End-Fired Loop Furnace for High Alumina Glass Fibers
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Solution Overview
Problem
Conventional glass melting processes, particularly those using transverse burner furnaces, face difficulties in melting glass compositions rich in alumina or zirconia due to their high melting points, and the use of boron oxide as a flux can compromise corrosion and electrical resistance, while loop furnaces are not suitable for producing fiberglass due to parasitic phase formation caused by boron presence.
Innovation Solution
Utilizing a loop furnace with 100% fossil fuel introduced through a loop flame, air or oxygen-enriched air as oxidizers, and regenerators to achieve high combustion efficiencies over 70%, eliminating the need for boron oxide and reducing parasitic phase formation, allowing for the melting of glasses with high Al2O3 and ZrO2 content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If boron oxide is added as a flux to melt high alumina glass compositions, then melting efficiency is improved, but corrosion resistance and electrical resistance deteriorate
Solution Approach 1:
The invention extracts boron oxide from the glass composition entirely, replacing it with alternative fluxes (sodium oxide, potassium oxide, calcium oxide, magnesium oxide) that do not compromise corrosion or electrical resistance. This extraction eliminates the harmful effect while maintaining melting efficiency through optimized furnace design and alternative chemical composition.
2Productivity
If oxygen is used as an oxidizer to achieve high combustion efficiency and melting temperature, then melting performance is improved, but production cost increases
Solution Approach 1:
The invention changes the oxidizer parameter from pure oxygen to air (or air with limited oxygen enrichment), significantly reducing material cost. Compensation for the lower oxygen concentration is achieved through optimized burner design, increased combustion efficiency, and extended residence time in the melting zone, maintaining adequate melting temperature without expensive oxidizer.
3Productivity
If a loop furnace is used to melt glass, then combustion efficiency is improved and cost is reduced, but parasitic phase formation occurs making the glass unsuitable for fiberizing
Solution Approach 1:
The invention applies local quality by creating distinct thermal zones within the loop furnace: a high-temperature zone for complete melting and a controlled cooling zone that prevents parasitic phase formation. The flame configuration and batch placement are optimized locally to ensure uniform heating and prevent localized compositional variations that would cause unwanted phases.
Solution Approach 2:
The invention performs preliminary homogenization of the glass batch before complete melting, ensuring uniform distribution of all components including alumina and zirconia. This preliminary action prevents localized compositional variations that would lead to parasitic phase formation during subsequent melting and cooling processes.
4Ease of manufacture
If transverse burner furnaces are used to melt conventional glass compositions, then melting is achieved, but high alumina and zirconia compositions cannot be melted effectively
Solution Approach 1:
The invention introduces dynamic control of the burning process through adjustable burners that can modify flame intensity, direction, and distribution. This dynamic capability allows the furnace to adapt to different glass compositions, particularly high alumina and zirconia materials requiring higher and more uniformly distributed temperatures, while maintaining ease of operation through controlled adjustment mechanisms.
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
Achieves high combustion efficiencies and produces glass fibers with minimal defects, free from boron-related issues, enabling the production of high-quality glass fibers with improved mechanical strength and corrosion resistance without the expense of pure oxygen.
Implementation Method 1
100% of the fossil fuel being introduced by the loop flame
Implementation Method 2
regenerators to achieve high combustion efficiencies over 70%
Implementation Method 3
melting of glasses with high Al2O3 and ZrO2 content
Data Source
Figure 1~4
Figure 5~6
AI summary
The invention relates to a method and a device for preparing a glass having a low boron content and loaded with alumina or zirconia, the melting of the vitrification materials being carried out in an end-fired furnace provided with regenerators (4, 4i), the main portion of the fossil energy being introduced by the loop flame in which the oxidant and the fuel are introduced in the upstream side (1) of said furnace, the oxidant consisting of air or oxygen-enriched air. The melting compartment can be followed by a glass fibering unit. The invention can be used in the production of fibres having combustion yield and a high productivity.