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US 2017/0010019 A1Published application
LOW NOx FIRE TUBE BOILER
AssigneeClearsign Combustion Corporation
InventorsDOUGLAS W. KARKOW, JOSEPH COLANNINO, IGOR A. KRICHTAFOVITCH, ROBERT E. BREIDENTHAL, CHRISTOPHER A. WIKLOF
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Abstract
A fire tube boiler includes a perforated flame holder configured to hold a combustion reaction that produces very low oxides of nitrogen (NOx).
Claims45
A low oxides of nitrogen (NOx) fire tube boiler, comprising:
- a shell configured to hold water;
- at least one combustion pipe disposed at least partially inside the shell, the combustion pipe being characterized by a length and an inside diameter, the combustion pipe surrounding a combustion volume and structured to hold the water out of the combustion volume;
- a fuel nozzle disposed to output a fuel jet into the combustion volume defined by the combustion pipe;
- an air source disposed to output combustion air into the combustion volume;
- and
- a perforated flame holder disposed in the combustion pipe, the perforated flame holder being aligned to receive the fuel jet and combustion air from the fuel nozzle and air source;
- wherein the perforated flame holder includes a body that defines a plurality of void volumes operable to convey the fuel and air and to hold a combustion reaction supported by the fuel and air, the body further being configured to receive heat from the combustion reaction in the void volumes, hold the heat, and output the heat to the fuel and air in the void volumes to maintain combustion of a lean fuel and air mixture.
4 more elements
A method for operating a low oxides of nitrogen (NOx) fire tube boiler, comprising:
- providing a boiler shell including at least one combustion pipe disposed at least partially inside the shell and a plurality of fire tubes disposed inside the shell, the plurality of fire tubes being configured to receive combustion products from the combustion pipe, the combustion pipe being characterized by a length and an inside diameter, the boiler shell being structured to hold boiler water, the combustion pipe surrounding a combustion volume and forming a continuous volume with the plurality of fire tubes, and the combustion pipe and fire tubes being configured to collectively hold the boiler water out of the combustion volume;
- providing a perforated flame holder including a body that defines a plurality of void volumes operable to convey the fuel and air and to hold a combustion reaction;
- supporting the perforated flame holder in the combustion pipe;
- outputting fuel and combustion air into the combustion volume in a direction aligned to deliver mixed fuel and combustion air to the perforated flame holder;
- holding a combustion reaction supported by the fuel and combustion air with the perforated flame holder;
- delivering hot combustion products to the fire tubes;
- transferring heat from the fire tubes to the boiler water;
- outputting hot water or steam from the boiler;
- and
- outputting combustion products including less than 10 parts per million NOx at 3% excess oxygen.
7 more elements
Dependencies are inferred from the claim text.