Analysis of energy-saving technical measures for ceramic kiln
The kiln used in the modern building and sanitary ceramics industry has many advanced and effective technical characteristics. The main measures are as follows: 1. Clean high-energy efficiency energy improves the firing efficiency; 2. Uses fully automated control of high-speed nozzles; 3. A large number of lightweight insulating refractory materials; 4. Popular low-temperature fast-burning methods and other four aspect.
1. Clean energy improves the thermal efficiency of firing
At present, the burning of building sanitary ceramic products and clean high-heat-efficiency energy have become the mainstream of ceramic burning fuel. Throughout the history of ceramic firing at home and abroad, there are many types of energy sources suitable for firing ceramics, such as solid fuel, liquid fuel and gas fuel. They include firewood, coal, heavy oil, light oil, electricity, natural gas, liquefied petroleum gas and so on. As history advances, firing technology continues to improve, and some energy positions rise, while others are eliminated. For example, firewood and coal and other solid fuels used for firing traditional ceramic products have basically completed their historical missions in the production of building sanitary ceramics due to low thermal efficiency and serious environmental pollution. Heavy oil and liquefied petroleum gas have high calorific value, which facilitates rapid firing at low temperature. Especially, liquefied petroleum gas has become a popular energy type in the emerging building and sanitary ceramics industry. Due to the high calorific value of liquefied petroleum gas, the content of impurities in the gas is small, and it is easy to quickly heat up and cool down, which is very convenient for the low-temperature and fast burning process of ceramics.
he naked flame naked burning method is a remarkable achievement in the burning of building sanitary ceramics in the past 10 years. Its characteristic is the use of clean energy. As an advanced firing method, the open flame naked flame method has shown effects on the uniformity of kiln temperature, kiln volume, production intensity and unit energy consumption. Within a period of time. The open flame kiln temperature uniformity is high. This is because the product stack resistance of this firing method is small, the pressure in the kiln is reduced, and the negative pressure of the pre-heat belt is low, so there is little leakage of cold air. Therefore, a very good energy saving effect is achieved. The physical quality of the product has also been greatly improved. When the naked flame firing method is used, the volume production intensity of the kiln is high. Since the product does need to be placed in the casket, the wasteful heat consumption caused by indirect heat transfer is avoided. And because the product is directly exposed to the flame, it is very conducive to rapid heat transfer and firing. Because the temperature of the kiln is uniform, the heat transfer is rapid, the weight ratio of the kiln furniture to the product is small, the firing time of the open flame naked flame is much lower than that of the open flame cartridge burning method. Mingyan naked burning increases the loading density of the product because it does use saggers.
2. Adopt fully automatic control of high-speed nozzle
The use of clean energy is conducive to the innovation and promotion of isothermal, efficient and uniform combustion nozzles, and the advantage is that it greatly reduces energy consumption. The new fully-automatically controlled high-speed nozzle can reduce the temperature difference in the kiln due to the powerful injection system, quickly increase the kiln temperature, and achieve fast isothermal firing efficiency. Therefore, the energy saving of ceramic kilns will depend on the continuous improvement of new fully automated high-speed nozzles. Traditional kilns such as flame-retardant dew burning kilns can only form radiant heat transfer between product columns between solids, and can form violent thermal agitation and thermal circulation, thus reducing the thermal efficiency of firing. In addition, the uniformity of the kiln temperature in the kiln is also very poor. The low uniformity of the kiln temperature directly leads to different firing temperatures of the products and an increase in scrap rate. After the fully automatic control of the high-speed nozzle is adopted, due to the jetting effect of the burner, the air flow in the kiln is strongly circulated and the hot flame is violently disturbed, which is very beneficial to uniform and balance the temperature in the kiln. Many new kilns are now equipped with high-speed temperature adjustment nozzles in the pre-heating zone, which is more conducive to directly reducing the temperature difference between the upper and lower pre-heating zone in the kiln. Greatly improve the energy-saving effect of firing.
