1 Current status of coal preparation technology in China 1.1 High-efficiency heavy medium coal preparation technology Heavy medium coal preparation equipment mainly has two types of lump coal heavy medium sorting machine and heavy medium cyclone. The maximum weight of heavy medium coal is 300-500 mm, the lower limit of separation is generally 13 mm, which is higher than that of cyclone; the lower limit of heavy medium cyclone is 0.2~0.15 mm; The lower diameter of the small diameter heavy medium cyclone can be up to 0.05 mm; it has the advantages of high sorting precision, strong adaptability to coal quality, and automatic control. At present, China's heavy medium coal preparation technology has made breakthrough progress. The simplified heavy medium coal preparation process with large pressureless feedstock three-product heavy medium cyclone as the main equipment has been widely used in society. China's current heavy medium coal preparation technology is very close to the world's advanced level. 1.2 Microbubble flotation technology For example, the compressed air microbubble flotation machine jointly developed by Zhuzhou Coal Preparation Plant and Tianzhuang Coal Preparation Plant uses the principle of air extrusion and discharge to enhance the microbubble mineralization process by using air force. 1.3 Fine coal dewatering technology In order to ensure the smooth development of coal preparation technology in China, China is actively researching pressure filtration technology, strong pressure flow-through pressure filtration technology and sedimentation centrifugal dewatering technology to realize the new development of fine coal dewatering technology. 1.4 Wind selection, moving screen and jigging Wind selection, moving sieve jigging and single-stage jigging coal preparation technology are mainly promoted in large areas in China's western regions where water shortage is lacking. The promotion of compound dry sorter and moving sieve jig has reached a certain amount. Gansu Jingyuan Mining Bureau adopted single-stage jigging technology and achieved good results. 1.5 Online Ash Measurement Technology Online ash is an indispensable technology in the coal preparation process and is now being promoted. The application of online ash meter and advanced metering technology provides a good development condition for China's coal preparation process. 1.6 Application of automation and computer technology in coal preparation plant At the same time of the development of coal preparation technology, advanced science and technology can be used to automate the entire coal preparation process. Computer technology not only facilitates production development, but also manages the entire production technology. China's large-scale coal preparation plant can be automated in all production processes including single-machine automation of jigs. 1.7 Automatic loading technology This technology has been widely used in large coal preparation plants and collection stations, which not only saves time for coal loading, but also ensures the safety of the loading process. 1.8 assembled coal preparation plant The assembled coal preparation plant mainly has the advantages of small investment, small use area and short construction time. It has been rapidly promoted and used in China since 1995. By 2004, more than 100 factories have been built or put into production in China, and more than 200 million tons of coal can be supplied each year. The amount of coal selected in China at this stage has been greatly improved. It is particularly noteworthy that the coal preparation plant built after 2000, such as the thermal coal preparation plant of Shenhua Group Shendong Branch, has a total staff efficiency of about 1 000 tons. 2 Problems in China's coal preparation industry 2.1 Poor environmental awareness and low utilization rate of by-products Due to the late start of China's coal preparation industry and weak foundation, the overall coal washing and total by-product production and environmental capacity are not balanced. The environmental awareness, energy and efficiency awareness of each coal preparation plant needs to be improved and improved. Generally speaking, China's coal enterprises have poor product quality awareness, environmental awareness and energy conservation awareness. 2.2 Insufficient research and development capabilities of coal preparation technology In the past, China's coal preparation technology and equipment research and development bases were mainly concentrated in colleges and universities, but did not achieve good results. At present, China's coal preparation technology and the lack of preparation for research and development have begun to stagnate. The sluggish development of the coal industry has caused various scientific research institutions to stop research on this technology. China's modern coal preparation enterprises have not carried out effective coal preparation technology renewal and equipment research and development. The private sector is indeed faced with a shortage of talent; state-owned enterprises are fully staffed but lack funds. 2.3 Low level of technical equipment China's modern coal preparation enterprises are all implemented centralized management, and very few manufacturers can achieve direct control. The automation of heavy medium sorting machine has been realized, and the single machine automation and flotation automation of the jig have yet to be improved, especially the online automatic detection technology. Only a few manufacturers are using it, and the overall level is still far from the world advanced level. 