Diluted Combustion Inlet Configuration for NOx Reduction
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Solution Overview
Problem
Glass furnaces face challenges in reducing nitrogen oxide (NOx) emissions, particularly due to the large diameter of oxidizer inlets, which makes it difficult to separate fuel and oxidizer inlets effectively, leading to high NOx formation and corrosion issues, and existing methods struggle to achieve significant reductions while maintaining thermal energy transmission.
Innovation Solution
A combustion process with an oxidizer inlet containing 10-30% oxygen and a fuel inlet positioned outside the oxidizer inlet, separated by a distance of 0.3 to 4 times the equivalent diameter, with oxidizer emerging at speeds between 10-60 m/s, achieving significant NOx reductions exceeding 45% without compromising thermal energy transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the oxidizer inlet diameter is increased to maintain low gas velocities and prevent material flight, then the separation distance between fuel and oxidizer inlets becomes insufficient, leading to high NOx formation
Solution Approach 1:
The patent positions fuel injectors at the periphery of the oxidizer inlet rather than directly inside it, utilizing the radial dimension. The fuel injectors are arranged in a circle at a distance of 0.6 to 1.5 times the oxidizer inlet radius from the center, creating spatial separation in a different dimensional arrangement that maintains both low gas velocities and sufficient separation distance for NOx reduction
Solution Approach 2:
The fuel injection system is divided into multiple peripheral injectors rather than a single central injector. This segmentation allows fuel to be introduced at multiple points around the oxidizer inlet perimeter, creating distributed combustion zones that reduce peak temperatures and NOx formation while maintaining the required separation from the oxidizer inlet
2Reliability
If the oxidizer inlet diameter is increased to prevent powder take-off and corrosion, then the separation between fuel and oxidizer inlets is reduced, compromising NOx reduction efficiency
Solution Approach 1:
The patent utilizes the radial dimension by positioning fuel injectors at the periphery of the oxidizer inlet at a distance of 0.6 to 1.5 times the oxidizer inlet radius from the center. This dimensional arrangement allows large oxidizer inlet diameters to be used for preventing powder take-off and corrosion while maintaining sufficient separation distance for NOx reduction through peripheral fuel injection
3Object-affected harmful factors
If secondary reduction methods using reducing agents are employed, then NOx emissions are reduced, but storage and handling difficulties and refractory corrosion occur
Solution Approach 1:
The patent converts the harmful effect of high-temperature combustion into a benefit by using the combustion process itself to reduce NOx. Through peripheral fuel injection and distributed combustion zones, the system creates lower peak temperatures that inherently reduce NOx formation, eliminating the need for separate reducing agents and their associated storage and handling problems
Solution Approach 2:
The combustion system performs its own NOx reduction function through the specific arrangement of peripheral fuel injectors and oxidizer inlet configuration. The system self-regulates temperature distribution and combustion zones to minimize NOx formation without requiring external reducing agents, achieving both NOx reduction and operational simplicity
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 results in dramatic NOx reductions, maintaining effective thermal energy transfer and avoiding corrosion, with NOx emissions below 400 mg/Nm³ in glass furnaces, particularly in loop furnaces with regenerators.
Implementation Method 1
a combustion process with an oxidizer inlet containing 10-30% oxygen and a fuel inlet positioned outside the oxidizer inlet
Implementation Method 2
said oxidant emerging into the furnace at a speed of between 10 and 60 m/s
Data Source
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Figure 5~6
AI summary
The invention relates to a combustion method in a furnace provided with a burner including an inlet for an oxidizer containing from 10% to 30% of oxygen, and a fuel inlet giving into the furnace outside of the oxidizer inlet and at a distance therefrom of between 0.3 and 4 times the equivalent diameter of the oxidizer inlet, said oxidizer being fed into the furnace at a speed of between 10 and 60 m/sec. The method can be used for substantially reducing the nitrogen oxide emissions and is particularly useful for glass furnaces.