【Ten Years of Rapid Development in Chemical Equipment】1616–2024: Internationally Leading! The key technologies for high-quality hexamethylenediamine produced by the caprolactam method have been verified

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Happy May Day 2024 – safety first! **********************[A Decade of Progress in Chemical Equipment] Continuous updates and summaries available; feel free to join the discussions at https://bbs.hcbbs.com/thread-3576046-1-1.html (Source: Haichuan Chemical Forum Website) ***************** On April 23, 2024, it was learned from Jiangsu Yangnong Chemical Group Co., Ltd., a subsidiary of Sinochem International (referred to as Yangnong Group), that the scientific and technological achievement titled “Development and Industrialization of Key Technologies for High-Quality Adipic Acid Using the Caprolactam Method”, developed through collaboration between Yangnong Group, Xiamen University, and Ningxia Ruitai Technology Co., Ltd. (referred to as Yangnong Ruitai), was recently evaluated by experts organized by the China Petroleum and Chemical Industry Federation in Beijing. After the expert group led by academicians of the Chinese Academy of Sciences such as Yang Wantai and Qing Fengling completed the evaluation, they unanimously agreed that the high-quality adipic acid technology developed as a result of this project combines various advantages, enabling the stable production of high-quality adipic acid; the overall technology is at the international leading level. They approved the evaluation of this scientific and technological achievement and recommended that further efforts be made to promote its application. 　　According to Ding Kehong, General Manager of the Science and Innovation Center of Sinochem’s Chemicals Division, who presented a report on the achievements and a project status report at the appraisal meeting, a total of 87 patents were applied for for this achievement, of which 44 were granted. In April 2022, Yangnong Group built the world’s first 10,000-ton-per-year production facility for hexamethylenediamine using the caprolactam process at its wholly-owned subsidiary Yangnong Ruitai. In May of the same year, the industrial plant was successfully commissioned to produce 40,000 tons of nylon 66 and 25,000 tons of hexamethylenediamine per year; it has been operating steadily for two years now, producing high-quality hexamethylenediamine and nylon 66 products with high yields and low emissions of waste materials. 　　Academician Yang Wantai, head of the appraisal committee, noted that this project innovates the production process by using bulk chemicals such as caprolactam, ammonia, and hydrogen as raw materials. Through a fixed-bed continuous catalytic amination reaction, 6-aminocapronitrile is produced, which is then converted into hexamethylenediamine via a fluidized-bed continuous catalytic hydrogenation process. This has led to the development of a high-quality hexamethylenediamine production technique based on the caprolactam method, breaking the long-term monopoly held by multinational companies over the key technologies and supply of raw materials for nylon 66. Compared with traditional production processes, it also has advantages such as readily available raw materials, low investment, no use of highly toxic chemicals like hydrocyanic acid, and high levels of safety and environmental protection. 　　The expert group believes that the main innovation of this project lies in two aspects: first, it developed a coupled technology of \"hetero-element doping\" and \"in-situ hydrothermal strengthening,\" and utilized a soft-template strategy to create ammoniaation catalysts with high selectivity and high strength as well as multi-level pore structures, enabling a one-way service life of such catalysts exceeding 8,000 hours at high temperatures and a TON value of over 30,000 tons per ton. Second, based on the \"bimetallic synergistic hydrogen overflow mechanism,\" highly active hydrogenation catalysts were innovatively developed, which significantly increased the hydrogen dissociation rate and enhanced the intrinsic activity of the catalysts; the conversion rate of 6-aminocapronitrile exceeded 99.9%, while the purity of hexamethylenediamine reached 99.998%, surpassing that of similar international products. Secondly, efficient gasification technologies for caprolactam and high-throughput low-pressure distillation technologies were developed, addressing the coking problem associated with heat-sensitive substances such as caprolactam and 6-aminocapronitrile. Furthermore, a tar recycling technology was invented, enabling the efficient reuse of cyanide-containing coking residues and significantly reducing the consumption of caprolactam. Three inventions were made regarding the ammoniation reactor: the radial temperature difference within the bed layer is 5°C, resulting in high conversion rates of caprolactam and high selectivity for 6-aminocapronitrile. Another invention concerns a precise control method for the multiphase flow state in cyclic fluidized-bed hydrogenation reactors, which leads to lower catalyst consumption. 　　Ding Kehong said that, standing at a new starting point, Yangnong Group will insist on regarding technological innovation as the \"only option\" and \"top priority\" for achieving high-quality development. By building on key technological breakthroughs in caprolactam-based hexamethylenediamine production, the group will work to develop a range of nylon products and bring them to market. It will also focus on strengthening, supplementing, and extending the relevant industrial chains, aiming to become a leader in the modern nylon industry chain. In this way, it will contribute to Sinochem’s goal of addressing weaknesses in the field of chemical new materials and enhance China’s international competitiveness in this sector. 　　It is understood that the appraisal meeting was chaired by Li Wenjun, assistant director of the Science, Technology and Equipment Department of the China Petroleum and Chemical Industry Federation. Li Bin, vice president of the China Petroleum and Chemical Industry Federation, attended the meeting and delivered a speech. He noted that Yangnong Group is an outstanding enterprise that places great emphasis on technological innovation, with its business scope evolving from chlor-alkali-based fine chemicals to new materials and intermediates. This scientific and technological achievement possesses strong competitiveness and holds great significance for promoting technological advancement in the industry.