The bottleneck in the enlargement of key equipment for coal-based ethylene glycol production has been resolved

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Breakthrough in Overcoming the “Obstruction” to the Scaling Up of Key Equipment for Coal-Based Ethylene Glycol Production / Author/Source: China Chemical Industry News, Date: 10-23-2018, Clicks: 35 ——— Acceleration in the Adoption of Large-Scale Radial Tubular Water-Bed Hydrogenation Reactors A reporter from China Chemical Industry News learned yesterday from Yangmei Group Shenzhou Chemical Co., Ltd. that the company used a new type of radial tubular water-bed hydrogenation reactor developed by Nanjing Jutuo Chemical Technology Co., Ltd., which boasts complete independent intellectual property rights. This reactor was used to carry out technical upgrades to the hydrogenation B system of the company’s 200,000 tons per year ethylene glycol production facility; it was successfully put into operation on August 1 this year, and by August 7 the facility was operating at full capacity, with all parameters meeting the requirements specified in the process design. As of October 23, the device has been in continuous and stable operation for over two months. 　　Based on evaluations of industrial operation, one radial-bed hydrogenation reactor has now replaced the original two shell-and-tube reactors; this single reactor achieves the designed production capacity of 100,000 tons per year of dimethyl oxalate (DMO) for the production of ethylene glycol, with all the output meeting top-quality standards. The tower resistance is ≤ 22 KPa, which is less than half of that of the original shell-and-tube reactor. Temperature distribution ≤3°C. Once all aspects of the facility are optimized, it is possible to achieve an annual production capacity of 200,000 tons of ethylene glycol. Implementing technological upgrades to overcome bottlenecks: Liu Xiaofeng, chairman of Yangmei Shenzhou Chemical Co., Ltd., told reporters that in recent years, China’s ethylene glycol industry, just like that of synthetic ammonia and methanol, has entered a phase of building larger-scale production facilities. At present, the output of a single coal-to-ethylene glycol production unit in China has reached 300,000 tons per year. Well-known foreign companies such as Davy, Casale, and Topsoe, which are part of ICI, are all striving to enter the Chinese market. Almost all of the major technologies for producing methanol and ethylene glycol from coal are in the hands of foreign multinational corporations. 　　An Fu, deputy chief engineer and professor-level senior engineer at the Sinopec Group Corporation’s Economic and Technical Research Institute, told reporters that by the end of 2017, the global effective ethylene glycol production capacity was 31.68 million tons per year ； The production volume is 26.82 million tons per year, while the consumption volume is 27.05 million tons per year, showing continued rapid growth. By 2020, production capacity is expected to reach 40.51 million tons, while demand will be around 30.27 million tons ； By 2025, global production capacity is expected to reach 48.43 million tons, while demand is expected to be around 35.43 million tons. 　　An Fu said that in 2017, China’s ethylene glycol production capacity was 8.81 million tons per year, with a production volume of 6.13 million tons and import volumes of 8.75 million tons. The production capacity of ethylene glycol derived from coal accounts for 37% of the domestic total. It is estimated that by 2020, the additional production capacity of ethylene glycol in China will be around 8 million tons per year, with more than half of this coming from coal-based ethylene glycol production. By 2020, the production capacity is expected to reach around 11 million tons per year, with an apparent consumption volume of 15.2 million tons. 　　It is estimated that by 2025, China’s ethylene glycol production capacity will reach 14 million tons per year, with an apparent consumption volume of 17.5 million tons. Driven by rising international crude oil prices, China has seen a new wave of construction projects for coal-based ethylene glycol, with a clear trend toward larger-scale facilities. 　　Zheng Weizhong, a senior engineer at Shanghai Research Institute of Chemical Industry Co., Ltd. and secretary-general of the National Committee for the Development of New Coal Gasification Technologies, said that at present, China has achieved domestic production in key technologies related to coal-based ethylene glycol production, including process design, reactors, and catalysts; there are no critical constraints in this area. However, in terms of increasing the capacity of single reactors in the hydrogenation section, factors such as reactor structure, diameter, equipment transportation, and reactor resistance still interact with each other, limiting the amount of catalyst that can be loaded. The capacity of existing conventional shell-and-tube reactors abroad for a single tower is only 50,000 tons per year. 　　