When was Tianye’s 5-megawatt coal-based acetylene plant built?

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This post was last edited by sunjl1981 on 2013-1-6 at 23:52. Acetylene, known as the \"mother of organic chemistry,\" is one of the most fundamental raw materials for organic chemical products in the world today. After 1970, due to the rapid development of the petrochemical industry, acetylene, which served as a basic raw material for organic products, was gradually replaced by cheaper ethylene and propylene. However, in recent years, with the rising costs of producing ethylene through naphtha cracking and the shortage of petroleum resources, the processing routes that rely on ethylene as a basic raw material have faced significant challenges, leading to a resurgence in acetylene-based chemical industries. 　　 Among the downstream products of coal chemical industry, coal-to-methanol is of particular interest to the industry, as well as dimethyl ether, ethylene, propylene derived from methanol, and coal-to-oil. Jin Yong, an academician of the Chinese Academy of Engineering and professor in the Department of Chemical Engineering at Tsinghua University, believes that coal-to-acetylene production can be achieved through a single reaction step; it represents one of the shortcuts in coal chemical processing and deserves attention. In light of this view, a journalist recently conducted an exclusive interview with Academician Jin Yong. 　　 Pilot-scale technology has been approved. Reporter: In the coal chemical industry, attention is often focused on methanol and its downstream products; why do you view coal-based acetylene in a different light? 　　 Jin Yong: Some time ago, people paid more attention to coal-based ethylene and propylene, but this route is quite lengthy. First, gasification takes place, followed by the synthesis of methanol; to go further, at least three or four chemical reactions are required, along with separation processes as well. Coal-to-acetylene production can be achieved in a single step, offering a more direct route, smaller equipment, and acetylene possessing activity no less than that of ethylene. I believe coal-based acetylene is a shortcut in coal chemical industry. 　　 Reporter: Acetylene is usually produced by the calcium carbide method; how is acetylene produced from coal? 　　 Jin Yong: Currently, acetylene is mainly produced using limestone and coke via the calcium carbide process, but this method has many problems: one of them is the high energy consumption. Because limestone and coke need to be melted in an electric furnace to a molten state to form calcium carbide, which then reacts with water to produce acetylene. The calcium in limestone does not end up in the product, but it needs to be melted during the production of acetylene, which requires a large amount of electrical energy ； Secondly, waste such as calcium carbide slag is generated, along with wastewater and waste gas. To solve the above problems, it is necessary to consider producing acetylene directly from coal without the need for limestone or calcium carbide. 　　 Of course, if acetylene is to be produced directly by hydrogenating coal powder, the coal powder needs to have a high level of activity. Therefore, plasma technology is considered; that is, a hydrogen plasma with an average temperature of 5000°C is generated using a plasma torch, and coal powder is then injected into it to directly produce a mixture of acetylene, hydrogen, carbon monoxide, etc. After separating and concentrating this mixture, high-quality acetylene can be obtained. In the 1990s, China attempted to introduce this technology from Russia, but the cooperation failed and was abandoned. 　　 Later, Tsinghua University, Fudan University, and **Tianye Group collaborated to develop a plasma-based coal pyrolysis technology with independent intellectual property rights. In 2006, an experimental plant for producing acetylene via this method was built, with a maximum torch power of 2 megawatts; it was capable of producing 1,600 tons of acetylene per year. After the basic success of this device, a plasma-based coal-to-acetylene plant with a maximum torch power of 5 megawatts was built in recent years, capable of producing 4,000 tons of acetylene per year. 　　 Of course, this device also encountered problems during development, mainly the reaction reactor tended to get clogged. Due to temperature fluctuations, the coal gangue in coal melts and sticks together. The main problem caused by this issue is that the driving time is relatively short, resulting in the reactor getting blocked in a very short period of time. After technical efforts were made, this issue has now been completely resolved. A 5-megawatt unit allows the vehicle to start driving whenever desired and to stop whenever desired. This set of core equipment passed the appraisal organized by the Construction Corps at **Tianye Group** in March. 　　 