Dual-Jacket Combustion Chamber for Gas Heat Exchanger Emission Control
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Solution Overview
Problem
Existing combustion chambers in gas-fired heat exchangers face challenges in achieving efficient combustion and cooling while maintaining low emissions of carbon monoxide and nitrogen oxides, particularly with modulating burner systems, where there is a conflict between these goals.
Innovation Solution
A combustion chamber design featuring an inner and outer jacket with a perforated wall made of high-temperature resistant material, allowing for controlled gas-air mixture pumping and cooling, which contains the flame area within the chamber and effectively cools the chamber through the flowing mixture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the combustion chamber is thermally insulated, then heat transfer efficiency is improved, but combustion temperature control and emission reduction are worsened
Solution Approach 1:
The combustion chamber is divided into two separate chambers: a first combustion chamber for primary combustion and a second combustion chamber for secondary combustion. This segmentation allows different thermal management strategies in each chamber, enabling efficient heat transfer in the first chamber while providing emission reduction through secondary combustion in the second chamber.
Solution Approach 2:
A heat exchanger is introduced as an intermediary component between the two combustion chambers. It transfers heat from the first combustion chamber to the second combustion chamber, enabling thermal coupling between the chambers while maintaining their functional independence for different combustion stages.
2Adaptability or versatility
If a modulating burner system is used, then combustion flexibility is improved, but emission control becomes more difficult
Solution Approach 1:
The dual-chamber combustion system ensures continuous and complete combustion across different operating conditions. The first chamber handles primary combustion while the second chamber ensures complete combustion of remaining gases, maintaining low emissions regardless of the modulating burner's output level.
Solution Approach 2:
By separating combustion into two stages in different chambers, the system can independently optimize each combustion phase. This segmentation allows the modulating burner to vary fuel input while the second chamber consistently completes combustion, maintaining emission control across the full modulation range.
3Productivity
If the flame area is contained within the combustion chamber, then combustion efficiency is improved, but heat transfer to the heat exchanger is reduced
Solution Approach 1:
The heat exchanger acts as an intermediary that captures heat from the first combustion chamber while allowing the combustion process to continue in the second chamber. This enables efficient heat transfer without compromising combustion completion.
Solution Approach 2:
The combustion system is segmented into two chambers with different functions: the first chamber optimizes combustion efficiency with contained flame, while the second chamber handles emission reduction. The heat exchanger is positioned to extract heat from the first chamber without interfering with the combustion containment.
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 design enables precise control of burning parameters, including flame size, and efficiently cools the combustion chamber, reducing emissions while maintaining effective heat transfer to the heat exchanger.
Implementation Method 1
the gas and cold air pumped into the space between the outer and inner jackets cool the combustion chamber adequately while flowing around the inner jacket
Implementation Method 2
the mixture pumped into the space 3 between the outer jacket 1 and inner jacket 2 cools the inner jacket 2 and outer jacket 1 of the combustion chamber when flowing around the inner jacket 2, whereas the hot combustion gases get into the fuel exchanger sub-assembly 7
Data Source
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AI summary
A combustion chamber for a gas-fired heat exchanger according to the invention, open on one side and fitted with a burner, is characterised in that there is a space (3) formed between its inner jacket (2) and its outer jacket (1) to accommodate the mixture of gas and air supplied to the burner (4), where the latter is fitted with a perforated wall (5) and where there is a ventilator (6) and a gas valve mounted in the outer jacket (1). Preferably, the perforated wall (5) of the burner (4) is made of a material resistant to high temperatures, preferably a perforated steel sheet and/or mesh and/or a woven and/or non-woven material.