2.4 Poor reliability of equipment The reliability of domestic coal preparation equipment is poor. At present, the reliability of large-scale vibration equipment in China is generally poor, mechanical operation failures are more, and the service life is not long. For vibrating screens with a screen area of ​​more than 18 m2 and centrifugal vibrating dewatering machines of Φl300 mm and above, the normal operation is generally 1000 h, and the equipment overhaul period is less than 4 000 h; while the same type of equipment abroad can operate normally 3 000 h or more, overhaul period is more than 20,000 h. 2.5 Low industrial concentration and poor manufacturing quality At present, there are hundreds of coal preparation equipment manufacturers in China, but there is a serious shortage of large-scale professional coal preparation enterprises. The overall industry is not concentrated, and the scale of each factory is also small. China's current technology is relatively large, and the strong coal preparation equipment manufacturers are basically only Shandong Tai'an and Laiwu two coal mining plants, most of which are small private enterprises. China's coal washing and processing equipment manufacturing enterprises generally have problems such as backward processing methods, low quality of employees, poor management, poor research and innovation capabilities, low product varieties, poor quality and low reliability. Moreover, market competition is not standardized and vicious competition is intensifying. 2.6 Imperfect policies and regulations China started late in the coal preparation process, the foundation is weak, and the social policies and regulations are not perfect. There are no relevant incentive policies and regulations for the selection of thermal coal washing, especially for the selection of coal. In terms of environmental protection regulations, although the state has made some regulations on the indicators of pollutant discharge, it still lacks refined emission standards. The supervision and implementation of production is insufficient. In particular, the execution of rewards and penalties is insufficient, and it cannot effectively promote the washing of thermal coal and the use of post-selected thermal coal by users. In transportation, the classification and transportation of various coal preparations have not yet been realized, and the price is unreasonable, and the freight rate is too high, which seriously restricts the enthusiasm of the coal preparation enterprises. 3 Factors restricting the development of coal preparation technology in China 3.1 Market reasons The fact that China's modern industrial development tells us that the coal industry is getting more and more prosperous, requiring us to further develop the coal preparation process, and also provides a broad market prospect for the production of coal preparation equipment. Many small enterprises that do not have the technical ability also value the profits, and have entered the industry of coal preparation equipment production. As a result, many unqualified products have emerged, which has led to vicious competition in the coal preparation equipment market. The production of coal preparation equipment itself has high technical content and high design and manufacturing cost, but the vicious social competition makes China's qualified coal preparation equipment lose its original profit and market space, making the coal preparation equipment production enterprises unable to carry out new coal preparation technology and equipment. Research and development. 3.2 Institutional reasons For a long time, China has implemented a system in which research institutes engaged in scientific and technological development are separated from production enterprises engaged in equipment manufacturing. Research institutes with technical production capacity are out of line with production, sales and competition, and manufacturers that are closely related to market sales do not have corresponding production capacity. After the reform, the scientific research institutions need insufficient scientific research funds, they are eager to create profits for the enterprise, and the real research work is at a standstill. The R&D team with the enterprise as the main body has not yet been established, and there is a serious lack of research and development capabilities, and it has lost the technical support of the research institutes under the traditional system. Therefore, before and after the restructuring, there is no real change in the existing separation system. This situation has caused insufficient research and development capabilities of China's coal preparation technology and equipment, which has seriously restricted the development of China's coal preparation technology and equipment. 3.3 Talent reasons China lacks the support of talents in the production, use and management of coal preparation. Due to lack of technology, the decision-makers were not strong in command, and the introduction of advanced technology and equipment was unilaterally restricted, which restricted the development of coal preparation technology and equipment. In addition, the downturn in the coal industry in the 1990s also caused the major universities in China to pay less attention to the coal preparation profession. The number of students who actually entered the coal preparation profession has gradually decreased, and fewer people can truly engage in coal preparation. The situation of the coal preparation profession has gone from bad to worse. As a result, some colleges and universities have canceled the coal preparation profession. This situation has further increased the shortage of reserves of talents in China's coal preparation and the phenomenon of talents' faults. 3.4 Reasons for funding In the past, the funds for research institutes engaged in the research and development of coal preparation technology and equipment in China were funded by the state. After the restructuring, the research institutes were transformed into self-financing and self-developing enterprises. The national research grants have been abolished, which has made most research institutes have tight research and development funds. They can only use the main energy to develop the market and generate income for the enterprise. There is neither economic strength nor motivation to select coal with high investment, high risk and slow effect. Research and development of technology and equipment. 