The energy consumption of the glass furnace accounts for more than 75% of the total energy consumption of the glass factory. In recent years, we have adopted a lot of measures in the aspects of glass material, feeding system, combustion system, furnace structure, kiln body insulation, waste heat utilization, operation control, etc. Energy-saving measures have achieved great results. The fuel consumption indicators of many plants have dropped significantly. Some factories have reached the level of first-class or special-class furnaces. But compared with foreign countries, there is still a big gap... On the issue of how to reduce energy consumption, several energy-saving approaches are proposed below:
Increase the temperature of the molten glass without increasing the flame temperature.When the temperature of the molten glass is increased, the melting speed can be accelerated, the melting time can be shortened, and the output is increased and the unit consumption is reduced. The specific method is:
1.Increase the radiant heat of the flame space to the molten glass.
(1) Liquid glass selectively absorbs radiant energy.
Wavelengths less than 3 microns can pass through the liquid surface downward. It is the carbon particles in the flame and the inner wall surface of the kiln space that can emit radiant energy with a wavelength of less than 3 microns. Therefore, increase the blackness of the flame (by hypoxia heat medium or carbon increase measures) and maintain a high blackness value of the kiln masonry (related to the roughness and temperature of the masonry surface. The blackness of clay bricks and silica bricks at high temperatures Degree values are: 0.61-0.62 at 1000°C, 0.52-0.53 at 1200°C, 0.47-0.49 at 1400°C. The blackness value of fused refractory bricks at high temperatures is 0.4-0.5), which can increase the flame space’s resistance to the molten glass Radiant heat.
(2) Eliminate the "cold air" film near the liquid level.
Pay attention to the height of the bottom of the small furnace from the liquid surface and the angle of flame spraying. It is also possible to consider the use of oxygen blowing to boost measures (after blowing in oxygen at a speed of 195-500 m/s abroad, the heat transfer rate is accelerated, and the flame temperature near the liquid level is increased by about 100 ℃).
2.Improve the temperature or temperature uniformity of the molten glass in the kiln.
The point of view is to increase the heat transfer of the flame to the molten glass by lowering the liquid surface temperature. While the temperature of the liquid surface is lowered, the uniformity of the temperature of the glass liquid in the depth of the pool is also improved. The measures taken to realize the above point of view are: (1). Bubbling at the bottom of the pool (pay attention to the purification of the bubbling medium and the erosion of the bubbling bricks). (2). Deepen the pool. The convection in the vertical direction can be intensified, and the uniformity of the temperature of the molten glass on the depth of the pool is improved. It also adapts to the increase in melting rate. (3). Kiln body insulation. (4). Electric boosting.
Most factories report that homogenization is a key process that affects product quality. At present, the homogenization process is basically in a state of "congenital deficiency and acquired disorder". It is difficult to maintain the uniformity of the mixed materials after entering the kiln, resulting in uneven composition. The heat permeability of the molten glass and the heat dissipation from the kiln to the surroundings caused uneven temperature. Relying on natural diffusion alone for homogenization is obviously unsatisfactory. For this reason, mandatory homogenization measures must be taken. The current effective measures include: low bubbling in the pool (obvious for dark materials), mixing in the material channel, discharge of the working material or the bottom of the material channel (with leaking holes) and electric heating of the material channel. When mixing measures are used, it is necessary Pay attention to the position of the stirring point he insertion depth of the stirrer and the stirring process, otherwise the ideal effect will not be obtained. The material of the domestic stirrer is an urgent problem to be solved. The surface liquid flow can not only strengthen the lateral flowimprove the temperature uniformity, but also pull away Dirty material and crust on the liquid surface. The size of the ear delay should be appropriate, so as not to cause too much heat loss. The discharge can be continuous or intermittent. Electric heating can obviously improve the temperature uniformity in the depth of the forehearth pool, but it is expected that the temperature distribution on the horizontal plane may not be improved. The shape of the electrode, the determination of the resistance of the liquid glass between the electric bases, and the method of electrode adjustment, installation, and maintenance are issues that need to be paid attention to when heating. While adopting compulsory homogenization measures, it is still necessary to give full play to the role of natural diffusion. Therefore, the size of the work section and the length of the forehearth should be carefully considered in the design.
Reduce useless calories
(1) Reduce unusable heat, such as heat dissipation from the surface of the kiln body, radiant heat from the orifice, and heat carried away by the gas escaping from the orifice and the brick joints. The measures taken are: 1. Kiln body insulation. my country has adopted kiln body insulation for several years, and the effect has been remarkable. However, it is only at the preliminary stage, and the heat preservation effect can be further improved. The direction is to develop multi-layer combined thermal insulation layer, use composite (such as sandwich type, filling type) thermal insulation materials, develop bulk concrete thermal insulation materials, develop sealing materials that are matched with various refractory materials, and so on. 2. The sealing of the orifice and the brick seam. Pay attention to the feeding port, temperature measuring hole, fire hole and so on. If conditions permit, use a fully enclosed feeder (such as screw type, wrap-in type), use corundum embedded tube to measure temperature, and use industrial TV to observe flame and chemical conditions. 3. Large-scale kiln. The larger the kiln scale, the lower the heat dissipation per unit output.
(2) Reduce the heat of repeated heating. The main purpose is to reduce the heat consumed by repeated heating of the refluxed molten glass (usually, this heat accounts for about one-tenth of the heat consumed by the melting of the glass). The measures taken are: setting up kiln ridges, sinking the liquid hole, appropriately reducing the height of the liquid hole and appropriately lowering the temperature of the molten glass in the liquid hole.
Shallow clarification, deep reclaiming, and control the liquid flow to flow in a single-channel direct current direction
This is from the viewpoint of increasing the temperature of the molten glass in the clarification zone, reducing backflow and selecting high-quality molten glass into the flow hole. In this way, the output and quality of the molten glass can be improved and the loss of the refluxed molten glass can be reduced. The measures taken to realize the above point of view are to set up short and wide kiln ridges to reduce the sinking liquid cave below the clarification tank (it does not sink when the dark material is melted).
Stable feeding system
The stability of the shape, size and temperature of the droplet is the prerequisite to ensure the quality and output of the molding. The degree of separation between the forehearth and the working part, as well as the cross-section, size, heat preservation, heating system and cooling system of the forehearth are the main factors that affect the stable feeding. The full separation between the forehearth and the working parts enables the forehearth to maintain an independent operation system without interference. Some factories do not need to be completely separated, and the method of heating the forehearth by the heat of the melting part is questionable. The saddle-shaped cross section of the bottom of the forehearth can reduce the lateral temperature difference. Properly deepening the material bowl can increase the static pressure head and make the temperature of the gob more stable. The length and width of the material channel should be determined according to the flow volume and output. Longer forehearth is beneficial for temperature adjustment and can adapt to changes in flow volume in a larger range. The heat dissipation of the material channel is very large, especially at the material bowl. Therefore, heat preservation must be strengthened. The heating and cooling system should be able to adjust the temperature of the molten glass flexibly and reliably, and maintain the uniformity of the temperature. The cooling system plays the role of coarse adjustment, and the heating system plays the role of fine adjustment. Most people think that a system that combines multi-nozzle gas heating and electric heating is ideal.
It is urgent to change this situation. We should also expand the use of high-quality refractory materials. From a long-term point of view, it is worthwhile to spend more on refractory materials. Energy-saving of glass kilns involves a wide range of areas and requires the cooperation and joint efforts of multiple parties to achieve results.