Pilot Stabilized Burner Low NOx Combustion
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Solution Overview
Problem
Existing burner systems face challenges in achieving low emissions, particularly in reducing NOx output, while maintaining efficient combustion and stability of the flame, especially in industrial furnace applications.
Innovation Solution
The implementation of a pilot burner and a distal flame holder configuration, where the pilot burner supports a pilot flame that ignites and sustains a main fuel nozzle, with the distal flame holder positioned to hold and stabilize the main flame, utilizing a perforated flame holder to contain the combustion reaction and minimize NOx emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a conventional burner system is used, then combustion can be maintained, but NOx emissions increase
Solution Approach 1:
The burner system is segmented into distinct functional zones: a primary combustion zone with the fuel nozzle, a secondary combustion zone with the pilot burner, and a distal flame holder zone. This spatial segmentation allows different combustion stages to occur under optimized conditions, reducing NOx while maintaining efficiency
Solution Approach 2:
The pilot burner provides preliminary heating and pre-ignition of the main fuel stream before it reaches the distal flame holder. This preliminary action ensures that the main fuel is already partially combusted or heated when it enters the flame holder, reducing peak temperatures and NOx formation while maintaining stable combustion
Solution Approach 3:
The distal flame holder acts as an intermediary component between the fuel nozzle and the pilot burner. It mediates the combustion process by providing a controlled environment where the main fuel can be ignited and stabilized, preventing direct contact between high-energy flame and cooler zones that would cause instability
2Reliability
If the pilot burner is positioned close to the distal flame holder, then ignition is facilitated, but flame stability decreases
Solution Approach 1:
The system creates different thermal and compositional zones at different locations: the pilot burner zone provides localized heating, the distal flame holder zone provides stable combustion, and the intermediate zone allows for controlled transition. This local differentiation allows close positioning for ignition reliability while maintaining overall flame stability through zone-specific conditions
3Object-generated harmful factors
If additional emission control measures like SCR or water/steam injection are added, then NOx emissions decrease, but device complexity increases
Solution Approach 1:
The burner system uses its own combustion process to control emissions. The pilot burner and distal flame holder configuration creates self-regulating temperature zones and combustion stages that inherently reduce NOx formation, eliminating the need for external SCR or water/steam injection systems
Solution Approach 2:
The invention extracts and eliminates the need for complex post-combustion emission control systems like SCR or water/steam injection by addressing NOx formation at the combustion source itself through the pilot burner and distal flame holder configuration
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
This configuration achieves low NOx emissions of about twenty parts per million or less, with stable combustion and efficient heat output, without the need for additional emission control measures like SCR or water/steam injection, and maintains combustion stability across varying conditions.
Implementation Method 1
The pilot burner is configured to support a pilot flame to heat the distal flame holder
Implementation Method 2
The distal flame holder is configured to hold at least a portion of a combustion reaction supported by the main fuel
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
According to an embodiment, a burner system includes a pilot burner disposed in a furnace at a distal position along a main fuel and combustion air flow axis, and one or more main fuel nozzles disposed at a proximal position along the main fuel and combustion air flow axis. The pilot burner is configured to support a pilot flame and the one or more main fuel nozzles are configured to support a main flame in contact with the pilot flame. The pilot burner is disposed to cause the main fuel and combustion air to be ignited by the pilot flame.