Furnace Intense Heating Means for Batch Emissivity
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Solution Overview
Problem
Glass furnaces with low cullet content, such as those using sand, exhibit low thermal efficiency due to the low spectral emissivity of unmelted batch materials, leading to significant reflection of thermal radiation and inefficient heat transfer, particularly in the initial unmelted blanket surface.
Innovation Solution
Implementing an intense heating means, such as a curtain of downwardly directed flames or an electromagnetic radiation emitter, near the point of entry of the batch materials to rapidly melt a surface layer and increase the emissivity of the batch blanket, thereby enhancing radiative heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If batch materials with low cullet content (e.g., sand) are used, then the furnace can process raw materials effectively, but the spectral emissivity of the unmelted batch materials is low, causing significant reflection of thermal radiation and low thermal efficiency
Solution Approach 1:
The patent applies preliminary action by introducing an intense heating means at the entrance of the furnace to pre-melt the surface of the batch blanket before it enters the main combustion zone. This preliminary melting increases the emissivity of the batch materials from approximately 0.2 to beyond 0.6, thereby reducing thermal radiation reflection and improving overall thermal efficiency. The intense heating means acts in advance to prepare the batch materials for more efficient heat absorption in the main furnace zone.
2Loss of energy
If the length of the unmelted batch blanket surface is reduced, then thermal efficiency improves, but the furnace design becomes more complex
Solution Approach 1:
The patent introduces an intermediary element - the intense heating means - positioned at the furnace entrance to bridge the gap between the cold batch materials and the main combustion zone. This intermediary heating device rapidly melts the batch surface, increasing emissivity and reducing the length of the unmelted blanket surface. The intermediary heating means acts as a mediator that prepares the batch materials for efficient heat transfer in the main furnace, thereby improving thermal efficiency without fundamentally redesigning the entire furnace system.
3Loss of energy
If intense heating is applied over a longer length, then more batch materials are melted and emissivity increases, but the heat flux density decreases and thermal efficiency is reduced
Solution Approach 1:
The patent applies local quality by concentrating intense heating in a localized zone at the furnace entrance rather than distributing heating uniformly along the entire furnace length. The intense heating means is positioned to act specifically on the batch blanket surface at the point of entry, creating a localized melted layer with high emissivity. This localized approach maintains high heat flux density (greater than 200 kW/m²) in the critical zone where it is most needed, while avoiding the dilution of heat flux that would occur with extended heating zones.
4Loss of energy
If the heat flux density is increased to melt the batch surface rapidly, then emissivity increases and thermal efficiency improves, but the energy consumption increases
Solution Approach 1:
The patent applies partial action by using intense heating means that provides excessive heat flux density (greater than 200 kW/m², advantageously greater than 300 kW/m²) over a limited zone at the furnace entrance. This excessive local heating rapidly melts the batch surface to achieve high emissivity, but only in the critical zone where it is most needed. The partial application of intense heating - rather than uniform heating throughout the furnace - reduces overall energy consumption while achieving the desired thermal efficiency improvement.
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 approach significantly improves thermal efficiency by increasing the heat flux at the batch blanket surface, reduces the length of the unmelted surface, and can increase the output of existing furnaces by enhancing radiative heat transfer and reducing material fly-off and fouling.
Implementation Method 1
the spectral emissivity of the batch materials containing little cullet, especially sand, in the unmelted state is low, around 0.2 in the 0.5 to 3.0 μm wavelength range. As a result, the energy arriving by thermal radiation on the surface of the blanket is largely reflected.
Implementation Method 2
at least one intense heating means predominantly covering the width of the blanket in order to melt a surface layer of the batch materials introduced and to increase the emissivity of the batch blanket
Implementation Method 3
The intense heating means may be formed by a curtain of flames that are downwardly directed from a line of burners extending above the batch blanket, in the direction perpendicular to the direction of flow of the batch materials.
Implementation Method 4
The intense heating means may be formed by a curtain of flames that are downwardly directed from a line of burners
Data Source
AI summary
Furnace for melting batch materials comprising: a tank (3) covered by a crown (4); a combustion zone (5) provided with burners (6); an inlet (8) for charging it with the batch materials; a downstream outlet for the melted materials, the tank containing a melt (7) when the furnace is operating and the batch materials forming a batch blanket (G) that floats on the melt and is progressively melted; the furnace includes, near the charging inlet (8), an intense heating means (B), predominantly covering the width of the batch blanket, for melting a surface layer of the materials introduced and for increasing the emissivity of the batch blanket.