On the other hand, the large methanol plants currently being built in China (mainly those with a capacity of over 800,000 tons per year) all rely on foreign technology, with catalysts also being sold as complete packages. The syngas purification technologies required for large coal-based methanol plants are almost entirely under foreign control. Although domestic suppliers of complete sets of technology for coal-based ethylene glycol compete with foreign suppliers in this field, foreign companies hold a significant share in projects with a capacity of 400,000 tons per year; moreover, the process packages, core equipment, and catalysts are all sold as integrated packages. Both domestic and foreign technology suppliers have also realized that to enhance their competitiveness, it is necessary to achieve and overcome the challenge of enlarging core equipment such as reactors. Today, only Nanjing Jutuo Technology Company has achieved success in the research and development, manufacturing, and industrial application of larger-scale reactors for coal-based ethylene glycol and methanol production. 　　Liu Xiaofeng said that the DMO hydrogenation section of the company’s first-phase 200,000 tons/year ethylene glycol plant originally consisted of two series, A and B, with 2 reactors in each series; in total, there were four shell-and-tube hydrogenation reactors, namely A, B, C, and D. Since the shell-and-tube reactor operates with axial flow, the resistance is relatively high. The normal operating resistance of a single tower at the beginning of operation is 45–55 KPa; by the end of the catalyst’s useful life, this resistance rises to as much as 100 KPa. This results in the system resistance exceeding the design values, thereby affecting the safe and long-term full-load operation of the facility. 　　In this technical upgrade, while keeping the original process unchanged, a new radial tube bundle-type water-bed hydrogenation reactor developed by Nanjing Jutuo was adopted. Only the two shell-and-tube reactors in System B were replaced, and some pipelines were adjusted to fit. The upgraded radial reactor makes use of the bubbles from the original reactors, allowing for natural circulation of saturated water within the reactor. 　　Liu Xiaofeng said that the successful commissioning of this technical upgrade project marks the complete resolution of the \"bottleneck\" that has long hindered the scaling up of single reactors used in the production of ethylene glycol from coal in China. This, in turn, lays the foundation for the scaling up of single units and reactors used in coal-based chemical processes such as those for producing ethylene glycol and methanol. Identify the key pain points and make concerted efforts to address them. Wang Xuelin, general manager of Nanjing Jutuo Chemical Technology Co., Ltd., told reporters that in recent years, significant progress has been made in China’s coal-to-methanol synthesis technology. The domestically developed methanol synthesis reactors include the \"shell-and-tube external cooling-insulated composite reactor\" developed by East China University of Science and Technology, the \"gas-solid phase catalytic reactor\" produced by Hangzhou Linda Company, the \"water-cooled plate-type reactor\" manufactured by Nanjing Guochang Company, and the \"tubular water-bed methanol reactor\" developed by Nanjing Jutuo. Due to structural or heat exchange considerations, the capacity of each of these reactors in a single series is less than 600,000 tons per year. 　　Sinopec has also made significant progress in methanol synthesis processes and technologies. Sinopec Ningbo Engineering Co., Ltd. has a proven track record in the design of large- and medium-sized methanol plants. It has completed the design of medium-sized methanol plants in Golmud, Yumen, and other locations, as well as large-scale facilities such as the 770,000-ton/year methanol production plant from acetylene off-gas in Chuanwei, and the 850,000-ton/year natural gas-to-methanol plant operated by Chongqing Cabele. 　　The scaling up of coal-to-methanol/ethylene glycol plants places higher demands on the catalysts used in these processes. Ningbo Engineering Company has carried out design research on reactors in collaboration with Nanhua Institute and Nanjing Jutuo. On this basis, the three parties have collaborated on the research project of \"Development of large-scale radial water-cooled methanol synthesis reactor technology,\" aiming to provide support for Sinopec’s efforts to scale up MTO technology. This effort helps to break foreign technological monopolies in methanol production facilities with a capacity of 600,000 tons per year or more, promotes the localization of large-scale methanol/ethylene glycol production technologies, and facilitates the use of domestic catalysts in such facilities. 　　Wang Xuelin said that large-scale methanol synthesis towers are divided into two categories: one is the shell-and-tube axial flow reactor, and the other is the radial flow reactor. Axial flow reactors are limited by gas resistance, so the bed height cannot be too high (the effective section generally does not exceed 7 meters). To achieve a methanol production rate of over 600,000 tons per year, it is necessary to use catalysts with a large capacity; the diameter of axial flow reactors must be over 4.6 meters, which exceeds the practical limits for land transportation and thus **increases transportation costs**. On the other hand, due to the large diameter and high pressure, the tube sheet sizes of shell-and-tube reactors are becoming increasingly larger and thicker (some even exceeding 500 millimeters), which **increases the costs associated with purchasing and machining the tube sheets ； Therefore, radial flow should be given priority for efficient large-scale reactors. 　　