Heating Element Stabilizes Flameless Combustion in Cooled-Wall Chambers
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Solution Overview
Problem
Flameless combustion stabilization is challenging in 'cold wall' combustion enclosures due to the cooling of combustion products upon contact with walls, which prevents self-ignition and limits the application of flameless oxidation technologies typically used in high-temperature processes.
Innovation Solution
A device with a heating element positioned in the burner zone to heat combustion products before they mix with oxidizer and fuel, ensuring self-ignition conditions are maintained, combined with an air preheating system using radiative flux recovery to enhance stability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If flameless combustion is used to reduce nitrogen oxide emissions, then nitrogen oxide emissions are reduced, but combustion stability is lost in cold wall enclosures
Solution Approach 1:
The combustion chamber is divided into distinct zones: a preheating zone where combustion products are heated by the heating element, and a combustion zone where diluted combustion occurs. This segmentation allows the preheating zone to provide stable ignition conditions while the combustion zone maintains low emissions, resolving the contradiction between stability and emission reduction.
Solution Approach 2:
A heating element acts as an intermediary device that preheats the combustion products before they enter the combustion zone. This intermediary heating mechanism provides the necessary temperature for stable combustion without requiring the entire chamber to be at high temperature, thus maintaining combustion stability while enabling flameless combustion for emission reduction.
2Temperature
If combustion products are cooled by cold walls, then wall temperatures are kept low, but self-ignition conditions cannot be achieved
Solution Approach 1:
The heating element performs preliminary heating of the combustion products before they reach the combustion zone. This preliminary action ensures that the combustion products achieve the necessary temperature for self-ignition without requiring the walls to be hot, thus maintaining low wall temperatures while enabling self-ignition capability.
Solution Approach 2:
The heating element creates a localized high-temperature zone around the combustion products without heating the walls. This local quality approach allows self-ignition to occur in the combustion zone while the walls remain cold, resolving the contradiction between wall temperature and self-ignition capability.
3Object-generated harmful factors
If external recirculation of combustion products is used to reduce oxygen concentration, then thermal nitrogen oxides are reduced, but device complexity increases
Solution Approach 1:
The invention extracts the recirculation function from a complex external system and integrates it into the burner design itself. The combustion products are recirculated through the burner structure, eliminating the need for separate external recirculation equipment while still achieving oxygen concentration reduction and thermal nitrogen oxide reduction.
Solution Approach 2:
The heating element and recirculation system are merged into a single integrated component within the burner. This combination achieves both the thermal processing of combustion products and their recirculation function simultaneously, reducing device complexity while maintaining the ability to reduce thermal nitrogen oxides.
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
Achieves stable, highly diluted combustion with reduced nitrogen oxide and carbon monoxide emissions, homogeneous heat transfer, and lower temperature peaks, while minimizing thermo-acoustic instabilities and maintaining low wall temperatures.
Implementation Method 1
said heating element being positioned in the zone of dilution and surrounding all of the oxidizer and fuel jets
Implementation Method 2
an air preheating system using radiative flux recovery
Implementation Method 3
intense dilution of the oxidizer and fuel jets via internal recirculations of combustion products themselves
Implementation Method 4
internal recirculations of the combustion products towards the burner zone
Implementation Method 5
an air preheating system using radiative flux recovery to enhance stability and efficiency
Implementation Method 6
combustion technologies with high energy and environmental efficiency for combustion enclosures
Data Source
Figure 1~2
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AI summary
The device for stabilizing dilute combustion which is intended to be used in a combustion chamber (245) said to be of the cooled-walls type, equipped with a burner comprising at least one oxidant inlet (205) and at least one fuel inlet (210), the oxidant and fuel inlets opening separately into the chamber at a distance suited to the setting-up of combustion (240) which is highly diluted by internal recirculations (220) of the products of combustion towards the burner region, which device comprises a heating element (215) designed to reheat, during steady operating conditions, the products of combustion in order to sustain self-ignition conditions, said heating element being positioned in the dilutions region and surrounding the set of oxidant and fuel jets (295).