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Recently, the ethylene oxide/ethylene glycol (EO/EG) unit of the Fujian Zhangzhou Gulei integrated refining and chemical complex – the largest petrochemical project jointly developed by the two sides of the Taiwan Strait – was put into operation, successfully producing qualified ethylene glycol products. The equipment for the Gulei project features two of the world’s largest ethylene oxide (EO) reactors, manufactured using China’s own proprietary technology. The name of this technology is “Design, Manufacturing, and Maintenance of Critical Pressure Vessels under Extreme Conditions.” It has enabled the domestic development of the first units of 36 types of pressure vessels, breaking foreign monopolies and enhancing China’s ability to design and manufacture such critical pressure vessels independently. It has been widely applied in fields such as chemicals and gas processing, reaching international leading levels. Among them, the large EO reactor is the last static equipment in the large ethylene plant. The localization of large-scale EO reactors is a major scientific and technological achievement for Sinopec; it was designed by SEI and manufactured by Nanjing Chemical Machinery Co., Ltd. (hereinafter referred to as “Nanjing Chemical Machinery”). To date, 26 large-scale EO reactors have been manufactured, providing strong support for the transformation and upgrading of China’s petrochemical industry. Over 10 years ago, due to limitations in the level of domestic production, some important pressure vessels in our country forced us to rely on imports for a large number of key equipment needed for major construction projects such as those involving tens of millions of tons of oil refining capacity, millions of tons of ethylene production, and large-scale coal chemical industries. The construction of large-scale ethylene plants with production capacities of millions of tons, such as those at Tianjin Petrochemical and Zhenhai Refining & Chemical, encountered technical barriers imposed by foreign manufacturers, which put these projects at risk of suspension. Large EO reactors are crucial heat-transfer-enhancing reaction vessels in the ethylene industry; they have complex structures, large sizes, thick tube sheets, and the media involved are prone to stress corrosion. They require high technical standards and present significant manufacturing challenges, which has led to a reliance on imports in the past. Previously, these reactors were designed by American design firms and manufactured by Japanese companies, with most having a short service life. In 2006, an operating imported EO reactor at Shanghai Petrochemical developed irreparable problems, and the equipment continued to operate despite these issues. The group company has made up its mind to localize production. At that time, Yangzi Petrochemical was preparing to expand its capacity by building an ethylene oxide plant with an annual production capacity of 180,000 tons. The group company decided to use the localization of the EO reactors at Yangzi Petrochemical as an opportunity to promote the localization of key equipment in China’s petrochemical industry; relevant leaders even issued formal commitments in this regard. On April 20, 2009, Nanhua Company signed a contract with Yangzi Petrochemical for the manufacture of a large-scale EO reactor. This reactor has a maximum diameter of 7 meters, a length of 22 meters, and a weight of 830 tons; its total cost was 120 million yuan. The first time a large-scale EO reactor was manufactured, every aspect presented challenges: quality control during tube sheet welding and machining, as well as during the deposition of corrosion-resistant layers and drilling; control of the ellipticity of the cylinder sections and the misalignment between them; fabrication and assembly of the grills; quality control of pipe end welding; heat treatment and non-destructive testing; and even lifting operations at the later stages of equipment manufacturing. Focusing on these challenges, Nanhua Machinery identified 12 key tasks across 4 areas, and organized relevant experts to work on solving them. They achieved important innovative results such as the \"turtle-back\" design for tube sheet cladding, the \"plum blossom post\" invention for grid fabrication, the \"steering wheel\" fixture for tube section rounding, and the design of tube end welding processes, paving the way for localization. On September 22, 2011, Yangzi Petrochemical’s large-scale EO reactor was completed. The key technical parameters of the equipment have reached world-class levels, marking the localization of high-end static equipment for large ethylene production, which China has long relied on imports for. This EO reactor, which used domestic materials for the first time, has been operating stably since its commissioning, with no reports of quality issues. Bayerle, a world-renowned supplier of ethylene oxide technology and project manager at an American science and technology design company, said, “Ethylene oxide reactors have complex structures, require special materials, and are difficult to manufacture; numerous tests must be conducted repeatedly. I truly admire Nanhua Machinery’s successful production of its first large-scale reactor.” ” Subsequently, Nanhua Machinery received orders to manufacture two large-scale EO reactors for Sino-Korean Petrochemical, and for the first time produced large-scale EO reactors suitable for the Shell process, thereby expanding its product range. As a major manufacturing base for custom-sized equipment in Sinopec, every EO reactor produced by Nanhua Machinery embodies innovation. The large EO reactor in the Gulei refining and chemical integration project has a maximum diameter of 7.84 meters, making it the equipment with the largest diameter to have been manufactured to date. Nanhua Machinery proposed replacing the manhole with an opening in the last grid, thereby optimizing the reactor structure, which was recognized by the patent holder. Manufactured using the Gulei EO reactor, Nanhua Machinery has also been recognized by patent holders as a global qualified manufacturer. Last March, Nanhua Machinery won a \"rush order\" for the manufacturing of six critical pieces of equipment at the Zhenhai facility, including two large-scale EO reactors; those two EO reactors were delivered to the Zhenhai facility in advance and installed there. In the past, the international procurement cycle for EO reactors was over 3 years. Nanhua Machinery successfully manufactured China’s first large-scale EO reactor, reducing the production cycle to 22 months. The manufacturing of the EO reactor at the Zhenhai facility took only 15 months, at full capacity. The significant scientific and technological achievement of \"Design, Manufacturing, and Maintenance of Critical Pressure Vessels under Extreme Conditions\" has been successfully applied at Sinopec. This not only put an end to China’s long-term reliance on imports for high-end static equipment used in ethylene production at a scale of millions of tons, but it also enables continuous innovation and application, thereby reducing production costs, shortening delivery times, and improving manufacturing quality. According to incomplete statistics, the large-scale EO reactors manufactured by Nanhua Machinery account for over 90% of the domestic demand. These reactors have provided strong support for customer enterprises to steadily improve quality and efficiency. It is reported that in the first nine months of last year, Yangzi Petrochemical’s production of ethylene oxide increased by 70.2% on a year-on-year basis; during the period from April to September, the average daily production exceeded 720 tons for six consecutive months, setting a historical record and enabling maximum efficiency.