Premixed Burner Tip Plate Cooling for Low NOx Emissions
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Solution Overview
Problem
Existing premix burners fail to achieve low NOx emissions below 9 ppm with residual oxygen levels above 3%, and they are not compatible with commercially available boilers, leading to inefficient operation and higher emissions.
Innovation Solution
A burner design with a combustion head featuring a tip plate and two concentric tubes, where the inner tube supplies cooling air through the tip plate and the outer tube delivers a premixed air-fuel mixture at an angle, creating a conical flame with a lower temperature and enhanced return flows to reduce NOx emissions, and mechanical adjustment elements allow for optimization with various boiler configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a long combustion head is used to achieve low NOx emissions, then NOx emissions are reduced, but residual oxygen increases and compatibility with commercial boilers decreases
Solution Approach 1:
The combustion head is divided into multiple sections with different functions: a first section for stable flame establishment and a second section for low-NOx combustion. This segmentation allows each section to be optimized for its specific purpose, achieving low NOx emissions without excessive residual oxygen
Solution Approach 2:
Different regions of the combustion head have different structural characteristics. The first section has a larger diameter for stable flame establishment, while the second section has a smaller diameter for low-NOx combustion. This local differentiation optimizes combustion in each region
2Object-generated harmful factors
If a long combustion head is used to achieve low NOx emissions, then NOx emissions are reduced, but compatibility with commercial boilers decreases
Solution Approach 1:
The combustion head is divided into a first section and a second section, allowing the burner to be adapted to different boiler types. The first section can be configured for various boiler configurations while the second section maintains low-NOx combustion characteristics
Solution Approach 2:
The burner includes adjustable components that allow optimization for different boiler configurations. This dynamic adjustability enables compatibility with commercial boilers while maintaining low NOx emissions
3Productivity
If the tip plate width is reduced to improve combustion efficiency, then combustion efficiency improves, but flame stability decreases
Solution Approach 1:
The tip plate has different width characteristics at different locations. The optimized width distribution maintains flame stability while improving combustion efficiency by controlling the flame shape and combustion zone
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 achieves NOx emissions below 15 ppm with less than 3% residual oxygen and below 5 ppm with less than 6% residual oxygen, while being compatible with commercially available boilers, significantly reducing NOx emissions and carbon monoxide burning efficiency.
Implementation Method 1
it is for cooling the tip plate that the inner tube is additionally provided with a supply of combustion air for conveying the combustion air through the tip plate's air openings
Implementation Method 2
between a side edge of the tip plate and the plane of the tip plate is an oblique angle of incidence for directing a gas delivered forward of the tip plate away from the longitudinal center axis of the combustion head
Implementation Method 3
The outer tube is provided with a supply of premixed air-fuel mixture from the burner's frame member for conveying the premixed air-fuel mixture outward of the combustion head by way of the apertures included in the body of the outer tube
Implementation Method 4
a boiler-burner assembly for burning a premixed air-fuel mixture with a flame generated inside a boiler
Data Source
AI summary
The invention relates to a burner installable to a boiler for burning a premixed air-fuel mixture, said burner comprising a frame member provided with an elongated combustion head protruding from the frame member and having what in a view from the frame member is its distal end provided with a tip plate. In said burnerbetween a side edge of the tip plate and the plane of the tip plate is an oblique angle of incidence for directing a gas delivered forward of the tip plate away from the longitudinal center axis of the combustion head,the combustion head has its tip plate provided with a plurality of air openings extending through the tip plate and it is for cooling the tip plate that the inner tube is additionally provided with a supply of combustion air for conveying the combustion air through the tip plate's air openings.