Asymmetric Burner Lance Positioning for Uniform Combustion
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Solution Overview
Problem
Existing burner assemblies in industrial furnaces experience non-uniform temperature profiles, leading to thermal stress and increased NOx emissions due to hot-spots, which result in inconsistent product quality, particularly in pellet induration processes.
Innovation Solution
The burner lance is repositioned to have a smaller distance to the combustion chamber centerline, with a specific velocity ratio and inclination, inducing flame deflection and recirculation, which modifies the gas flow and temperature distribution, reducing temperature gradients and NOx formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the burner lance is positioned at the centerline of the combustion chamber, then the combustion process is stable and easy to control, but a non-uniform temperature profile is created with hot-spots leading to thermal stress and increased NOx emissions
Solution Approach 1:
The burner lance is deliberately positioned asymmetrically relative to the combustion chamber centerline, specifically at a distance of 0.05D to 0.15D from the centerline. This asymmetric positioning creates a more uniform temperature distribution by preventing the formation of concentrated hot-spots that occur with centered positioning, thereby reducing thermal stress on chamber walls and decreasing NOx emissions from localized high-temperature zones
2Object-generated harmful factors
If the burner lance is repositioned to achieve more uniform temperature distribution, then thermal stress and NOx emissions are reduced, but the combustion configuration becomes more complex
Solution Approach 1:
The invention achieves uniform temperature distribution by changing the positional parameter of the burner lace from the centerline to a specific offset distance (0.05D to 0.15D from centerline). This simple parameter modification, rather than redesigning the entire burner system, reduces thermal stress and NOx emissions while maintaining relatively simple device configuration
3Device complexity
If secondary oxidant is introduced via a vertical downcomer, then the combustion chamber structure is simple, but large temperature gradients are created across the furnace width
Solution Approach 1:
The burner lance is positioned asymmetrically at 0.05D to 0.15D from the centerline, which modifies the interaction between the fuel-oxidant mixture and the secondary oxidant from the vertical downcomer. This asymmetric configuration promotes better mixing and reduces the large temperature gradients that would otherwise occur across the furnace width, achieving more uniform temperature distribution while maintaining simple structural design
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 a more uniform temperature profile across the furnace, reducing thermal stress and NOx emissions, and enhances pellet quality by creating a swirl effect that improves mixing and temperature homogeneity.
Implementation Method 1
combustion of gaseous or liquid fuel in a combustion chamber which can have a cylindrical shape with a sectional diameter D whereby gaseous or liquid fuel as well as primary oxidant with a mean velocity of u1 is introduced via a burner lance (including a nozzle head) into the combustion chamber
Implementation Method 2
The burner lance is repositioned to have a smaller distance to the combustion chamber centerline, with a specific velocity ratio and inclination, inducing flame deflection and recirculation, which modifies the gas flow and temperature distribution
Implementation Method 3
enhances pellet quality by creating a swirl effect that improves mixing and temperature homogeneity
Implementation Method 4
a non-uniform temperature profile leads to thermal stress on the wall of the combustion chamber
Implementation Method 5
hot-spots in the flame will increase the formation of NOx
Data Source
AI summary
A method and apparatus for combustion of fuel in a combustion chamber with a hydraulic diameter D. Fuel and a primary oxidant are introduced via a burner lance into the combustion chamber, having a certain mean velocity u1 at entry, and a secondary oxidant with a mean velocity of u2 is introduced into the combustion chamber. The burner lance has a position p that has a distance Id1I defined as the smallest distance between p and a combustion chamber centerline.