What are the causes of sidewall erosion in glass furnace?
As the core device of glass production, how to extend the life of glass melting furnace has always been a concern of glass producers. The sidewall?of glass melting furnace is the most critical part of glass melting furnace. Its erosion degree directly affects the service life of glass melting furnace. To protect the sidewall?of glass melting furnace, we first need to understand why the sidewall?is eroded.
1. Reasons for erosion of glass melting furnace sidewall
(1) The batch materials of glass production are heated by high-temperature radiation of solid flame along the longitudinal direction of the furnace. The first stage is the silicate reaction between various components in the raw materials, the second stage is the unreacted foamy silicate slag, and the third stage is gradually melted into glass liquid. Sodium oxide penetrates into the interior from the glass phase and pores of the sidewall?bricks by penetration, diffusion and replacement. The protective layer is lost under the erosion of glass liquid temperature and the scouring of glass liquid flow. This is the main factor of sidewall?erosion.
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(2) Due to the horizontal and vertical temperature differences in the melting furnace, there are actually various complex horizontal and vertical glass liquid convections under the seemingly calm glass liquid surface in the melting furnace. In the material-making area, foam area, and transparent glass liquid area, they are heated not only by the flame, but also by the molten circulating glass liquid flow. It is these diverse convections that promote the melting, clarification and homogenization of glass, and also cause the erosion of the sidewall.
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(3) From the practical experience of glass melting furnace production, the area from the glass liquid surface line to 300 mm below is the most serious part of the sidewall?erosion due to the low viscosity and fast flow rate of the glass liquid. The most serious part of the sidewall?erosion is the sidewall?of the material-making area small furnace at the junction of the gas, liquid and solid phases, rather than the sidewall?of the small furnace at the junction of the gas and liquid phases with the highest temperature. Therefore, the material pile close to the sidewall?is most likely to cause erosion of the sidewall.
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(4) Generally, glass melting furnaces use air cooling measures to protect the sidewall. By blowing air to the outside of the sidewall?about 100 mm below the liquid surface, the local temperature inside the sidewall?bricks is reduced, delaying the erosion of the sidewall?bricks by the material pile and glass liquid. sidewall?cooling air plays a very important role in extending the life of the sidewall. If the blowing position is unreasonable, or the blowing volume is too small or the blowing intensity is weak, the cooling wind of the sidewall?cannot be fully utilized, resulting in accelerated erosion of the sidewall?bricks. If the sidewall?wind control is unstable, it is easy to cause the sidewall?bricks to burst due to rapid heating and cooling.
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(5) At present, most float glass manufacturers adopt the "double high heat load" melting operation system, increase the temperature of the 1#~2# small furnace, and correspondingly increase the temperature of the feeding pool, resulting in more active roots of the pile. Due to the melting operation, the temperature of the sidewalls on both sides is lower than the temperature in the middle of the melting furnace, and the lateral convection of the glass liquid will lead the pile of materials in the process of moving forward to the sidewall. In addition, due to the fact that large float glass melting furnaces mostly use two inclined blanket feeders, each material strand cannot adjust the direction of the material strand separately, etc., the longer the time, the easier it is to form an "inverted eight-shaped" pile of materials that is inclined to the sidewalls on both sides. The skewed material pile directly adheres to the small furnace sidewall?bricks in the material-making area and gradually melts, which has a greater scouring effect on the sidewall?and accelerates the scouring and erosion speed of the sidewall?bricks in the small furnace in the material-making area.
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The above is a brief analysis of the reasons for the erosion of the glass melting furnace sidewall. In the next article, I will talk about the maintenance methods of the glass melting furnace sidewall?to extend the life of the glass furnace. Please continue to pay attention, thank you!
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