to be disposed at a plurality of positions along the plurality of rails.   
     
     
         6 . The burner of  claim 5 , wherein the flame holder comprises a perforated flame holder. 
     
     
         7 . The burner of  claim 5 , wherein the flame holder comprises a perforated flame holder including a perforated flame holder body defining a plurality of perforations aligned to receive the fuel and oxidant mixture from the fuel and oxidant source;
 wherein the perforations are configured to collectively hold a combustion reaction supported by the fuel and oxidant mixture.   
     
     
         8 . The burner of  claim 7 , wherein the perforated flame holder is configured to hold the combustion reaction substantially within the perforated flame holder body when the perforated flame holder is disposed at one or more of the plurality of positions. 
     
     
         9 . The burner of  claim 7 , wherein the perforated flame holder body is bounded by a proximal surface disposed to receive the fuel and oxidant mixture when the perforated flame holder is disposed at one or more of the plurality of positions corresponding to a working position, a distal surface facing away from the fuel and oxidant source, and a peripheral surface defining a lateral extent of the perforated flame holder; and
 wherein the plurality of perforations defined by the perforated flame holder body extend from the proximal surface to the distal surface.   
     
     
         10 . The burner of  claim 7 , wherein, when the perforated flame holder is disposed at one or more of the plurality of positions, the perforated flame holder is configured to hold the combustion reaction substantially within the perforated flame holder body such that a majority of the combustion reaction occurs between a proximal surface and a distal surface of the perforated flame holder. 
     
     
         11 . The burner of  claim 7 , wherein, when the perforated flame holder is disposed at one or more of the plurality of positions, the perforated flame holder is configured to hold the combustion reaction substantially within the perforated flame holder body such that at least 80% of the combustion reaction occurs between a proximal surface and a distal surface of the perforated flame holder. 
     
     
         12 . The burner of  claim 7 , wherein, when the perforated flame holder is disposed at one or more of the plurality of positions, the perforated flame holder is configured to receive heat from the combustion reaction and output a portion of the received heat as thermal radiation to heat-receiving structures in or adjacent to the combustion chamber. 
     
     
         13 . The burner of  claim 7 , wherein, when the perforated flame holder is disposed at one or more of the plurality of positions, the perforated flame holder is configured to:
 receive heat from the combustion reaction;   output a portion of the received heat as thermal radiation; and   output another portion of the received heat to the fuel and oxidant mixture received at a proximal surface of the perforated flame holder.   
     
     
         14 . The burner of  claim 7 , wherein the perforated flame holder has a width dimension W FH  between opposite sides of the peripheral surface at least twice a thickness dimension T FH  between the proximal surface and a distal surface. 
     
     
         15 . The burner of  claim 14 , wherein the perforated flame holder includes a plurality of tiles coupled together and each having a width dimension W FT  less than the width dimension W FH  of the perforated flame holder. 
     
     
         16 . The burner of  claim 14 , wherein the perforated flame holder has a width dimension W FH  between opposite sides of the peripheral surface at least three times a thickness dimension T FH  between the proximal surface and the distal surface. 
     
     
         17 . The burner of  claim 14 , wherein the perforated flame holder has a width dimension W FH  between opposite sides of the peripheral surface at least six times a thickness dimension T FH  between the proximal surface and the distal surface. 
     
     
         18 . The burner of  claim 14 , wherein the perforated flame holder has a width dimension W FH  between opposite sides of the peripheral surface at least nine times a thickness dimension T FH  between the proximal surface and the distal surface. 
     
     
         19 . The burner of  claim 7 , wherein the perforated flame holder has a width dimension W FH  less than a width W of the combustion chamber. 
     
     
         20 . The burner of  claim 7 , wherein the perforated flame holder is formed from a refractory material. 
     
     
         21 . The burner of  claim 7 , wherein the perforated flame holder is formed from an aluminum silicate material. 
     
     
         22 . The burner of  claim 21 , wherein the perforated flame holder is formed from mullite or cordierite. 
     
     
         23 . The burner of  claim 7 , wherein the perforated flame holder tiles are rectangular. 
     
     
         24 . The burner of  claim 7 , wherein the perforated flame holder tiles are square. 
     
     
         25 . The burner of  claim 7 , wherein the perforated flame holder tiles each include a keyed shape selected to interlock with neighboring flame holder tiles. 
     
     
         26 . The burner of  claim 25 , wherein the perforated flame holder tiles are tapered to restrict motion in one direction. 
     
     
         27 . The burner of  claim 5 , further comprising:
 a fuel and oxidant source disposed to output fuel and oxidant through the combustion chamber in a direction having a component parallel to the main axis;   wherein the plurality of positions correspond to a respective plurality of distances from the fuel and oxidant source.   
     
