Perforated Flame Holder Combustion Stability and NOx Reduction
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Solution Overview
Problem
Conventional flame holders struggle to sustain combustion with lean fuel-to-oxidant mixtures and fail to effectively reduce oxides of nitrogen (NOx) emissions, as they cannot maintain stable combustion reactions at lower temperatures.
Innovation Solution
A horizontally-fired burner system incorporating a perforated flame holder with a heating mechanism that preheats the flame holder before fuel injection, causing combustion reactions to occur primarily within the perforations, which radiates heat to adjacent catalysts and limits NOx formation by containing reactions and reducing peak temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional flame holders are used to sustain combustion, then combustion can occur, but stable combustion reactions cannot be maintained at lower temperatures and lean fuel-to-oxidant mixtures cannot be sustained
Solution Approach 1:
The flame holder is constructed with a porous structure that allows fuel and oxidant to percolate through the material. This porous configuration enables combustion to occur throughout the volume of the flame holder rather than at a single point, distributing the heat and maintaining stable combustion at lower temperatures while supporting lean fuel-to-oxidant mixtures.
2Object-generated harmful factors
If conventional flame holders are used, then combustion can be sustained, but oxides of nitrogen (NOx) emissions cannot be effectively reduced
Solution Approach 1:
The porous flame holder structure changes the physical parameters of combustion by increasing the surface area for reaction and distributing the combustion zone. This parameter change allows combustion to occur at lower peak temperatures, which directly reduces thermal NOx formation while maintaining sustainable combustion through the distributed reaction zones throughout the porous material.
3Object-generated harmful factors
If combustion reactions are confined to limited spaces, then NOx formation is reduced, but the combustion reaction may become unstable
Solution Approach 1:
The porous structure provides numerous interconnected channels and surfaces throughout the flame holder volume, creating multiple distributed combustion zones. This distributed architecture maintains reaction stability by providing continuous pathways for fuel and oxidant while confining the combustion reactions to the porous material structure, thereby reducing NOx formation without sacrificing combustion stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves stable combustion with leaner fuel-to-oxidant mixtures and significantly reduces NOx emissions by confining combustion reactions within the perforated flame holder, maintaining reaction stability and minimizing exposure to high temperatures.
Implementation Method 1
A heating mechanism is positioned adjacent the perforated flame holder. In one embodiment the heating mechanism applies heat to the perforated flame holder before the fuel nozzle outputs fuel onto the perforated flame holder.
Implementation Method 2
The elevated temperature of the perforated flame holder causes a combustion reaction of the fuel within the perforations of the flame holder.
Implementation Method 3
Heat from the combustion reaction radiates from the flame holder and heats the tube, thereby causing the reactant to react with the catalyst.
Implementation Method 4
Heat from the combustion reaction radiates from the flame holder and heats the tube, thereby causing the reactant to react with the catalyst.
Data Source
AI summary
A horizontally-fired flame burner includes a flame holder positioned laterally from the burner. The flame holder includes a plurality of perforations that collectively confine a combustion reaction of the burner to the flame holder.