As the core equipment in glass production, the fused cast AZS blocks inside glass furnaces play an important role. Fused cast AZS blocks possess excellent properties such as high-temperature resistance, corrosion resistance, and mechanical strength, creating a stable high-temperature environment for glass furnaces and ensuring the smooth progress of glass melting and forming processes. However, even with their outstanding initial performance, the service life of fused cast AZS blocks can be significantly reduced without proper daily maintenance, thereby affecting the operational efficiency and production benefits of the entire glass furnace. In actual production, many small details of seemingly insignificant daily maintenance are the key to extending the service life of fused cast AZS blocks, which is worth our in-depth exploration and strict implementation.
1.Temperature Monitoring and Regulation
The temperature distribution inside a glass furnace is complex and constantly changing, with different parts of the fused cast AZS blocks experiencing varying temperatures. Accurate temperature monitoring is the primary step in understanding the working condition of fused cast AZS blocks. Monitoring equipment such as thermocouple and infrared temperature sensor can be reasonably arranged in the key positions of the furnace, such as melting end, clarifying area and feeding channels, so as to obtain the temperature data of the environment where the fused cast AZS block is located in real time. For example, the sidewall blocks of the melting end, which are in direct contact with high-temperature glass liquid, often experience higher temperatures within the furnace, and temperature fluctuations can significantly affect the block structure. Through multi-point, high-precision temperature monitoring, even minor deviations from the normal temperature range can trigger early warnings, prompting operators to investigate and adjust.
.png)
To ensure that fused cast AZS blocks operate within an appropriate temperature range, effective temperature regulation is essential. On one hand, for fuel-heated furnaces, it is necessary to precisely adjust the fuel supply, air ratio, and burner operation based on temperature monitoring data to ensure stable combustion and uniform heat release, allowing the furnace temperature to rise or fall steadily. For example, an automated combustion control system can adjust the gas valve opening in real-time according to the set temperature curve, avoiding sudden temperature fluctuations caused by unstable fuel supply. On the other hand, for electrically heated furnaces, it is crucial to accurately control parameters such as electrode current and voltage to ensure a stable and efficient conversion of electrical energy into heat. Additionally, attention should be paid to the furnace's insulation condition. Regularly inspect the integrity of the insulation layer and repair or replace damaged insulation materials, such as ceramic fiber wool or lightweight insulating bricks, to prevent excessive heat loss, which would force the fused cast AZS blocks to endure greater thermal stress to maintain furnace temperature, thereby extending their service life.
During the operation of glass furnaces, fused cast AZS blocks face erosion threats from multiple sources. Alkaline oxides in the glass liquid, such as sodium oxide and potassium oxide, react with the main components of fused cast AZS blocks, such as aluminum oxide and silicon dioxide, gradually destroying the brick's crystal structure and making it porous and brittle. Additionally, volatiles generated during the melting of raw materials, incompletely melted particles, and corrosive gases in the furnace atmosphere can adhere to the surface of fused cast AZS blocks, further penetrating and eroding their internal structure. Fused cast AZS blocks subjected to long-term erosion not only experience a significant decline in strength and refractory performance but also lead to reduced furnace sealing, increased heat loss, and compromised glass melting quality and production efficiency. In severe cases, this can even cause furnace safety accidents.
To resist erosion, protective coatings can be applied to the surface of fused cast AZS blocks. For example, high-temperature oxidation- and erosion-resistant coatings containing zirconium or chromium can form a physical and chemical barrier between the fused cast AZS blocks and the erosive medium, effectively blocking the erosion of glass liquid and gases. Regularly repairing and renewing the coatings on the surface of fused cast AZS blocks ensures the continuity of their protective effect. At the same time, regular cleaning of the furnace interior is also a critical measure. During shutdowns for maintenance, the surface of fused cast AZS blocks should be thoroughly cleaned. First, use specialized cleaning tools such as scrapers and steel brushes to remove large glass condensates and nodules, then apply appropriate chemical cleaning agents to remove stubborn stains and erosion products through soaking and rinsing. For hard-to-reach areas, auxiliary equipment such as high-pressure water guns and endoscopes can be used to ensure the surface of the fused cast AZS blocks is as clean as possible, reducing the ongoing impact of erosive factors.
The interior of a glass furnace operates under a certain pressure environment, and abnormal changes in pressure, whether positive or negative, can adversely affect fused cast AZS blocks. When the positive pressure is too high, the glass liquid will produce stronger scouring force on the fused cast AZS block under the action of pressure, and accelerate the wear of the block surface; Excessive negative pressure may lead to the outside cold air being sucked into the furnace, resulting in a sharp drop in local temperature, causing thermal stress in the fused cast AZS block, and then cracks and other damage. By installing pressure sensors in different parts of the furnace, real-time monitoring of the pressure changes in the furnace, the operator can timely grasp the ventilation status of the furnace, gas flow, etc., in order to reasonably adjust the flue ram, fan and other ventilation equipment, maintain the normal and stable pressure environment in the furnace, and ensure the normal use of fused cast AZS blocks.