     
         28 . The burner of  claim 5 , wherein the plurality of rails collectively support a weight of the flame holder through a combustion chamber wall. 
     
     
         29 . The burner of  claim 5 , wherein a largest dimension of the perforated flame holder is substantially normal to the fluid flow direction. 
     
     
         30 . The burner of  claim 5 , further comprising:
 one or more saddles operatively coupled to the flame holder and configured to support the flame holder relative to each of the plurality of rails.   
     
     
         31 . The burner of  claim 30 , further comprising:
 a carriage operatively coupled to each saddle and to the flame holder;   wherein the carriage is configured to support the weight of the flame holder through the saddles and the plurality of rails.   
     
     
         32 . The burner of  claim 31 , further comprising:
 a mechanical linkage operatively coupled to the flame holder, the mechanical linkage being configured to convey physical force to cause the flame holder to move between positions along the rails.   
     
     
         33 . The burner of  claim 32 , wherein the mechanical linkage comprises a cable. 
     
     
         34 . The burner of  claim 33 , further comprising one or more winches disposed outside the combustion chamber and operatively coupled to the cable. 
     
     
         35 . The burner of  claim 34 , wherein the one or more winches comprises a hand-crank winch. 
     
     
         36 . The burner of  claim 34 , wherein the one or more winches comprises a synchronous drive motor. 
     
     
         37 . The burner of  claim 34 , wherein the one or more winches comprises a servo-controlled motor. 
     
     
         38 . The burner of  claim 32 , wherein the mechanical linkage comprises a screw; and
 further comprising:   a nut operatively coupled to the carriage and configured to convert rotary motion received from the lead screw into translational motion of the flame holder.   
     
     
         39 . The burner of  claim 30 , wherein the mechanical linkage comprises a ball screw; and
 further comprising:   a nut operatively coupled to the carriage and configured to convert rotary motion received from the ball screw into translational motion of the flame holder.   
     
     
         40 . The burner of  claim 5 , wherein the flame holder is configured to move between positions during operation of the burner. 
     
     
         41 . The burner of  claim 5 , wherein the flame holder is configured to be locked into position during operation. 
     
     
         42 . The burner of  claim 5 , wherein the plurality of positions include a first position adjacent to a fuel and air source. 
     
     
         43 . The burner of  claim 42 , wherein the flame holder is configured to hold a fuel rich flame adjacent to the fuel and air source when the flame holder is at the first position. 
     
     
         44 . The burner of  claim 43 , wherein the flame holder is selected to be positioned at the first position and to hold the fuel rich flame adjacent to the fuel and air source during a start-up operating regime;
 whereby the fuel rich flame causes the flame holder to be heated to an elevated operating temperature.   
     
     
         45 . The burner of  claim 42 , wherein the flame holder includes a distal surface disposed away from the fuel and air source; and
 wherein the flame holder is configured to hold a conventional flame extending away from the flame holder distal surface when the flame holder is at the first position.   
     
     
         46 . The burner of  claim 42 , wherein the flame holder includes a distal surface disposed away from the fuel and oxidant source; and 
       wherein the flame holder is configured to pass fuel and air through the flame holder to the flame holder distal surface when the flame holder is at the first position. 
     
     
         47 . The burner of  claim 5 , wherein the plurality of positions includes at least one working position distal from the fuel and oxidant source. 
     
     
         48 . The burner of  claim 5 , wherein the flame holder is configured to hold a lean combustion reaction substantially contained by a plurality of perforations formed through the flame holder when the flame holder is at the distal working position. 
     
     
         49 . The burner of  claim 48 , wherein the flame holder includes a proximal surface disposed toward the fuel and air source; and
 wherein the flame holder is configured to receive mixed fuel and air at the proximal surface of the flame holder when the flame holder is disposed at the distal working position.   
     
     
         50 .- 70 . (canceled) 
     
     
         71 . A burner, comprising:
 a body defining a combustion chamber having a main axis;   a plurality of bearing surfaces operatively coupled to the body; and   a flame holder disposed in the combustion chamber and supported by the plurality of bearing surfaces, the flame holder including:
 a distal surface; 
 a proximal surface; and 
 a plurality of perforations extending between the distal and proximal surfaces, the plurality of bearing surfaces being configured to selectively support the flame holder at a plurality of positions within the combustion chamber. 
   
     
     
         72 . The burner of  claim 71 , wherein the bearing surface includes rolling cylinders or balls. 
     
     
         73 . The burner of  claim 71 , wherein the bearing surface includes rails.