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US 9,562,682 B2Granted
Burner with a series of fuel gas ejectors and a perforated flame holder
AssigneeClearsign Combustion Corporation
InventorsDouglas W. Karkow, Robert Breidenthal, Joseph Colannino, Christopher A. Wiklof
Life of this patent
Estimating the term…
Abstract
A combustion system outputs fuel gas from a plurality of fuel ejectors toward a forward end of a burner wall and preheats a perforated flame holder by sustaining combustion reaction of the fuel gas at combustion zone between the burner wall and a perforated flame holder. The combustion system then outputs fuel gas from the fuel ejectors onto the perforated flame holder and sustains a combustion reaction of the fuel gas within the perforated flame holder.
Claims20
A burner providing reduced NOx emissions comprising:
- a burner wall having a forward end;
- at least one first fuel gas nozzle positioned longitudinally rearward of and laterally outward from the forward end of the burner wall;
- at least one fuel gas delivery port positioned in the first fuel gas nozzle to deliver fuel gas in a flow path outside of the burner wall to a combustion zone at the forward end of the burner wall;
- at least one exterior ledge provided on the burner wall and positioned between the fuel gas delivery port and the forward end of the burner wall such that at least a portion of the fuel gas traveling in the flow path will contact the exterior ledge, the exterior ledge being spaced apart from the forward end;
- and
- a perforated flame holder including:
- an input face proximal to the front end of the burner wall;
- an output face distal from the burner;
- and
- a plurality of perforations extending between the input and output faces;
- wherein the burner wall and the at least one first fuel gas nozzle are configured to preheat the perforated flame holder to a threshold temperature by supporting a first combustion reaction in the combustion zone;
- and further comprising
- at least one second fuel gas nozzle configured to output fuel gas onto the perforated flame holder after the perforated flame holder has been heated to the threshold temperature;
- and further comprising
- a control circuit operatively coupled to the at least one first fuel gas nozzle and the at least one second fuel gas nozzle;
- wherein the control circuit is configured to:
- cause the at least one first fuel gas nozzle to output fuel gas toward the forward end of the burner wall during a preheating phase;
- terminate the preheating phase after the perforated flame holder has reached a threshold temperature;
- and
- cause the at least one second fuel gas nozzle to output fuel gas onto the perforated flame holder after the preheating phase has been terminated.
17 more elements
A burner providing reduced NOx emissions for use in a heating system having a flue gas therein, the burner comprising:
- a burner wall having a forward end;
- a series of first fuel gas ejectors, each having only a single fuel gas ejection port provided therein, the first fuel gas ejectors and the single fuel gas ejection ports provided therein being positioned and the fuel gas ejection ports being configured to deliver fuel gas from the first fuel gas ejectors in a plurality of adjacent free jet flow streams outside of the burner wall toward a combustion zone at the forward end of the burner wall, each of the adjacent free jet flow streams being effective for entraining a portion of the flue gas in the fuel gas and the fuel gas ejection ports being positioned longitudinally rearward and laterally outward with respect to the forward end of the burner wall;
- an impact structure positioned between the fuel gas ejection ports and the forward end of the burner wall such that the impact structure will be contacted by at least a portion of the fuel gas traveling in the flow streams;
- and
- a perforated flame holder including:
- an input face proximal to the front end of the burner wall;
- an output face distal from the burner;
- and
- a plurality of perforations extending between the input and output faces;
- wherein the burner wall and the first fuel gas ejectors are configured to preheat the perforated flame holder to a threshold temperature by supporting a first combustion reaction in the combustion zone;
- and further comprising
- at least one second fuel gas ejector configured to output fuel gas onto the perforated flame holder after the perforated flame holder has been heated to the threshold temperature;
- and
- a control circuit operatively coupled to the first fuel gas ejectors and the at least one second fuel gas ejector;
- wherein the control circuit is configured to:
- cause the first fuel gas ejectors to output fuel gas toward the forward end of the burner wall during a preheating phase;
- terminate the preheating phase after the perforated flame holder has reached a threshold temperature;
- and
- cause the at least one second fuel gas ejector to output fuel gas onto the perforated flame holder after the preheating phase has been terminated.
16 more elements
A method comprising:
- preheating a perforated flame holder to a threshold temperature by:
- ejecting fuel gas outside of a burner wall of the burner in free jet flow such that at least a portion of flue gas is entrained in said fuel gas and said fuel gas travels outside of said burner wall to a combustion zone having a beginning end substantially at said forward end of said burner wall;
- delivering an oxidant to the combustion zone via an interior passageway of the burner with an outlet at the forward end of the burner;
- and
- supporting a first combustion reaction of the fuel gas and the oxidant in the combustion zone between the forward end of the burner and the perforated flame holder;
- terminating the preheating of the perforated flame holder after the perforated flame holder has reached the threshold temperature;
- ejecting fuel gas onto the perforated flame holder;
- delivering the oxidant to the perforated flame holder via the interior passageway;
- and
- supporting a second combustion reaction of the fuel gas and the oxidant within the perforated flame holder;
- wherein the step of ejecting fuel gas outside of the burner wall of the burner in free jet flow further comprises ejecting the fuel gas from at least one first fuel gas ejector;
- wherein the step of ejecting fuel gas onto the perforated flame holder further comprises ejecting the fuel gas from at least one second fuel gas ejector configured to output fuel gas onto the perforated flame holder after the perforated flame holder has been heated to the threshold temperature;
- and further comprising
- causing the at least one first fuel gas ejector to output fuel gas toward the forward end of the burner wall during a preheating phase;
- and
- causing the at least one second fuel gas ejector to carry out the step of ejecting fuel gas onto the perforated flame holder after the preheating has been terminated.
13 more elements
Dependencies are inferred from the claim text.