Causes and solutions for the inclination of the breast wall of the glass melting furnace

After the rapid expansion of my country's flat glass industry in the past few years, the supply of glass in the glass market is clearly far greater than demand. For this reason, some companies have adopted various measures to reduce costs in order to survive, even without considering the rationality of the plan, resulting in a decline in glass quality. , Shorten the life of the furnace and other issues. This article makes a specific analysis on the inclination of the parapet in the glass melting furnace.
Theories about glass melting
1.1 Fuel combustion mechanism of glass melting furnace
 
The combustion of the fuel in the glass melting furnace is carried out in a small furnace. After the fuel and combustion air enter the furnace, they are burned to form a flame. The batch materials are heated to melt into glass liquid. Finally, the flue gas enters the opposite small furnace and exits the furnace. During the whole combustion process, the flame temperature is high in the middle and low at the two ends, that is, the temperature of entering and exiting the kiln is lower than the temperature in the middle.
1.2 Furnace pressure
The pressure of the float glass furnace is based on the liquid surface pressure of the glass, and the pressure at the pressure point on the breast wall of the clarification part is controlled (automatically by computer) as the standard of the entire furnace. In addition, there are also Manually control the kiln pressure in the flame zone to ensure that the kiln pressure in the flame zone is slightly greater than 1 atmosphere to prevent the (natural) cold air outside the kiln from entering the kiln, reduce the temperature in the kiln, increase energy consumption, and prevent the kiln from overpressure When it is large, the hot air in the kiln rushes out of the kiln, which intensifies the erosion of the furnace.
1.3 Glass melting furnace breast wall structure
The breast wall of the glass melting furnace is composed of breast wall bricks, hook bricks and breast wall supporting irons. The weight of the entire breast wall is carried by the supporting irons. Outside the wall of the melting furnace, a pool wall cooling air is installed to cool it down, and the blowing angle of the cooling air is diagonally upward. Therefore, while cooling the pool wall, it also cools the breast wall support iron.
 
The overall support of the bracing wall of the melting furnace is the bracing iron of the bracing wall, so the reason for the inclination of the bracing wall is the softening and deformation of the bracing iron of the bracing wall. The bricks also slide inward with the forward inclination. The reasons for the high temperature deformation of the parapet support iron are:
 
(1) The cooling air volume of the pool wall is too small
It can be seen from Figure 1 that after the pool wall cooling wind blows through the pool wall, it continues to move upward, hitting the surface of the breast wall support iron, lowering the temperature of the support iron, and protecting the support iron from high temperature deformation. However, when the cooling air volume of the pool wall is small, the cooling effect of the cooling air on the support iron is reduced, and the temperature of the support iron rises. In severe cases, the support iron will be deformed at high temperature and the breast wall bricks will tilt inward.
 
