Moveable Air Flow Diverter Burner for Low-NOx Combustion
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Solution Overview
Problem
Existing burners face challenges in controlling NOx emissions across a range of air-oxygen mixtures, particularly when transitioning between air-fuel and oxy-fuel combustion, and require flexibility in flame mode to manage temperature and production rates efficiently.
Innovation Solution
A burner design featuring an oxidant feed passage, a fuel feed passage surrounded by an air feed, and a movable air flow diverter, which allows for adjustable air proportioning and gas recirculation to stabilize combustion, enabling operation from pure air to pure oxygen with stable and flameless modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If oxygen concentration is increased to enhance flame temperature and production rates, then productivity increases, but NOx emissions increase due to enhanced thermal NOx formation
Solution Approach 1:
The combustion process is divided into multiple stages with separate oxidant injection points. Primary combustion occurs with initial oxidant, followed by secondary oxidant injection further downstream, allowing the flame to elongate and cool before final oxidation completes, reducing peak temperatures and thermal NOx formation while maintaining high overall combustion efficiency
Solution Approach 2:
The burner incorporates movable air flow diverters and adjustable oxidant injection rates that can be dynamically controlled during operation. This allows real-time adjustment of air-oxygen mixture proportions and flow distribution to optimize the balance between productivity and NOx emissions based on varying process conditions
2Loss of energy
If air is replaced with pure oxygen to reduce combustion product volume and improve thermal efficiency, then thermal efficiency improves, but flame stability deteriorates in cold conditions and at low temperatures
Solution Approach 1:
The burner is designed to universally handle multiple oxidant types and proportions, including pure air, air-oxygen mixtures, and pure oxygen. The system incorporates both flame mode capability (for cold conditions and startup) and flameless combustion mode capability (for high-temperature efficient operation), allowing seamless transition between modes based on process requirements
Solution Approach 2:
During startup and cold conditions, the system preliminarily establishes a stable flame using appropriate air-oxygen mixing ratios before transitioning to flameless combustion mode. This preliminary flame establishment ensures reliable ignition and initial heating, after which the system can operate in the more efficient flameless mode at higher temperatures
3Object-generated harmful factors
If flameless combustion is used to reduce NOx and improve temperature uniformity, then NOx emissions decrease and temperature distribution improves, but the minimum temperature requirement of 1400°F cannot be met during heatup and holding periods
Solution Approach 1:
The burner system employs periodic mode switching between flame mode and flameless combustion mode based on process conditions. During heatup periods and holding periods when temperatures are below 1400°F, the system operates in flame mode to generate sufficient heat. Once the temperature threshold is reached, it transitions to flameless combustion mode for NOx reduction and uniform heating, creating a periodic operational pattern that optimizes performance across varying conditions
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 burner effectively controls NOx emissions and maintains uniform heating with high production rates by adjusting air flow and using gas recirculation, suitable for both flame and flameless modes, and operates efficiently with various fuel types.
Implementation Method 1
a movable air flow diverter that is positionable in the air feed around at least a portion of the fuel feed passage and includes a side wall constructed to proportion distribution of the air feed
Implementation Method 2
enabling operation from pure air to pure oxygen with stable and flameless modes
Implementation Method 3
Burner with a moveable air flow diverter... combustion of a fuel... flame by the combustion of a fuel
Implementation Method 4
maintains uniform heating with high production rates
Data Source
AI summary
A burner includes an oxidant feed passage, a fuel feed passage surrounding the oxidant feed passage, an air feed surrounding the fuel feed passage, a movable air flow diverter and, optionally, a flame nozzle. The movable air flow diverter and/or flame nozzle are independently configured to create one or a plurality of gas recirculation regions adjacent the downstream tip of the burner to improve the mixing and reaction of the fuel and oxidant, and overall combustion process efficiency. A related furnace and method for generating a stable flame with the burner are also provided.