Furnace Oxygen Lancing for Heat Distribution and NOx Reduction
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Solution Overview
Problem
Industrial furnaces using air as an oxidant face inefficiencies in heat distribution and high NOx production, with oxyfuel burners being costly and difficult to maintain uniformity in large furnaces, and increasing oxygen in air supply causing additional issues.
Innovation Solution
Introducing a lance to inject high-velocity oxygen gas into the furnace, impinging it on the burner flame, with at least 50% of oxygen supplied through the lance to achieve stoichiometric balance and reduce NOx production, while maintaining uniform heat distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If air is used as oxidant in conventional burners, then the furnace can operate with simple equipment, but heat distribution uniformity deteriorates and NOx production increases
Solution Approach 1:
The oxidant supply is segmented into two separate systems: (1) a conventional burner oxidant supply and (2) a separate lance-based oxidant injection system. This segmentation allows independent optimization of each system - the burner provides base heating while the lance delivers concentrated oxygen to specific zones, improving heat distribution uniformity without requiring complete replacement of the conventional burner system
Solution Approach 2:
The lance acts as an intermediary device that bridges the conventional burner system and the oxidant supply. By injecting oxygen through the lance at specific locations and angles, it mediates the combustion process to achieve better temperature distribution and reduce NOx formation, while maintaining compatibility with existing burner infrastructure
2Productivity
If oxygen gas is lanced into the furnace to improve heat distribution and reduce NOx, then combustion efficiency improves, but device complexity increases
Solution Approach 1:
The lance system is designed to perform multiple functions: (1) inject oxygen to enhance combustion efficiency, (2) improve heat distribution uniformity, (3) reduce NOx production, and (4) work with existing conventional burners. This multi-functionality justifies the added complexity by delivering multiple benefits from a single device addition
Solution Approach 2:
The lance system incorporates adjustable parameters including injection angle, injection velocity, and oxygen flow rate. These dynamic adjustments allow optimization of combustion efficiency while managing system complexity through flexible control rather than fixed rigid design
3Object-generated harmful factors
If oxyfuel burners are used to reduce NOx and improve efficiency, then NOx production decreases, but cost increases substantially
Solution Approach 1:
The invention extracts only the essential oxygen-injection function from the expensive oxyfuel burner system and implements it through a simpler lance-based approach. By separating the oxygen injection function from the complete oxyfuel burner replacement, it achieves NOx reduction and efficiency improvement without the substantial cost of full oxyfuel burner conversion
Solution Approach 2:
The lance system represents a cost-effective, simpler alternative to expensive oxyfuel burners. It uses readily available components (lance, oxygen supply) rather than requiring costly specialized burners, making it an economical solution for reducing NOx while maintaining acceptable performance
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 method enhances heat distribution uniformity and significantly reduces NOx production in combustion products, improving furnace efficiency and reducing fuel consumption, while being cost-effective and applicable to large furnaces.
Implementation Method 1
An oxidant in the form of oxygen gas is introduced into the furnace through the lance and impinges onto the flame of the burner at a certain point
Implementation Method 2
The oxidant is fed into the furnace through the lance at a velocity of at least 200 m/s
Implementation Method 3
at least one lance is introduced into the furnace. An oxidant in the form of oxygen gas is introduced into the furnace through the lance
Implementation Method 4
the convective heat transfer within the furnace becomes less effective as the volume of the furnace increases
Data Source
AI summary
A method for providing uniform heat distribution within a furnace as well as decreasing the amount of NOx in the combustion products, when operating an industrial furnace having at least one conventional burner using air as the oxidant. At least one lance is connected with the furnace, and an oxidant including oxygen gas is flowed into the furnace through the lance to impinge against a flame issuing from the burner at a certain impingement point. The amount of oxygen supplied by the air supply to the burner together with the amount of oxidant issuing from the lance corresponds with the stoichiometric amount for a fuel supplied to the burner. At least 50% of the supplied oxygen for combustion is supplied through the lancing of oxidant, and the oxidant is flowed into the furnace through the lance at a velocity of at least 200 m/s.