Because the pressure of the pool wall cooling wind of the production line (2) is too small, in addition to the low cooling strength of the pool wall, the wind has no cooling protection effect on the parapet support iron. The temperature of the support iron is too high and deformed. In actual production, the line There was an inward inclination of the pool wall.
(2) The effect of the sealing of the gap between the breast wall and the pool wall on the inward inclination of the breast wall brick
The gap between the breast wall and the pool wall of the melting furnace is usually sealed with polycrystalline mullite fiber felt. During the production process, if the pile of materials severely scratches the pool wall and the polycrystalline mullite fiber, the polycrystalline mullite fiber will be quickly sealed. It will be eroded away, causing the gap to penetrate the fire, and the escaping flame will directly barbecue the bracing iron, which intensifies the deformation of the brace and aggravates the probability of inverting the breast wall bricks.
(3) The influence of flames on the inward inclination of parapet tiles
The combustion of the fuel in the glass melting furnace is carried out in small furnaces. When the ratio of wind and fire in the small furnace is unreasonable, especially when the air volume is small, the burning flame will appear muddy and long, and the fire will pass through the nozzle bricks and the breast wall. The gap between the pool walls rushed out of the kiln and directly grilled the breast wall support iron, which aggravated the deformation of the support iron, and in severe cases caused the inward inclination of the breast wall bricks.
(4) The influence of kiln pressure on the inclination of breast wall tiles
The kiln pressure of the melting furnace is controlled by the pressure of the breast wall of the clarification department as the standard, and the kiln pressure in the flame zone can only be adjusted manually by adjusting the opening of each small furnace gate, and whether it is reasonable is usually manually observed with the naked eye. The length and rigidity of the flame in the observation hole on the back wall of the regenerator can be judged. In the initial stage of production, in order to save energy, sometimes the kiln pressure in the flame zone is set higher than normal. The kiln pressure is high, and the burning loss of the kiln will not appear immediately in the short term. However, in the long run, a large amount of high temperature exhaust gas will be sprayed from the fire hole between the breast wall and the pool wall and the nozzle brick, which increases the temperature of the breast wall support iron. Intensified the deformation of the supporting iron, and finally caused the breast wall bricks to tilt inward.
(5) The influence of plant skylights on parapet support iron and parapet bricks
There are adjustable skylights in the middle of the roof of the melting furnace, and its function is to discharge all kinds of smoke, dust and waste gas in the workshop. In addition, there is another function, which is to generate air flow from the bottom of the kiln to the skylight through exhaust gas, extract the hot air flow in the gap of the small furnace, reduce the temperature of the space in the gap of the small furnace, and then achieve the reduction of the breast wall support iron. The temperature protects the support iron.
In order to save energy and increase the temperature of the space around the furnace, some companies close the skylights of the workshop a lot, the air in the workshop does not flow, the high-temperature hot air in the gap of the small furnace cannot be discharged in time, and the temperature of the breast wall support iron rises, which causes the support iron to be deformed at high temperature. Hidden dangers are buried.
(6) The influence of the design of the gap between the parapet wall and the pool wall on the parapet wall tiles
There are two options in the design of the gap between the breast wall and the pool wall, one is the gap distance is 30mm, and the other is the gap distance is 100mm. These two design options have their own advantages and disadvantages, but in the later stage of the furnace, especially the thickness of the pool wall tiles When the erosion is less than 50mm, the kiln with a gap distance of 100mm has obvious advantages. The reason is that when the gap between the breast wall and the pool wall is large, when the thickness of the pool wall brick is about 50mm, a knife can be placed above the pool wall to protect the pool wall to reduce the erosion of the pool wall. At the same time, the knife brick can be changed. Seal the gap between the pool wall and the parapet wall, reduce the heat dissipation of the gap, reduce the space temperature of the small furnace, reduce the use environment temperature of the parapet wall, and extend the service life of the parapet.
Daily inspection and maintenance
(1) Daily inspection of whether the breast wall tiles are inverted. The phenomenon of breast wall tiles inverted does not happen within a day or two. Therefore, daily tracking and inspection of the changes of the breast wall tiles should be carried out.
 
The inspection method is: regularly measure the distance between the breast wall bricks at different positions and the column of the melting furnace, make a record, and make a comparison work, and check the changes in the distance between the lower and middle two points of each breast wall brick.
(2) The maintenance method of the breast wall tiles after the inward tilting. When the breast wall tiles are found to be tilted inward, measures should be taken in time. On the one hand, check the cause of the occurrence and correct it in time. On the other hand, a water bar is inserted into the chest wall of the furnace on the top of the dome , To block the breast wall tiles with water bars to prevent further deformation and displacement,
Installation method: Open a hole in the top of the furnace section, insert a water bar, adjust the distance between the water bar and the column through the top wire fixed on the column of the furnace, use the principle of leverage, use the dome top as the fulcrum, let the water bar and the breast wall The brick clings to it to block the breast wall brick from moving forward.
Note: During use, observe the water temperature changes of the water bar every shift, and replace the water bar in time if it is found to be leaking.
Conclusion
The inward inclination of parapet bricks is a comprehensive process management problem. For kilns with inward inclination of parapet bricks, almost all the reasons listed above exist, but the main reason is that the air volume on the pool wall is too small. Other reasons are auxiliary. Therefore, always pay attention to the size of the pool wall air volume during the production process.