Burner System Staged Fuel and IFGR for NOx Reduction
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Solution Overview
Problem
Current burner designs for industrial heating systems face challenges in reducing NOx emissions, as they often require complex configurations and higher costs to achieve lower combustion temperatures, which are essential for minimizing nitrogen oxide production.
Innovation Solution
The implementation of a burner system that combines staged fuel operation with internal flue gas recirculation (IFGR) using a single ejector ring with a larger tip area and closer ejection ports, allowing for enhanced flue gas mixing and reduced peak flame temperatures, thereby decreasing NOx emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If complex burner configurations are used to reduce combustion temperature, then NOx emissions are reduced, but device complexity and cost increase
Solution Approach 1:
The patent combines staged fuel operation and internal flue gas recirculation (IFGR) into a single integrated burner design. The fuel discharge ring assembly integrates multiple ejection ports for staged fuel delivery while simultaneously incorporating IFGR functionality, merging two separate NOx reduction approaches into one unified structure that reduces complexity compared to implementing them separately
Solution Approach 2:
The burner divides fuel delivery into multiple staged zones using the fuel discharge ring assembly with multiple ejection ports. Fuel is injected in stages at different positions and rates, creating separate combustion zones that prevent excessive peak temperatures. This segmentation of the combustion process enables NOx reduction through controlled staging while maintaining system simplicity
2Object-generated harmful factors
If combustion temperature is reduced to minimize NOx production, then NOx emissions decrease, but combustion efficiency and heat generation may be compromised
Solution Approach 1:
The staged fuel operation implements periodic combustion phases with distinct fuel-rich and fuel-lean zones. The first stage creates a fuel-rich zone that limits peak temperature, followed by a second stage that completes combustion in a controlled manner. This periodic structure ensures complete fuel combustion and maintains heat generation efficiency while keeping peak temperatures below NOx formation thresholds
Solution Approach 2:
The system dynamically adjusts combustion parameters including fuel injection rate, staging ratio, and flue gas recirculation rate to optimize the balance between NOx reduction and combustion efficiency. By changing these parameters adaptively, the burner maintains high combustion efficiency while operating at temperatures that minimize NOx production
3Object-generated harmful factors
If staged fuel operation and IFGR are combined in a single ejector ring, then NOx emissions are reduced at lower cost, but the ejector design complexity increases
Solution Approach 1:
The fuel discharge ring assembly serves multiple functions simultaneously: it acts as the fuel injection system for staged combustion, provides the structure for IFGR mixing, and functions as the primary burner component. This multi-functionality consolidates what would otherwise require separate components, simplifying manufacturing while achieving both staged fuel operation and IFGR for NOx reduction
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 approach effectively reduces NOx emissions at lower costs and increased efficiency, providing improved flame stability and turndown ratios while maintaining high performance.
Implementation Method 1
Designs using Internal Flue Gas Recirculation (IFGR) wherein some of the burner fuel passes through and mixes with the inert products of combustion (flue gas) in the combustion system to form a diluted fuel which burns at a lower peak flame temperature
Implementation Method 2
Since the combustion process is a reaction between oxygen and the burner fuel, the objective of delayed combustion is typically to reduce the rate at which the fuel and oxygen mix together and burn
Implementation Method 3
Staged air designs wherein the combustion air is typically separated into two or more flows to create separate zones of lean and rich combustion
Data Source
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AI summary
A burner apparatus for a fired-heater system and a method of burner operation wherein the burner fuel is ejected outside of the burner wall from a surrounding fuel discharge ring, or from a lateral elongate ejection bar in the case of a flat flame burner, to a combustion zone projecting from the forward end of burner wall. The burner apparatus and method reduce NOx production by a combination of enhanced internal flue gas recirculation and staged fuel operation.