3. Adopt light heat insulation material
The advanced nature of the light-weight heat insulation kiln is shown in the light assembly type design according to the modulus, and then the high-temperature light-weight heat insulation and refractory materials are used for strict masonry. The lining of the kiln is made of high-temperature resistant ceramic felt, plus ceramic wool other thermal insulation boards, with a total thickness of 450 mm. The inner lining is light high-alumina brick, and the middle and outer sides are also made of ceramic wool, with a total thickness of 600 mm. The outer surface of the kiln wall is a metal plate. This design and production ensure the high temperature practicality and energy saving of the kiln. Because ceramic fiber has good thermal stability, it does deform melt during high-temperature firing, and because of its low thermal conductivity, low heat storage, low density, and light weight, it has a significant energy saving effect.
The roof of the light-weight heat insulation kiln is hung by Z-shaped fiber prefabricated blocks, which reduces the weight of the kiln body and increases the thermal insulation effect. A metal heat exchanger (accounting for more than 65% of the area of the kiln roof) is added to the kiln roof the nozzle and quench air are installed to preheat combustion air and quench air. The kiln wall is made of cast U-shaped refractory blocks (high aluminum, clay). The blocks are filled with refractory fiber cotton, and the outside is made of refractory fiber felt calcium silicon board, U-shaped blocks and external steel The frame is connected, this structure is relatively stable, the thermal stability is good and the energy saving effect is high. According to calculations, when the temperature of the inner wall of the kiln reaches 1250 ° C, the temperature of the outer wall of the kiln is only about 50 ° C, indicating that the kiln body has excellent sealing. The refractory materials on the kiln car are all made of refractory fiber materials, which also reduces the unnecessary consumption of thermal energy.
The fiber suspended ceiling energy-saving kiln of Australia General Company (Australian Company for short) has the characteristics of wide kiln body, large loading capacity and short firing cycle. The effective width of the kiln reaches 2.65 meters. Due to the large firing batch and high firing efficiency, the overall energy consumption of the kiln can be greatly reduced when firing at full load. At present, this kind of kiln has become one of the main types of kilns in many places in China through the introduction, absorption and digestion in China.
4. Universally implemented low-temperature fast-burning technical measures
At present, low temperature fast burning technology is increasingly used in building sanitary ceramic products. In the past 10 years. The firing temperature of ceramic glazed tiles has decreased 1180 ° C to 1200 ° C to about 1050 ° C to 1100 ° C. The firing temperature of sanitary porcelain has been reduced the previous 1300 ℃ to the current 1150 ℃ ～ 1200 ℃. According to ceramic thermal engineering calculation principles, the higher the firing temperature, the greater the energy consumption. According to this, when firing 1200 ° C to 1300 ° C, the energy consumed is about 40% of the total energy consumption for firing the product. In this way, the energy saving effect is very obvious. In addition to energy saving, the low temperature fast burning method can also shorten the production cycle and save manpower and material resources.
In addition to the special technical requirements for kilns, the implementation of low-temperature fast-burning technology must also develop and develop better ceramic raw materials suitable for low-temperature fast-burning. At present, such raw materials include wollastonite raw materials, perlite raw materials, diopside raw materials, pyrophyllite raw materials, etc. In order to reduce the firing temperature and the cost of products abroad, red clay raw materials and purple sand raw materials with a large amount of iron are used in large quantities, and industrial waste materials are also used to make ceramic tile blanks. The products produced such raw materials are still covered by high-quality glazes, and they still have high selling prices. With regard to the use of inferior raw materials to produce high-quality ceramic tiles, IMHO, many ceramic companies in China are far doing enough.
Scientific and technological progress is promoting the development of the building sanitary ceramic industry, and the energy-saving work of product firing is becoming more and more important. This requires continuous improvement of the design level of new kilns, active research and development of new high-efficiency energy-saving refractory materials, continuous promotion of low-temperature fast-burning technology and other aspects of the work, so that the energy-saving technology of ceramic enterprises has continuously reached a new level.