Radial flow reactors manufactured by some domestic manufacturers, due to their smaller heat exchange surface area and poor heat transfer capabilities, are not suitable for domestic catalysts, which thus limits their development towards larger scales and their industrial application. 　　Nanjing Jutuo Technology Company has carefully studied and analyzed the current technical status of similar reactors both domestically and internationally. It has made significant efforts to mobilize its research capabilities to focus on research related to methanol and ethylene glycol reactors and systems, as well as on the development and dissemination of new technologies. As a result, it developed a reactor known as the \"tubular water-bed reactor,\" for which it obtained a **patent. Through continuous technological research and development and market promotion, the company has achieved considerable results. 　　Lu Jian, Chairman and Chief Engineer of Nanjing Jutuo Technology Co., Ltd., told reporters that after extensive fundamental research and innovation, Jutuo Technology has developed a “radial bundle-tube type aqueous-bed hydrogenation reactor” suitable for DMO hydrogenation reactions involving ethylene glycol. This development builds upon the industrial application of the company’s independently developed methanol bundle-tube aqueous-bed reactor. The new reactor has also seen multiple successful industrial applications, breaking through the limitations associated with the large-scale implementation of single-series, single-reactor shell-and-tube reactors. This achievement marks a pioneering step in this field within China. 　　Lu Jian said that the \"tube bundle water bed reactor\" developed by Nanjing Jutuo Technology Company has achieved numerous technical breakthroughs and features: first, it adopts a tube bundle structure with a small tube sheet. It overcame various limitations such as the difficulty in processing large tube sheets and the challenges associated with assembly, thereby breaking through the bottlenecks that prevented the enlargement of equipment. Second, multi-dimensional bending of seamless pipes is used. Welding at right angles to the flat tube sheet improves welding reliability and reduces the amount of welding required, thereby achieving \"inherent safety\". 　　The bundle tube technology is a prominent feature of this reactor. It does not have a large tube sheet like that of shell-and-tube reactors or coil-type reactors ； It also does not have a multi-layered annular tube water-cooled reactor or a coiled tube reactor with such multi-layered annular tubes and full-position welding structures, nor does it have as many seal plate welds as a plate tower. Thus, its equipment can achieve \"intrinsic safety\" and improved reliability. 　　A distributed tube sheet structure is adopted to facilitate the achievement of absolute sealing of the reactor. Compared to other types of reactors, the amount of welding required is minimal – only the tube sheet needs to be welded to the tubes – and automatic welding can be fully utilized, ensuring excellent welding quality. 　　By using appropriate materials, a large amount of low-alloy steel, stainless steel, and other such materials were saved, thereby reducing investment costs. 　　The heat exchange components are made of smaller seamless steel tubes; there are no butt welds throughout the entire piping system, which makes quality control easier. This design eliminates the possibility of leaks in the reactor. 　　Third, it has a larger surface area for heat exchange, resulting in strong heat transfer capacity, and no power is required to circulate the hot water. Due to the uniform distribution of heat exchange tubes containing saturated water with high-speed flow within the catalyst bed, the water inside these tubes possesses strong heat storage and heat transfer capabilities. Outside the tube is a catalytic reaction bed. The heat exchange area provided by water pipes per cubic meter of catalyst is quite large. Inside the tube, hot water naturally circulates under the influence of gravity, utilizing the density difference between the incoming and outgoing water; this effectively removes the reaction heat. It can fully achieve natural circulation, facilitate efficient heat transfer, and provide precise control over the bed temperature. 　　Fourth, a radial flow is adopted, resulting in low resistance in the reactor bed. In the bundle-tube water-bed reactor, the reactive gas flows through the catalyst layer via “centripetal radial flow” and “centrifugal radial flow”. As the gas flows radially through the catalyst bed, it also sweeps across the water-tube heat exchange layer. Due to the short path and large radial area, the resistance is very low. During methanol production, the pressure drop is only about 0.1 MPa; for the ethylene glycol reactor, it is merely around 22 kPa. Compared to shell-and-tube reactors with axial beds, these values are significantly lower. This results in remarkable energy savings, and scaling up to larger sizes is quite feasible. 　　