Furnace Burner Radiation Shield for Low-NOx Heat Control
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Solution Overview
Problem
Central furnaces with premix burners experience high heat transfer to the center panel and heat exchanger crimps, leading to unacceptable surface temperatures and reduced functional life due to uneven combustion product flow and heat output in multiple parallel heat exchanger paths.
Innovation Solution
A burner system incorporating a radiation shield with a thermal barrier coating and a refractory material, designed to reduce heat transfer, combined with flue gas recirculation and a FeCrAl alloy fiber burner head, which can withstand high temperatures and evenly distribute the gas and air mixture to minimize NOx emissions and optimize combustion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a premix burner is used to reduce NOx emissions, then emissions are reduced, but heat transfer to the center panel and heat exchanger crimps increases leading to unacceptable surface temperatures
Solution Approach 1:
A radiation shield is introduced as an intermediary component between the premix burner and the heat exchanger center panel. The shield intercepts radiant heat from the flame and redirects it away from the center panel, thereby reducing the harmful heat transfer to this specific area while preserving the low NOx emissions benefit of the premix burner
2Temperature
If a radiation shield is added to reduce heat transfer to the center panel, then surface temperature is reduced, but device complexity increases
Solution Approach 1:
The radiation shield is designed to provide localized thermal protection only to the center panel area that requires it, rather than shielding the entire heat exchanger. This targeted approach reduces heat transfer to the critical area while minimizing the added complexity and cost of the shielding system
3Productivity
If multiple parallel heat exchanger paths are used to increase heat output, then heat output is increased, but uneven combustion product flow and heat distribution occur
Solution Approach 1:
The radiation shield is designed with multiple sections or openings that correspond to the parallel heat exchanger paths. This segmentation allows combustion products to flow evenly through each path while the shield portions redirect radiant heat away from the center panel, maintaining uniform heat distribution across all paths
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 solution effectively reduces operating temperatures by up to 600 degrees Fahrenheit, extends the life of heat exchanger components, and achieves low NOx emissions while maintaining combustion efficiency across multiple parallel heat exchanger paths.
Implementation Method 1
A burner system incorporating a radiation shield with a thermal barrier coating and a refractory material, designed to reduce heat transfer
Implementation Method 2
A burner system incorporating a radiation shield with a thermal barrier coating and a refractory material, designed to reduce heat transfer
Implementation Method 3
A burner system incorporating a radiation shield with a thermal barrier coating and a refractory material, designed to reduce heat transfer
Implementation Method 4
achieves low NOx emissions while maintaining combustion efficiency
Data Source
AI summary
A burner system for a furnace. The system may have a wedged or other shaped burner box. An air-fuel mixer may be attached to a smaller end of the burner box at virtually any angle relative to a direction of a gas and air mixture leaving the larger box end. A burner head may be attached to the larger end of the box. The burner head may be sufficient for numerous heater sections of a heat exchanger. A spacer and a radiation shield may be situated between the burner head and heat exchanger. An addition of the radiation shield may reduce the operating temperature of the burner box, burner head and/or spacer. A fan may move the gas and air mixture from the mixer, through the box and the burner head. The mixture may be ignited into a flame which is moved into the heat exchanger.