The pool bottom bubbling technology is to set one or two rows of bubbling points on the pool bottom between the melting zone and the clarification zone of the glass melting furnace, thereby bubbling a certain pressure of gas into the kiln, and driving the surrounding glass liquid to move through the rising movement of bubbles without destroying the normal convection of the glass liquid, thereby promoting the clarification and homogenization of the glass liquid.
Advantages of Bubbling Technology
After bubbling, a circular liquid flow from bottom to top is added near the hot spot of the glass melting furnace, as shown in Figure 1, so that the heat convection formed by the hot spot is strengthened, which can effectively block the scum that has not yet melted from flowing to the clarification zone. The rising of bubbles drives the movement of the surrounding glass liquid and promotes the removal of bubbles in the glass liquid. The tumbling and stirring action of bubbling increases the temperature of the glass liquid at the bottom of the pool, strengthens the heat exchange between the glass liquids, can significantly improve the chemical uniformity and thermal uniformity of the glass liquid, improve the uniformity of glass products, and greatly reduce defects such as bubbles, stones and streaks in the products. Bubbling can also increase the discharge volume and save energy. In the production of various glass products, especially in the melting process of colored glass with poor heat permeability such as brown and green, the bubbling technology is more effective.
Structure and installation of bubbling nozzle
Because the temperature of the glass liquid at the bottom of the pool increases significantly after bubbling, the flow speed of the glass liquid near the nozzle is accelerated, especially the glass liquid in the immovable layer at the bottom of the pool is also involved in the flow, thus aggravating the erosion of the refractory bricks materials at the bottom of the pool near the bubbling point. If it is not handled properly, it is easy to cause leakage and shorten the kiln life. Therefore, the bubbling nozzle should be resistant to high temperature, erosion, high strength, and not easy to oxidize. Commonly used materials include platinum and platinum rhodium (as the head of the nozzle), heat-resistant steel, corundum, silicon dimolybdenum, metal ceramics, etc. The inner diameter of the bubbling nozzle is generally 1~3mm, and a number of small holes are generally opened on the nozzle, which is convenient for bubble formation and can prevent the glass liquid from flowing back into the bubbling nozzle. The nozzle refractory bricks should be made of 41 oxidation method AZS bricks with strong corrosion resistance. In addition, the two rows of pool bottom bricks before and after the nozzle bricks should be 50~100mm higher than other pool bottom bricks, and the nozzle bricks should be 50~100mm higher than the two rows of pool bottom bricks before and after, forming a stepped shape, as shown in Figure 2. The depth of the bubbling nozzle into the glass liquid is very important for bubbling. If it goes too deep, the stirring effect on the glass liquid is not strong enough, and the glass viscosity is low, and the glass liquid is easy to flow back into the nozzle during the bubbling interval; if it goes too deep, the erosion of the refractory bricks material at the bottom of the pool is too serious, which will affect the life of the melting furnace. The nozzle is generally 200~500mm higher than the pool bottom and 50~100mm higher than the nozzle brick to prevent the glass liquid from flowing too fast and scouring the bubbler nozzle and causing the bubbler tube to be blocked.