Fifth, all heat exchange tubes adopt a full-length three-dimensional bent tube structure to automatically eliminate thermal stress. 　　Wang Xuelin told reporters that the bundle-tube water-bed reactor developed by Nanjing Jutuo Technology Co., Ltd. has not only been successfully applied in the production of ethylene glycol via the hydrogenation of dimethyl oxalate, but also in the low-pressure synthesis of methanol from syngas and in the water-gas shift reaction. To date, 5 units (manufacturers) have put this new type of reactor into use in the methanol synthesis sector: Jiangsu Jinmei Hengsheng Chemical Co., Ltd., Yangmei Group Shenzhou Chemical Co., Ltd., Jilin Tonghua Chemical Co., Ltd., Shanxi Hongyuan Coal-Coke Chemical Co., Ltd., and Inner Mongolia Jiajing Polymer New Energy Co., Ltd. 　　There are 5 facilities (manufacturers) set to become operational soon: Wanhua Chemical Group Co., Ltd., Jiujiang Xinlianxin Fertilizer Co., Ltd., Xuzhou Weitian Chemical Co., Ltd., Ordos Jinchengtai Chemical Co., Ltd., and Shandong Runyin Bio-Chemical Co., Ltd. Among them, the operating methanol plant has a maximum pressure of 5.5 MPa in its largest reactor, with a production capacity of up to 600,000 tons per year. 　　There is 1 unit in operation in the field of isothermal transformation: Jilin Tonghua Chemical Co., Ltd. There are two sets of facilities set to be put into operation: two units at Longpeng Coal Development Co., Ltd. in Qitaihe City, Heilongjiang Province, and one unit at Shandong Runyin Biochemical Co., Ltd. 　　In the field of coal-based ethylene glycol production, there is one plant that has already put into operation a process for producing ethylene glycol via the hydrogenation of dimethyl oxalate: Yangmei Group Shenzhou Chemical Co., Ltd. 　　The experience from the reactors of methanol plants with a structure similar to that of ethylene glycol, which have been successfully put into operation as mentioned above, demonstrates that the tubular bed reactor is fully suitable for achieving the goals of larger scale, radial flow, low resistance, high specific cooling area, strong heat transfer capacity, use of domestically produced catalysts, industrialized manufacturing, and intrinsic safety. Multi-party collaboration for continuous development. Wang Xuelin told reporters that Nanjing Jutuo Company is a private high-tech enterprise of ** level; it holds dozens of patented technologies in areas such as ammonia synthesis, shift reaction, low-pressure methanol production, and ethylene glycol production. Among these are various ** invention patents, including those for \"Fixed-bed catalytic reactor,\" \"Tubular water-bed reactor,\" \"Quasi-full-radial fixed-bed reactor,\" \"Tubular water-bed heat-transfer composite CO shift unit,\" \"Vertical modular isothermal reactor,\" \"Quasi-full-radial reactor,\" \"Baffle-rod type bellows heat exchanger,\" and \"Ammonia-cooled combined heat exchanger.\" “The Tubular Water-Bed Methanol Reactor and Related Process Technology” and “DC-Energy-Saving Ammonia Synthesis Reactor and Process System” have been recognized as **advanced and applicable technologies for energy conservation and emission reduction during the 13th Five-Year Plan period”. 　　Wang Xuelin said that as coal chemical plants such as those for producing ethylene glycol from coal become increasingly larger, there is an ever-growing need for larger reactor units. Nanjing Jutuo Company has established strategic partnerships with well-known domestic universities, research institutions, and key enterprises in areas such as ammonia synthesis, methanol, and ethylene glycol, in order to carry out joint research efforts. 　　The company has successively signed strategic cooperation framework agreements with Beijing Sanju Environmental Protection Technology Co., Ltd.; the two parties have agreed to carry out extensive and in-depth cooperation in areas such as ruthenium-based ammonia synthesis ； Strategic cooperation agreements were signed with Beijing Sanju and Sanjufuda to carry out research in areas such as pressure-equilibrium ammonia synthesis and ruthenium-based ammonia synthesis; in December 2017, an industrial-scale test of 30,000 tons of ruthenium-based ammonia synthesis was successfully conducted in Jiangsu. 　　The company has also signed a strategic cooperation framework agreement with Shanghai Pujing Chemical Technology Co., Ltd.; the two parties have agreed to carry out extensive cooperation in areas such as ethylene glycol carbonylation and the development of large-scale reactors for ethylene glycol production ； In May this year, both parties completed the testing of an industrial-scale unit for a 30,000-ton fully radial carbonylation reactor at a factory in Shanxi ； The first radial carbonylation reactor in the country, developed through joint efforts by both parties, is set to be launched on the market soon.