During the daily operation of glass furnaces, processes such as charging, discharging, and stirring of glass liquid subject fused cast AZS blocks to various mechanical stresses. For example, when charging raw materials into the melting end, if the material falls too quickly or with excessive impact force, it can directly strike the sidewall blocks, causing surface damage. To mitigate the effects of mechanical stress, buffer devices such as rubber linings or chutes can be installed at the charging port to slow down the falling speed and impact force of the materials. During the discharging process, it is essential to ensure a steady flow of glass liquid to avoid sudden changes in flow rate that could exert pulling forces on the fused cast AZS blocks. Additionally, regularly inspect the structural components of the furnace, such as the steel frame and support beams, to ensure their stability and prevent uneven stress on the fused cast AZS blocks due to structural deformation, thereby keeping the stress within a reasonable range and extending their service life.
Regular visual inspections of fused cast AZS blocks in glass furnaces are an essential means of identifying potential issues. Operators need to periodically enter the furnace (during shutdowns and under safe conditions) or use peepholes and endoscopes to conduct a comprehensive and detailed inspection of the surface of fused cast AZS blocks. Particular attention should be paid to the presence of cracks, even fine hairline cracks, as these can expand under the continuous influence of thermal stress, mechanical stress, and erosion, eventually leading to spalling or even breakage of the bricks. Additionally, look for signs of spalling or chipping on the brick surface, as these often indicate significant internal structural damage. Changes in the color of the brick surface should also be noted, as discoloration may suggest chemical reactions or exposure to abnormal high temperatures, requiring further analysis and appropriate measures.
Once the above problems are found in the fused cast AZS blocks, it is important to repair them in time. For smaller cracks, special high-temperature repair agents can be used to fill and repair. These repair agents usually have good high-temperature resistance and cohesiveness, and after applying to the crack, after proper curing treatment, they can fill the crack and enhance the integrity of the brick body. In the operation, it is necessary to strictly follow the instructions for the use of the repair agent, and control the thickness and uniformity of the coating, as well as the temperature and time of curing. For the parts with peeling and falling blocks, the damaged area should first be cleaned up, the loose fragments and impurities should be removed, and then the refractory material with similar performance to the original fused cast AZS block should be repaired. The original shape and structure of the brick can be restored by masonry, smearing, and other methods. After repair, it is necessary to ensure that the new and old materials are tightly combined and can jointly withstand various forces in the furnace. Thus prolonging the effective use time of the fused cast AZS block.
In addition to the daily maintenance tasks mentioned above, regular comprehensive performance testing and evaluation of fused cast AZS blocks are essential. The test items include physical performance indicators such as refractoriness, normal temperature and high-temperature strength, thermal expansion coefficient, density, and chemical performance indicators such as resistance to glass liquid erosion and alkali. Using professional testing equipment and methods, such as high-temperature furnaces for refractoriness testing and pressure testing machines for strength evaluation, accurate performance data of the fused cast AZS blocks can be obtained. By comparing these data with the initial performance and industry standards, the extent of performance degradation can be assessed, providing a scientific basis for subsequent maintenance and replacement decisions.
According to the performance test results, if a certain performance index of the fused cast AZS block has been close to or lower than the safe use range, it is necessary to consider taking corresponding measures. For example, if the erosion resistance of the fused cast AZS blocks is significantly reduced, in addition to strengthening protection and cleaning efforts, it may be necessary to plan for the replacement of severely damaged bricks to prevent the failure of individual bricks from affecting the stability of the entire furnace lining. At the same time, through the analysis of multiple test data, it can also summarize the performance of the fused cast AZS block under the specific working conditions of the furnace, further optimize the daily maintenance program, improve the pertinence and effectiveness of the maintenance work, and better extend the service life of the fused cast AZS block.
The daily maintenance work of fused cast AZS blocks in glass furnaces involves many subtleties, from temperature monitoring and control, erosion protection, and cleaning, to pressure and mechanical stress monitoring, appearance inspection and repair, and then to regular performance testing and evaluation, each link is closely linked, which jointly affects the service life of fused cast AZS blocks. Only by paying attention to these small details of daily maintenance and strictly following scientific and reasonable methods and processes can we ensure that the fused cast AZS block plays a stable and reliable role in the glass furnace for a long time, reduce the cost increase and production interruption caused by frequent replacement of the fused cast AZS block, and ensure the efficient operation of the glass furnace. Glass production enterprises need to create greater economic benefits and sustainable development for the good situation. Enterprises should take the daily maintenance of fused cast AZS blocks as an important production management work to catch, and train a professional maintenance team, equipped with advanced maintenance tools and testing equipment, and constantly improve the quality and level of maintenance work so that the use of fused cast AZS blocks in the glass furnace can be extended to the maximum.
Henan SNR Refractory Co., Ltd（SNR） produces a variety of high-quality fused cast AZS blocks.If you have any needs, please contact me.
