Discussion on several energy saving ways of glass

Discussion on several energy-saving ways of glass furnace

the main energy consumption part in glass factory is glass furnace (its energy consumption accounts for more than 75% of the total energy consumption). Therefore, it is urgent to pay close attention to the energy conservation of glass kilns. Over the past few years, we have taken many energy-saving measures in the aspects of glass frit, charging system, combustion system, kiln structure, kiln body insulation, waste heat utilization, operation control and so on, and achieved great results. The fuel consumption index of many plants has decreased significantly. Some factories have reached the level of first-class furnaces or special furnaces. But compared with foreign countries, there is still a big gap.. So we have to work hard to further reduce energy consumption. Several energy-saving ways are proposed below:

leading, increasing the temperature of the liquid glass without increasing the flame temperature

after increasing the temperature of the liquid glass, the melting speed can be accelerated, the melting time can be shortened, and the output can be increased and the unit consumption can be reduced. The specific methods are:

(I) improve the radiant heat of the flame space to the liquid glass

1。 Liquid glass selectively absorbs radiant energy. The wavelength less than 3 microns can be transmitted downward through the liquid. The carbon particles in the flame and the inner wall surface of the kiln space can eject radiant energy with a wavelength of less than 3 microns. Therefore, increasing the blackness of the flame (by means of anoxic heat medium or carburization measures) and keeping the blackness value of the kiln Masonry High (related to the roughness and temperature of the masonry surface. The blackness value of clay brick and silica brick at high temperature is 0 at 1000 ℃. 0 at 62 ℃ and 1200 ℃. 0 at 53 ℃ and 1400 ℃. 49. The blackness value of electric melting refractory brick at high temperature is 0.. 5) can increase the radiant heat of the flame space to the liquid glass

2。 Eliminate the "cold air" film near the liquid level. Pay attention to the height of the bottom plate of the small furnace from the liquid level and the flame ejection angle. Oxygen blowing can also be considered as a melting aid measure (after oxygen blowing at the speed of meter/second abroad, the heat transfer speed is accelerated, and the flame temperature near the liquid level is increased by about 100 ℃)

(II) improve the temperature or temperature uniformity of the molten glass in the kiln pool

the view is to increase the heat transfer of flame to liquid glass by reducing the liquid surface temperature. When the liquid surface temperature decreases, the uniformity of the glass temperature in the deep direction of the pool is also improved. The measures to realize the above views are: 1. Bubbling at the bottom of the pool (pay attention to the purification of bubbling medium and the erosion of bubbling bricks). 2。 Deepen the pool. It can intensify the convection in the vertical direction and improve the temperature uniformity of the liquid glass on the pool depth. At the same time, it also adapts to the improvement of melting rate. 3。 Kiln body insulation. 4。 Electric melting aid

second, shallow clarification, deep reclaiming, control the liquid flow to flow in the direct direction of a single channel

this is from the point of view of increasing the temperature of the liquid glass in the clarification area, reducing reflux and selecting high-quality liquid glass to flow into the liquid hole. This can improve the output and quality of liquid glass and reduce the loss of reflux liquid glass. The measures taken to realize the above view are: setting low and wide kiln sill to reduce the sedimentation liquid hole below the clarifier (it can not sink when melting dark materials)

third, strengthen homogenization

most factories report that homogenization is the key to affecting product quality. For the specific selection of this equipment, please consult StarCraft technicians Cheng. At present, the homogenization process is basically in a state of "congenital deficiency and acquired imbalance". It is difficult to maintain the uniformity of the mixture after it is put into the kiln, resulting in uneven composition. The thermal permeability of liquid glass and the heat dissipation around the kiln cause uneven temperature. It is obviously not enough to rely solely on natural diffusion for homogenization. To this end, we must take measures to force homogenization. At present, effective measures include: low foaming in the pool (most obvious for dark materials), mixing in the material channel, discharging of working materials or at the bottom of the material channel (with leakage holes) and electric heating of the material channel. When adopting mixing measures, pay attention to the position of mixing point, the insertion depth of mixer and mixing process, otherwise the ideal effect will not be achieved. The material of domestic agitators is an urgent problem to be solved. The surface liquid flow can not only strengthen the transverse flow improve the temperature uniformity, but also pull away the dirty materials and crusts on the liquid surface. Ear size should be appropriate, do not cause too much heat loss, and the discharge can be continuous or intermittent. Electric heating can significantly improve the temperature uniformity in the deep direction of the chute, but it is expected that the temperature distribution on the horizontal plane may not be improved. The shape of electrode, the determination of liquid glass resistance between electric bases and the methods of electrode adjustment, installation and maintenance are the problems that should be paid attention to when heating. While taking measures of strong 1, load error exceeding ± 1.0% or unstable homogenization, we should still give full play to the role of natural diffusion. Therefore, the size of the working part and the length of the feeding channel should be carefully considered in the design

