Spread Flame Burner Orifice Angles for Steel Reheating
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Solution Overview
Problem
The existing spread flame burners in heat treatment furnaces for reheating steel products suffer from temperature heterogeneity and increased NOx emissions due to the shape of the tunnel, which limits the aspiration of ambient smoke and leads to local overheating, necessitating an improvement in heat flux distribution and pollutant reduction.
Innovation Solution
A new spread flame burner design with optimized fuel and oxidizer injection angles and recirculation of combustion products to extend the reaction volume, slow down fuel oxidation, and reduce NOx emissions, featuring a combination of fuel and oxidizer orifices with specific inclination angles and diameters to control the mixing and convergence of jets, thereby achieving better heat transfer and reduced pollutant production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the tunnel shape is used to limit aspiration of ambient fumes, then the burner structure is simplified, but local overheating occurs and NOx emissions increase
Solution Approach 1:
The burner is divided into multiple independent orifices (fuel orifices and oxidizer orifices) arranged in specific patterns. The fuel injection system and oxidizer injection system are segmented into separate components that can be independently controlled, allowing precise management of combustion zones to prevent local overheating and reduce NOx emissions while maintaining structural simplicity.
Solution Approach 2:
Different regions of the burner are designed with different properties: fuel orifices are positioned and sized to create specific jet patterns, while oxidizer orifices are arranged to provide localized cooling and dilution in high-temperature zones. This local differentiation allows the burner to maintain overall simplicity while addressing the harmful effects of local overheating through targeted design features in specific areas.
2Use of energy by moving object
If fuel and oxidizer are injected with high velocity to improve combustion efficiency, then energy utilization improves, but temperature heterogeneity in products increases
Solution Approach 1:
The burner design carefully controls injection parameters including velocity, angle, and timing of fuel and oxidizer. By optimizing these parameters, the system achieves efficient combustion while the specific geometric arrangement of orifices and injection angles ensures that heat is distributed more uniformly across the product surface, reducing temperature heterogeneity even at high combustion efficiency.
Solution Approach 2:
Recirculated combustion products serve as an intermediary medium that mediates between the high-velocity fuel-oxidizer reaction and the product surface. This recirculated gas acts as a heat transfer medium that distributes thermal energy more uniformly, reducing temperature heterogeneity while maintaining combustion efficiency through controlled recirculation rates and patterns.
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 improved burner design achieves enhanced temperature homogeneity and significantly reduces NOx emissions, meeting stringent regulatory standards while maintaining the benefits of the spread flame technology, such as reduced furnace height and lower construction costs.
Implementation Method 1
recirculation of combustion products to extend the reaction volume, slow down fuel oxidation, and reduce NOx emissions
Implementation Method 2
dilute reactants and expand the reaction volume
Implementation Method 3
combination of fuel and oxidizer orifices with specific inclination angles and diameters to control the mixing and convergence of jets
Implementation Method 4
control the mixing and convergence of jets
Implementation Method 5
slow down fuel oxidation, and reduce NOx emissions
Implementation Method 6
achieves enhanced temperature homogeneity and significantly reduces NOx emissions
Data Source
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AI summary
Burner for an oven for reheating siderurlogical products such as billets, blooms or slabs, or for heat treatment oven, which is equipped with a fuel injection device and with an oxidant feed body feeding feed orifices with oxidant, the burner having an axial direction; the injection device is designed to provide a central injection of fuel via an orifice in, or parallel to, the axial direction of the burner; the oxidant feed body includes two sets of four oxidant feed orifices, each set including two orifices situated above a horizontal plane passing through the axial direction of the burner, and two orifices situated below this plane, the orifices of a second set being further away from the horizontal plane than those of the first set, the geometric axes of the orifices of the two sets making angles of inclination with respect to the axial direction of the burner.