3. Adopt light heat insulation material
The advanced nature of the light-weight heat insulation kiln is shown in the light assembly type design according to the modulus, and then the high-temperature light-weight heat insulation and refractory materials are used for strict masonry. The lining of the kiln is made of high-temperature resistant ceramic felt, plus ceramic wool other thermal insulation boards, with a total thickness of 450 mm. The inner lining is light high-alumina brick, and the middle and outer sides are also made of ceramic wool, with a total thickness of 600 mm. The outer surface of the kiln wall is a metal plate. This design and production ensure the high temperature practicality and energy saving of the kiln. Because ceramic fiber has good thermal stability, it does deform melt during high-temperature firing, and because of its low thermal conductivity, low heat storage, low density, and light weight, it has a significant energy saving effect.
The roof of the light-weight heat insulation kiln is hung by Z-shaped fiber prefabricated blocks, which reduces the weight of the kiln body and increases the thermal insulation effect. A metal heat exchanger (accounting for more than 65% of the area of the kiln roof) is added to the kiln roof the nozzle and quench air are installed to preheat combustion air and quench air. The kiln wall is made of cast U-shaped refractory blocks (high aluminum, clay). The blocks are filled with refractory fiber cotton, and the outside is made of refractory fiber felt calcium silicon board, U-shaped blocks and external steel The frame is connected, this structure is relatively stable, the thermal stability is good and the energy saving effect is high. According to calculations, when the temperature of the inner wall of the kiln reaches 1250 ° C, the temperature of the outer wall of the kiln is only about 50 ° C, indicating that the kiln body has excellent sealing. The refractory materials on the kiln car are all made of refractory fiber materials, which also reduces the unnecessary consumption of thermal energy.
The fiber suspended ceiling energy-saving kiln of Australia General Company (Australian Company for short) has the characteristics of wide kiln body, large loading capacity and short firing cycle. The effective width of the kiln reaches 2.65 meters. Due to the large firing batch and high firing efficiency, the overall energy consumption of the kiln can be greatly reduced when firing at full load. At present, this kind of kiln has become one of the main types of kilns in many places in China through the introduction, absorption and digestion in China.
4. Universally implemented low-temperature fast-burning technical measures
At present, low temperature fast burning technology is increasingly used in building sanitary ceramic products. In the past 10 years. The firing temperature of ceramic glazed tiles has decreased 1180 ° C to 1200 ° C to about 1050 ° C to 1100 ° C. The firing temperature of sanitary porcelain has been reduced the previous 1300 ℃ to the current 1150 ℃ ～ 1200 ℃. According to ceramic thermal engineering calculation principles, the higher the firing temperature, the greater the energy consumption. According to this, when firing 1200 ° C to 1300 ° C, the energy consumed is about 40% of the total energy consumption for firing the product. In this way, the energy saving effect is very obvious. In addition to energy saving, the low temperature fast burning method can also shorten the production cycle and save manpower and material resources.
In addition to the special technical requirements for kilns, the implementation of low-temperature fast-burning technology must also develop and develop better ceramic raw materials suitable for low-temperature fast-burning. At present, such raw materials include wollastonite raw materials, perlite raw materials, diopside raw materials, pyrophyllite raw materials, etc. In order to reduce the firing temperature and the cost of products abroad, red clay raw materials and purple sand raw materials with a large amount of iron are used in large quantities, and industrial waste materials are also used to make ceramic tile blanks. The products produced such raw materials are still covered by high-quality glazes, and they still have high selling prices. With regard to the use of inferior raw materials to produce high-quality ceramic tiles, IMHO, many ceramic companies in China are far doing enough.
Scientific and technological progress is promoting the development of the building sanitary ceramic industry, and the energy-saving work of product firing is becoming more and more important. This requires continuous improvement of the design level of new kilns, active research and development of new high-efficiency energy-saving refractory materials, continuous promotion of low-temperature fast-burning technology and other aspects of the work, so that the energy-saving technology of ceramic enterprises has continuously reached a new level.