fourth, stable feeding

the stability of droplet shape, size and temperature is the premise to ensure molding quality and output. The separation degree between the feeding channel and the working part, as well as the section, size, thermal insulation, heating system and cooling system of the feeding channel are the main factors affecting the stable feeding. The complete separation between the feeding chute and the working parts can keep the chute in an independent operation system without interference. Some plants do not need to be completely separated, and the practice of heating the material path by the heat of the melting part is questionable. The cross section at the bottom of the material way is saddle shaped, which can reduce the transverse temperature difference. Properly deepening the material basin can increase the static head, so that the material drop temperature is more stable. The length and width of the material path shall be determined according to the flow volume and output. The longer material path is beneficial to the adjustment of temperature and can adapt to the change of material flow in a large range. The heat dissipation capacity of the material channel is very large, especially at the material basin. So we should strengthen the heat preservation. The heating and cooling system should be able to conveniently and reliably adjust the temperature of the liquid glass 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 the system combining gas heating with electric heating with multiple nozzles is ideal

fifth, reduce useless heat

(I) reduce unusable heat, such as heat dissipation on the surface of the kiln body, radiant heat from the orifice, heat carried away by gas escaping from the orifice and brick joints, etc. The measures taken are: 1. Kiln body insulation. The application of kiln body insulation in China has achieved remarkable results for several years. But it is only the primary stage, and the insulation effect can be further improved. The direction is to develop multi-layer combined thermal insulation layer, adopt composite (such as sandwich type and filling type) thermal insulation materials, develop loose concrete thermal insulation materials, and develop sealing materials supporting various refractory materials. 2。 Sealing of orifice and brick joint. Pay attention to the feeding port, temperature measuring hole, fire viewing hole, etc. If the processing properties, surface properties and mechanical properties of ultra-high activity polyethylene composites developed by Yangzi Petrochemical exceed the conditions of imported materials of the same kind, a fully enclosed feeder (such as spiral type and wrapped type) should be selected, corundum embedded tube should be used to measure the temperature, and industrial television should be used to observe the flame and chemical conditions. 3。 Large scale kiln. The larger the kiln scale, the lower the heat dissipation per unit output

(II) reduce the heat of repeated heating. It is mainly to reduce the heat consumed by the repeated heating of the reflux liquid glass (usually, this heat accounts for about one tenth of the heat consumed by glass melting). The measures taken include: setting up kiln sills, sinking the flow hole, appropriately reducing the height of the flow hole and appropriately reducing the glass temperature of the inlet hole

sixth, use the available heat

(I) fuel should be fully burned and all the heat should be released. Therefore, when burning oil, it is necessary to choose oil nozzles with good atomization effect (such as domestic GNB type internal mixing nozzles and imported machinery medium atomization composite nozzles from Japan, the United States and West Germany), adopt measures to strengthen atomization, and design small furnace structure and breast wall height that match the nozzles. When burning gas, it is necessary to determine the appropriate momentum ratio of air and gas, and make the air surround the gas

(II) improve the heat exchange efficiency and increase the air preheating temperature as much as possible. For this purpose, it is necessary to increase the heating surface area of lattice bricks, adopt higher lattice, and adopt novel lattice bricks and their arrangement (such as cross shaped and barrel shaped bricks, arranged into basket or chimney). It is also necessary to study the material of lattice bricks and the uniformity of air distribution in the lattice (the uniformity of air distribution is directly related to the utilization rate of lattice bricks. The factors affecting the uniformity of distribution include the construction coefficient of the lattice, the ratio of the upper and lower channel volumes of the lattice to the volume of the lattice, etc.)

(III) waste heat utilization of flue gas. The heat carried by the flue gas discharged from the regenerator should be recovered as much as possible under allowable conditions. Many factories set waste heat boilers in the flue system. Some factories have also installed heat pipes to recover heat. In addition, we should study how to use the waste heat of flue gas to heat or even sinter the batch

seventh, change the material formula and the spheroidization of the batch

(------ Professor Li Sheng Tong, University of Wisconsin, USA/director I) adding a small amount of fusing aid components into the material formula, such as lithium mica, can reduce the glass melting temperature and accelerate the glass melting. The discharge volume increased significantly

(II) spheroidization of batch. The shaping treatment of batch is a topic of concern. We advocate dry spheroidization. The mixture is pressed into small pellets without binder. It can eliminate the dust inside and outside the kiln, accelerate the solid-phase reaction, and increase the contact area between the batch and the liquid glass. In this way, the melting time can be shortened and the furnace life can be prolonged, and the unit heat consumption will also be reduced

eighth, use high-quality refractory materials and reasonable supporting

at present, it is recognized that all kinds of high-quality and durable refractory materials (such as capacitive refractories, zirconium, chromium, corundum, spinel and alkaline refractories, high-density, high-strength refractories, etc.) must be used and provided with reasonable supporting, so that the overall service life of the kiln can be increased synchronously. As we all know, the quality of furnace building materials is crucial to the kiln output, glass quality, fuel consumption and furnace life. Compared with foreign countries, there is still a considerable gap in the varieties, specifications and quality of refractories used in glass kilns in China. It is urgent to change this situation. We should also expand the use of high-quality refractory materials. In the long run, it is worthwhile to spend more on refractories. The energy-saving of glass kilns involves a wide range of areas, which requires the cooperation of many parties and joint efforts to achieve results

global glass () Department