Theoretical benefits are considerable. Reporter: Then can plasma-based coal-to-acetylene production be brought to industrial scale? 　　 Jin Yong: Although the technology for producing acetylene from coal using plasma has been developed, this device is currently used mainly for experimental purposes. The coal preparation system located at the front and the separation and treatment units at the back are not yet fully developed; therefore, the coal powder system ahead of this setup needs to be expanded, and the separation and other post-treatment devices at the back must be upgraded as well. This will enable stable production of acetylene from plasma-based coal processing, allowing the product to be fed into larger systems such as those for vinyl chloride, thus enabling continuous operation. 　　 Overall, the core technology has now been developed; what remains is to improve the various auxiliary systems at the front and back end, integrate them into a larger system for stable and continuous production, and turn it into an industrialized technology. 　　 Reporter: Please analyze the economic benefits of using plasma-based coal-to-acetylene technology. 　　 Jin Yong: In principle, the plasma-based coal-to-acetylene technology eliminates the need for limestone; no molten limestone is required. According to calculations, it can reduce energy consumption by 30% to 35%. Since the main cost of this technology lies in electricity consumption, it reduces energy use by 30%–35% compared to the calcium carbide method, which translates to a theoretical cost reduction of 30%–35% as well. In this way, acetylene is no longer a high-energy-consuming industry. Although it is not yet very energy-efficient, it is at least not energy-intensive, making it an acceptable technology. At the same time, this technology does not generate waste residue, wastewater, or exhaust gas, making it a clean technology. 　　 In practice, since this system has not yet been connected to the larger system behind it and waste heat utilization has not been carried out, it is still not possible to calculate the specific benefits. Overall, I believe that producing acetylene from coal using plasma is technically feasible, and the theoretical economic benefits are considerable. The actual economic benefits will need to be calculated; once this system is in operation for a year connected to the grid, it will be possible to determine exactly how much energy can be saved. 　　 Reporter: What is the market potential for acetylene? 　　 Jin Yong: Currently, the derivatives of acetylene produced by the calcium carbide method mainly include polyvinyl chloride, chlorinated polyvinyl chloride, ethylene oxide, and vinyl acetate. Among them, polyvinyl chloride is the largest user of acetylene produced by the calcium carbide method, accounting for about 70% of the total consumption of acetylene produced in this way. By the end of 2008, 75% of China’s total PVC production capacity relied on the calcium carbide process. In 2008, the PVC production capacity was 15.81 million tons, representing a 9% increase year-on-year. Acetylene has many useful applications. 　　 　The devil can turn into an angel. Journalist: The main application area of acetylene is in the production of polyvinyl chloride, but the calcium carbide process for producing polyvinyl chloride has always been considered an outdated technique. 　　 Jin Yong: That’s right. In recent years, people have considered the use of coal to produce polyvinyl chloride to be a technology that must be phased out, viewing it as something evil. Because, first, it consumes a large amount of energy ； Second, there is the generation of \"three wastes\" ； Third, the catalyst used to produce vinyl chloride from acetylene contains mercury ； Fourth, the scale of the industry is very small; the production capacity of a single vinyl chloride reactor is only 5,000 to 7,000 tons. In plants that produce polyvinyl chloride using the calcium carbide method, individual \"round containers\" can be seen; those are the reactors. It is common for a factory to have thirty to fifty such small reactors. If each reactor has a production capacity of 5,000 tons, 200 such reactors would be needed to produce 1 million tons of polyvinyl chloride. How many instruments and personnel are needed to control it? This is the main reason why calcium carbide-based PVC cannot be produced on a large scale. Therefore, the industry previously believed that calcium carbide-based PVC should be replaced by ethylene-based PVC. 　　 However, due to the scarcity of oil resources in our country, there isn’t enough ethylene available for producing polyvinyl chloride; therefore, even though the calcium carbide method is considered problematic, we still have to deal with it and use it. At present, over half of China’s polyvinyl chloride is produced using the calcium carbide-acetylene method. 　　 