Energy saving ways in the production of the hottes

2022-08-23
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Energy saving ways in the production of float glass

the glass industry is a high energy consumption industry. The glass furnace is the equipment with the most energy consumption in the glass production line, and the fuel cost accounts for about 35% - 50% of the glass cost The unit consumption of liquid glass in most float glass furnaces designed by China can reach 6500kj/kg ~ 7500kj/kg liquid glass, while the large float glass enterprises abroad only have 5800kj/kg liquid glass. We have a certain gap with the international advanced level

the thermal efficiency of glass furnaces in developed countries is generally 30% - 40%, while the average thermal efficiency of glass furnaces in China is only 25% - 35% One of the important reasons for this gap is the unreasonable structural design and thermal insulation measures of the furnace and the low quality of the refractory materials used. Secondly, the backward operation technology and imperfect management of domestic float glass process are also the reasons for high energy consumption, poor melting quality and short furnace life

so far, China has more than 140 float glass production lines, the glass production capacity has increased rapidly, and the market competition has gradually become white hot. As the main fuel of glass, the price of heavy oil continues to rise, accounting for an increasing proportion in the cost of glass. Therefore, reducing glass energy consumption is of great significance to reduce production costs, improve the market competitiveness of enterprises, reduce environmental pollution and alleviate energy shortages. Energy saving in glass enterprises is a long-term task, and technicians at home and abroad actively carry out research, such as optimizing furnace structure design, oxygen enriched combustion, full oxygen combustion, electric melting aid, heavy oil emulsification technology, etc. At present, many enterprises have begun to implement energy-saving measures in the production process, and explore energy-saving measures in the control of glass production process

it is well known that the moisture, temperature and fuel consumption of the batch. The state of moisture in the batch is closely related to the temperature of the batch, which is a very attractive trading point for many strategic buyers. When the temperature of the batch is greater than 35 ℃, most of the water is attached to the surface of refractory sand in a free state, so more soda ash can be adhered to enhance the melting effect. When the temperature of the batch is less than 35 ℃, the water in the batch will form Na2CO3 · 10h2o or Na2CO3 · 7H2O with soda ash, and Na2SO4 · 10h2o crystalline water compound with mirabilite, so that the sand surface loses water and appears dry, but because it has a variety of control modes, the fusing effect is weakened

in northern China, due to the low temperature in winter, the mix temperature is generally lower than 35 ℃, and in some areas, it is even only about 20 ℃. In order to keep the appearance of the batch moist, the method of increasing the moisture content of the batch is usually adopted. Although it plays a certain role, it will also bring many disadvantages, such as increased agglomeration on the silo wall, increased fuel consumption, etc. Someone calculated that the oil consumption of water entering the kiln was 0.085kg oil/kg water. Therefore, one of the means to reduce heavy oil consumption is to increase the batch temperature and reasonably control the water content. In order to ensure that the temperature of the mixture is always greater than 35 ℃, the way of adding hot water or steam into the mixer can be adopted. At the same time, the insulation of the belt gallery should be done well and the heating facilities should be added

proportion of broken glass broken glass is an inevitable product of glass production and an indispensable glass raw material. Broken glass and batch are mixed evenly in a certain proportion and added to the furnace, which can play a better role in helping the melting. According to the introduction, it takes about 1460kj heat to melt 1kg broken glass and raise the temperature to 1500 ℃, while it takes 2300kj ~ 2510kj heat to melt the same amount of soda lime silica glass. Therefore, using broken glass as much as possible within a reasonable range will have a certain effect on reducing fuel consumption. Through practice, it is considered that the proportion of broken glass in the furnace of 400 tons/day ~ 600 tons/day changes to 2%, and the oil consumption can be increased or reduced by 0.1 tons/day ~ 0.5 tons/day

reasonable melting temperature system a reasonable melting temperature system can not only improve the melting quality and reduce glass defects, but also achieve the purpose of saving energy, reducing consumption and improving kiln age

at present, there are generally three kinds of temperature curves of float glass furnaces, namely "mountain", "bridge" and "double height" curves. See Table 1 for temperature distribution and fuel distribution when different temperature curves are used The "mountain" curve is the temperature curve mainly used by domestic flat glass factories in the past. It is characterized by prominent hot spots, large temperature differences between hot spots and 1# small furnaces and end to end small furnaces, and the disadvantage is that it is difficult to make full use of the potential of the furnace. The "bridge" curve is similar to the "mountain" curve, which is characterized by a small difference between the temperature between the small furnace before and after the hot spot and the maximum temperature, and a long melting high temperature zone, which is conducive to improving the melting speed of glass batch and the clarification of glass liquid. The above two temperature curves are unfavorable to energy saving and furnace life

"double high" curve is the "double high heat load" temperature system, which is characterized by putting more fuel into the 1 # and 2 # small furnaces with more batch to strengthen the melting of batch; Reduce the fuel quantity of 3 # and 4 # small furnaces in the foam area and reduce the heat load here; Increase the fuel quantity of 5# small furnace to facilitate the clarification and homogenization of liquid glass at high temperature; 6. It is necessary to adjust the forming temperature. Because the "double height" curve distributes fuel reasonably, fuel consumption can be reduced. However, when adopting the "double height" curve, we must grasp the degree of concentration and dispersion of oil volume. Excessive concentration will aggravate the burning loss of the furnace

the comparison of the actual consumption of two temperature curves of a 600 ton/day furnace in a domestic plant verifies the above point of view. The consumption of "bridge" curve is 74.6kg/min, and the consumption of "double height" curve is 71.4kg/min. the sealing of the furnace has a great impact on the oil consumption. The expansion joints of various parts of the furnace generally need to be sealed after the completion of the kiln. If the sealing is not good, on the one hand, a large amount of heat energy will be emitted through these cracks, on the other hand, a large amount of external cold air will be sucked from the cracks between the pool wall and the breast wall, the flue, the regenerator and other cracks. Due to the clear contour of the indentation, fuel waste will be caused. The 400 ton/day float glass production line of a domestic factory has a fire phenomenon due to the large gap between the tank wall and the breast wall. At the same time, a large number of tank wall cooling air continuously enters the kiln through the gap, and the heavy oil consumption reaches about 83 tons/day. By sealing the tank wall gap, the heavy oil consumption is reduced to about 76 tons/day. This shows the importance of furnace sealing for energy conservation

the sealing of the furnace includes the sealing of the expansion joint of the kiln body, the sealing of the regenerator, the sealing of the flue, the sealing of the operation hole, etc., especially the sealing of the feeding port, between the breast wall and the pool wall, the regenerator and flue, and various observation holes

control of air volume in furnace combustion. The fuel can be completely burned only after being atomized by compressed air and mixed with a certain amount of combustion supporting air. If the amount of combustion supporting air is small, the fuel will burn due to insufficient oxygen

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