Solid Fuel Burner Nozzle Design for Stable Combustion
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Solution Overview
Problem
Existing solid fuel burners face issues with fuel particles colliding with the inner wall of the nozzle, leading to abrasion and re-scattering, which disrupts the flow and results in non-uniform oxygen concentration distribution, affecting combustion stability, especially when handling fuels with high volatile matter like wood, peat, and coal.
Innovation Solution
The design incorporates an oxygen-containing gas addition nozzle with a right-angle orientation between the side plate and the fuel nozzle inner wall to minimize radial velocity components, reducing collisions and re-scattering, while increasing oxygen and fuel concentration in the outer circumferential portion, ensuring stable combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the oxygen-containing gas addition nozzle is designed with an acute angle between the side plate and fuel nozzle inner wall to facilitate gas flow, then the gas flow path is smooth, but fuel particles collide with the inner wall causing abrasion and re-scattering
Solution Approach 1:
The patent inverts the conventional acute angle design by using a right angle (90 degrees) between the side plate and fuel nozzle inner wall. This inversion prevents fuel particles from colliding with the inner wall while still maintaining smooth gas flow through the nozzle structure.
Solution Approach 2:
The patent changes the critical geometric parameter of the nozzle angle from an acute angle to a right angle (90 degrees). This parameter change fundamentally alters the flow dynamics, eliminating radial velocity components that cause fuel particle collision while preserving axial flow smoothness.
2Reliability
If mixed gas of combustion exhaust gas and oxygen-containing gas is used as carrier gas to prevent spontaneous combustion, then oxygen concentration is reduced suppressing combustion, but the burning rate becomes low and flame stability is deficient
Solution Approach 1:
The patent applies local quality by injecting oxygen-containing gas at specific locations within the fuel nozzle using addition nozzles. This creates localized high-oxygen zones at the fuel injection point while maintaining low oxygen concentration in the bulk carrier gas, thus preventing spontaneous combustion overall but ensuring adequate oxygen for stable burning at the combustion zone.
Solution Approach 2:
The patent performs preliminary action by pre-mixing oxygen-containing gas with the carrier gas before the fuel reaches the combustion zone. This preliminary oxygen supplementation ensures that when fuel particles are ejected, they have access to adequate oxygen for immediate combustion, preventing flame instability without requiring high overall oxygen concentration that would cause spontaneous combustion.
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 suppresses fuel particle collisions with the nozzle wall, reduces abrasion, and enhances oxygen and fuel concentration, leading to stable and efficient combustion with improved flame stability and reduced load requirements.
Implementation Method 1
oxygen-containing gas addition nozzle projected and installed inside the fuel nozzle for ejecting oxygen-containing gas having a velocity component in a circumferential direction of the fuel nozzle
Implementation Method 2
the angle formed by the side plate of the oxygen-containing gas addition nozzle and the inner wall of the fuel nozzle is a right angle, so that a velocity component of the fuel particles in a radial direction is minimized
Implementation Method 3
The combustion exhaust gas reduces the oxygen concentration in the fuel circumference, suppresses the oxidation reaction (combustion) of the fuel, and prevents spontaneous combustion
Implementation Method 4
the combustion exhaust gas has a function of drying the moisture in the fuel by its potential heat
Data Source
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AI summary
The present invention is to provide a solid fuel burner for suppressing collision of fuel particles to an inner wall of a fuel nozzle, increasing fuel concentration and oxygen concentration in an outer circumferential portion in the fuel nozzle while reducing abrasion of the fuel nozzle, thereby enabling stable combustion. A solid fuel burner 42 of the present invention comprising a fuel nozzle 11 for ejecting a mixed fluid of solid fuel and carrier gas therefor, an oxygen-containing gas nozzle 13, 14 arranged outside the fuel nozzle for ejecting oxygen-containing gas, and at least one oxygen-containing gas addition nozzle 12 projected and installed in the fuel nozzle for ejecting oxygen-containing gas having a velocity component in a circumferential direction of the fuel nozzle, wherein the oxygen-containing gas addition nozzle 12 has a nozzle outlet 12A, 12B, 12C in the circumferential direction of the fuel nozzle, characterized in that: the oxygen-containing gas addition nozzle 12 is shaped so as to contract a projected section thereof in an axial direction of the burner toward a central axis of the burner.