It is worth noting that to completely transform the process of producing polyvinyl chloride from coal into a beneficial one, in addition to using plasma-based coal pyrolysis to produce acetylene, a fluidized-bed vinyl chloride reactor is also necessary. This is because the current calcium carbide process vinyl chloride synthesis furnaces are fixed-bed reactors with very low production capacity, ranging from 5,000 to 7,000 tons, and they use mercury-containing catalysts. Replacing the fixed-bed reactor with a fluidized-bed reactor not only allows for an increase in production capacity but also enables the reduction or even complete elimination of the use of mercury-containing catalysts. Because the original fixed-bed saw the reaction temperature hot spots move upward continuously throughout the operation cycle, which led to mercury sublimation and loss during the reaction, resulting in mercury pollution. The fluidized bed is an isothermal bed, so the sublimation loss of mercury is **reduced**, and mercury pollution can be significantly lowered. 　　 Since the catalyst in a fluidized bed can be continuously regenerated, there is no requirement for a service life when developing new catalysts. This expands the range of catalyst options, laying a solid foundation for the development of mercury-free catalysts. By using plasma-based coal-to-acetylene production in place of the calcium carbide method for acetylene production, and fluidized-bed vinyl chloride reactors instead of the conventional fixed-bed vinyl chloride reactors, it is possible to resolve all the issues related to pollution, energy consumption, mercury catalysts, and large-scale production associated with the process of producing polyvinyl chloride from coal. This approach addresses these four problems inherent in the current calcium carbide-based polyvinyl chloride production method at its source. 　　 Reporter: So what is the current progress in research and industrialization of vinyl chloride fluidized bed reactors? 　　 Jin Yong: At present, **Tianye Group has built 4 fluidized-bed vinyl chloride reactors, with each reactor having an annual production capacity of 100,000 tons. These reactors are currently in use and are performing well. Once this fluidized-bed reactor technology for vinyl chloride synthesis is perfected, it can be combined with the previous plasma-based method for producing acetylene, thereby enabling the transformation of the entire system used in calcium carbide-based PVC production. First, coal is converted into acetylene using plasma technology, and then vinyl chloride is synthesized in a fluidized bed reactor, enabling the large-scale production of polyvinyl chloride. We aim for a production capacity of 250,000 tons per fluidized bed reactor; thus, 4 reactors would be sufficient to achieve a PVC production capacity of 1 million tons. 　　 Reporter: The 5-megawatt plasma coal-based acetylene plant can now achieve an annual production capacity of 4,000 tons. Are there plans to increase this capacity further? Do you find this magnification task difficult? 　　 Jin Yong: I think scaling up the work is technically easier than doing it before, and after scaling up it becomes more stable technically, making it easier to implement. The 5-megawatt device is currently the leading one in the world, as well as the largest of its kind internationally. This technology in our country is still evolving, and we aim to further expand its scale; the next step is to reach capacities of over 15 megawatts. In this way, a single plasma acetylene furnace can achieve a production capacity of around 20,000 tons. The idea of building a 15-megawatt plasma coal-based acetylene furnace is under cold-test and computational evaluation, as well as pilot-scale testing. 　　 In the past, it was believed that coal-based PVC posed problems and was like a devil that couldn’t be used on a large scale; but due to its economic advantages, people had to embrace this \"devil\" anyway. Acetylene produced by plasma methods can replace that produced by calcium carbide methods, and fluidized beds make it possible to solve the problem of mercury catalysts, which will lead to thorough changes in the very large PVC industry. Of course, this will also take time. Many entrepreneurs and researchers are optimistic about this radical transformation and are working hard to make it a reality, hoping to successfully turn plasma-based coal-derived acetylene into polyvinyl chloride – this \"miracle material\" – within two to three years. It is a bright future. Of course, there is still a distance to go before true large-scale industrialization is achieved. 　　 Reporter: What other efforts are needed? 　　 Jin Yong: Research requires the cooperation of scholars. Additionally, it is necessary to find partner companies that meet the investment requirements and possess relevant coal resources. This technology requires relatively young coal types, that is, coal types with a high volatile matter content. In general, it is about combining resources, funds, and technology to fully achieve clean production from coal-based acetylene to polyvinyl chloride. # + + .