Dual Perforated Flame Holders for Stable Complete Combustion
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Solution Overview
Problem
Existing combustion systems face challenges in maintaining stable combustion reactions, particularly when high fuel and oxidant flow rates or thermal loads exceed the autoignition temperature of the first perforated flame holder, leading to incomplete combustion and the production of intermediate combustion products.
Innovation Solution
A dual-perforated flame holder system where the second flame holder supports combustion reactions of incompletely combusted products from the first, ensuring complete combustion by preheating and receiving combustion products to maintain stable combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the flow rate of fuel and oxidant is increased to meet high thermal load demands, then the combustion system can handle higher thermal loads, but the fuel may not have time to reach its autoignition temperature inside the first perforated flame holder, resulting in incomplete combustion
Solution Approach 1:
The combustion system is divided into two separate perforated flame holders, each serving distinct functions. The first flame holder handles initial combustion at lower flow rates, while the second flame holder takes over when flow rates exceed the autoignition capability of the first holder. This segmentation allows the system to maintain reliable combustion across a wider range of thermal loads.
Solution Approach 2:
The second perforated flame holder acts as an intermediary component that receives incompletely combusted products from the first flame holder and completes the combustion process. This intermediary structure ensures that even when the first flame holder cannot fully combust the fuel due to high flow rates, the combustion process can still be completed, maintaining overall system reliability.
2Device complexity
If a single perforated flame holder is used to maintain simple system structure, then the device complexity is reduced, but the system cannot ensure complete combustion under varying flow conditions
Solution Approach 1:
Instead of using a single complex flame holder design that would need to handle all combustion conditions, the system segments the combustion function across two simpler flame holders. Each flame holder can be optimized for its specific function, and together they achieve complete combustion under varying conditions without requiring excessive complexity in any single component.
3Device complexity
If the first perforated flame holder operates alone to reduce device complexity, then the system is simpler, but NOx emissions cannot be reduced to low single-digit ppm concentrations
Solution Approach 1:
The two-flame holder configuration segments the combustion process to achieve better emission control. The first flame holder performs initial combustion, and the second flame holder completes the combustion of intermediate products. This segmented approach ensures more complete combustion and reduces NOx emissions to low single-digit ppm concentrations without requiring additional complex emission treatment systems.
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 complete or more complete combustion of fuel and oxidant, reducing NOx emissions to low single-digit ppm concentrations without additional treatment methods, and maintaining stable combustion across varying conditions.
Implementation Method 1
The second perforated flame holder transfers heat to the first perforated flame holder. As the flow of fuel and oxidant passes through or adjacent to the first perforated flame holder, the first perforated flame holder heats the flow of fuel and oxidant.
Implementation Method 2
Preheating the flow of fuel and oxidant in this manner can enhance the ability of the second perforated flame holder to stably support a combustion reaction of the flow of fuel and oxidant
Implementation Method 3
The first perforated flame holder holds a combustion reaction of the fuel and oxidant. The second perforated flame holder holds a combustion reaction of a portion of the flow of fuel and oxidant and the incompletely combusted combustion products.
Implementation Method 4
the first perforated flame holder may react methane and oxygen to produce carbon monoxide and hydrogen or carbon monoxide and water. the carbon monoxide may be fully oxidized to carbon dioxide
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A combustion system includes a fuel and oxidant source, a first perforated flame holder, a second perforated flame holder, and a thermal load. The fuel and oxidant source outputs fuel and oxidant. The first and second perforated flame holders simultaneously or alternately hold combustion reactions of the fuel and oxidant and/or of combustion products. The thermal load receives thermal energy from the first and second combustion reactions.