Adjustable Burner Air Supply for Lean Fuel Combustion
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Solution Overview
Problem
Existing burners in industrial furnaces, such as rotary kilns, lack ease of adjustment and efficiency in operating with lean fuels, limiting their ability to effectively utilize secondary air from the furnace hearth.
Innovation Solution
A burner design featuring coaxial pipes with adjustable external air supply pipes and a flame stabilizer, allowing for axial and tangential air flow control, enabling high lean fuel operation and efficient secondary air suction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If existing burner configurations are used, then structural simplicity is maintained, but ease of adjustment and efficiency with lean fuels deteriorates
Solution Approach 1:
The patent implements adjustable air supply pipes that can move axially relative to each other, transforming a static burner configuration into a dynamic one. The second external air supply pipe comprises two tubes that can displace axially to modify the overall air flow, enabling easy adjustment of combustion parameters without complex mechanical systems.
Solution Approach 2:
The burner is divided into multiple functional segments including central air supply pipe, peripheral fuel supply pipes, and two separate external air supply pipes. This segmentation allows independent adjustment of each component, particularly the external air supply pipes that can be modified by simple relative axial displacement to control air flow characteristics.
2Productivity
If existing burners are used, then basic combustion function is provided, but efficiency with lean fuels and secondary air suction deteriorates
Solution Approach 1:
The adjustable configuration of external air supply pipes enables dynamic optimization of air-fuel ratio for lean fuel operation. By varying the relative axial position of the two tubes in the second external air supply pipe, the overall air flow can be precisely controlled to achieve high proportions of lean fuels while maintaining stable combustion.
Solution Approach 2:
The patent creates different flow characteristics in different regions of the burner. The channels in the first external air supply pipe impart zero tangential component (axial flow), while the second external air supply pipe can be adjusted to create variable tangential components, optimizing local flow patterns for efficient secondary air suction and lean fuel combustion.
3Productivity
If air flow is increased for lean fuel operation, then combustion efficiency improves, but dust deposition risk increases
Solution Approach 1:
The patent optimizes local flow characteristics by directing axial unit flows from the first external air supply pipe in a manner that prevents dust deposition. The channels are arranged and shaped to create specific flow patterns that maintain high combustion efficiency while minimizing conditions that lead to dust accumulation on burner surfaces.
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 a simple and adjustable configuration, enhancing air flow management and allowing for a higher proportion of lean fuel operation, thereby improving combustion efficiency and reducing dust deposition risks.
Implementation Method 1
These channels are adapted to impart a zero tangential component to the air moving therein. Therefore, the air coming from this first conduit (6) has an axial flow which is formed by the series of axial unit flows.
Implementation Method 2
The outlet orifices (11) are shaped so that the speed of the air leaving it is between 150 and 350 m/s, and preferably between 180 and 250 m/s (or even between 200 and 250 m/s), in operation.
Implementation Method 3
each channel (10) of the first series comprises, between its outlet orifice (11) and the reduction portion (12), a conical acceleration portion (13) which makes it possible to have unitary axial air flows resulting in less air return close to the front of the burner (1) and to avoid any separation of air from the circular perimeter of the orifice output (11)
Implementation Method 4
The outlet orifices (11) are separated from the two orifices (11) which are adjacent to it by an angular gap whose value is between two (or even three) and ten times the angular extent of the orifice (11). This separation makes it possible to have axial unit flows sufficiently spaced from each other to allow good suction of the secondary air present in the hearth around the tube (8)
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a burner (1) comprising a first external air supply pipe (6) situated on the outside of any other pipe (2, 4, 5, 7), and a second external air supply pipe (7) surrounding a peripheral fuel supply pipe (5) which surrounds a central air supply pipe (2). According to the invention, the first external pipe (6) is delimited by two immovable tubes (8, 9) carrying axial first ducts (10); the second external pipe (7) is delimited by an internal tube (14) carrying open second ducts (15) exhibiting tangential divergence that decreases in the upstream to downstream direction, and by an external tube (9) able to move with respect to the internal tube (14) covering the second ducts (15) and comprising a portion (18) that diverges in the upstream to downstream direction; the entirety of the air flowing through the external pipes (6, 7) emerging via the first and second ducts (10, 15).