4 Development trend of coal preparation technology 4.1 Large-scale coal preparation equipment The scale of China's coal preparation plant is constantly increasing, and it has already developed into a large-scale coal preparation. In addition to the completion of the Shanxi Pingyi Antaibao Coal Preparation Plant (15 Mt/a) and the Anjialing Coal Preparation Plant (21 Mt/a) and other large coal preparation plants, most of the coal preparation plants under construction are larger than 6.0 Mt/ a, part of which is greater than 10 Mt/a, Beijing Huayu Engineering Co., Ltd. is designing the Inner Mongolia Shenhua Harwusu Coal Preparation Plant to be 25 Mt/a. The premise of the large-scale coal preparation plant is mainly determined by the large-scale coal preparation equipment. The use of large-scale equipment is conducive to the simplification of the system for coal preparation, as well as reducing personnel investment and increasing production efficiency. 4.2 Heavy medium technology dominates the market As China's economic strength continues to increase, new demands are placed on the quality of coal use, but the choice of coal in China is more difficult. The general trend of the coal preparation method is: heavy selection will be the main position, jigging is still the first choice for easy coal selection, the upper limit of flotation size will be reduced to about 0.2 mm, and the rest of the coal preparation technology can be used at specific times. . The improvement of automated production technology makes the modern coal preparation operation easier and easier, while reducing coal consumption and saving resources. The heavy medium coal preparation method has become easier to operate, is no longer as difficult to control as before, but is commonly used as the jigging method. Since the capital investment and production cost of heavy medium coal preparation have been close to the jigging coal preparation, and the precision and strength of coal preparation are higher than it, the heavy medium coal preparation method will dominate. 4.3 Development of fine coal dewatering technology By promoting the currently developed pressure filtration technology, high pressure flow-through pressure filtration technology and sedimentation centrifugal dewatering technology, the application of a 120 m2 pressure filter and a 400 m2 high pressure flow-through filter press achieved fine coal Further research on dehydration technology. 4.4 Assembled to become a new model for coal preparation plant construction China is in a new stage and a new era in the technical reform of a coal preparation plant. The new coal preparation plant to be built in the future is mainly a thermal coal plant to alleviate the current problems of coal use and coal quality. With the changes in market requirements and people's perceptions, the thermal coal and coking coal preparation technology has gradually merged into one. It is no longer necessary to distinguish coking coal or thermal coal in the design. The assembly coal preparation plant mainly realized “reducing construction time, reducing construction investment, reducing production cost, improving production efficiency and improving economic efficiencyâ€. Starting from the requirements of engineering construction, research, innovation and integration of a series of high-efficiency coal preparation technologies, got a good result. After continuous improvement by technicians, the assembly coal preparation plant will be the development goal of China's future coal preparation plant. 4.5 Automatic control of coal preparation process and whole plant automation Strengthen the application of mechatronics technology in large-scale screening machines, large-scale jigs, large-scale heavy medium cyclones, large-scale flotation machines, large-scale horizontal vibration centrifugal dewatering machines, and pressure filters, and continuously improve the level of automation. 4.6 Improve traditional coal preparation methods and improve equipment reliability To achieve the reliability of the equipment, only relying on high-tech technology, the automatic jig will enter the practical stage, and gradually become intelligent; heavy media, flotation will be matched with the product quality control system; through strengthening the equipment structure And use wear resistant materials to achieve equipment reliability. 5 Conclusion With the development of domestic coal washing technology and the increasing pressure of domestic environmental protection, we believe that China's coal washing process and coal washing technology can catch up with the world's advanced level in the foreseeable future. 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According to statistics, China's "Eleventh Five-Year" period, coal production and consumption is about to increase to 2.5 billion t, to 2020, when may reach 3 billion t. In order to make more efficient use of coal resources, protect the ecological environment, alleviate tensions railway transport, the state should vigorously advocate the development of coal preparation industry, so our future coal preparation industry will have a very bright future. The development of coal preparation industry is inseparable from professional coal preparation equipment, but from the actual situation, China's current coal preparation technology has not yet reached the advanced level. Since the reform and opening up, although China has achieved good results in the research and development of large-scale three-product heavy medium cyclone, microbubble flotation column and other coal preparation equipment; however, because China's production technology is still in its infancy, production technology is not Mature, the equipment market is basically occupied by foreign manufacturers. The backwardness of coal preparation equipment is the biggest reason for the backwardness of China's coal preparation industry. It is undoubtedly of great significance for the development of coal preparation industry to seriously analyze the various reasons behind the backward development of China's coal preparation industry.