[Haichuan Chemical Salary News] Nanhua Machinery’s Zhongtian Hechuang water-cooled and air-cooled methanol synthesis reactors have passed the certification process

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News of the world-class methanol synthesis reactor’s completion. Recent reports from Ordos indicate that the water-cooled and air-cooled methanol synthesis reactors, which are key static equipment for the deep processing of coal and were manufactured by the Chemical Machinery Factory of Nanjing Chemical Industry Co., Ltd. (Nanhua Ji), have passed evaluation and have reached a world-class standard. Expert appraisers believe that this large-scale water-cooled and air-cooled methanol synthesis reactor represents a new breakthrough in Chinese manufacturing. Nanhua Machinery provides 2 water-cooled reactors and 1 air-cooled reactor for each of the two methanol synthesis units with a capacity of 1.8 million tons each. The manufacturing of water-cooled and air-cooled methanol synthesis reactors is characterized by high difficulty, high precision, and strict requirements. The domestic production of these 6 water-cooled and air-cooled reactors not only saves investment but also fills the gap in China’s ability to manufacture static equipment for the deep processing of coal independently, thereby further enhancing innovation capabilities. Mastering advanced equipment manufacturing technology: “Our country has abundant coal but limited oil and gas resources; therefore, deep processing of coal is of great importance. The manufacturing technology for the key equipment must, of course, be in our hands.” ”Han Xueyuan, who used to be in charge of operations at the Ordos branch of Nanhua Machinery and is now the deputy secretary of the party committee of the factory, believes that mastering advanced equipment manufacturing technology is crucial for the **economic vitality of a country. For Nanhua Machinery, which is capable of mass-producing reactors in the thousand-ton range, large water-cooled and air-cooled methanol synthesis reactors may not be particularly major pieces of equipment; however, they feature advanced manufacturing processes, complex structures, and high precision requirements, making them key equipment that must be developed for the deep processing of coal. It is reported that the water-cooled and air-cooled methanol reactors manufactured this time have a diameter of 4.2 meters, with an ellipticity of only 3 millimeters, which is less than one-thousandth of the diameter; the manufacturing precision meets all technical requirements, setting a new record. It is reported that at the beginning of equipment manufacturing, patent holders had high requirements regarding the manufacturing process. For example, in the case of water-cooled reactors, the tube sheets and tube boxes had to be welded together first and then placed in a furnace for heat treatment, after which pipe holes were drilled. For the internal components of air-cooled reactors, assembly had to be completed first, followed by separate airtightness tests for those components. To this end, the project team overcame a series of challenges in equipment manufacturing by adopting the internal structure, key details, and special manufacturing processes of the equipment, which were designed by Ningbo Engineering Company and feature patented technology from the German company Lurgi. According to a technician from Nanhua Machinery, they have successfully completed the precision manufacturing of complex curved tube sheets for the first time, and have utilized ordinary forming and machining equipment to process such complex components for the first time as well. These reactors have been operating stably at the Zhongtian Hechuang facility in Ordos, Inner Mongolia, located in the heart of the desert, for over two years now, with all economic and technical indicators meeting the design requirements. The \"golden spiral\" type tube sheet was designed and manufactured. The air-cooled methanol reactor has a diameter of 4.2 meters and a length of 13 meters, yet it is capable of meeting an annual production capacity of 180 tons – a typical example of \"small size, high performance\". The mathematical involute is known as the magical golden spiral. Involute tube sheets enable efficient use of space. In November 2014, stainless steel involute tube sheets were manufactured for the first time in China. The people at Nanhua Machinery spent a full half year working on this tube sheet. Zhou Zhengguo, the director of the reprocessing workshop, has extensive expertise in processing complex curves. First, he used a test piece made of the same material and measuring 500 millimeters on each side for testing: firstly, to verify the procedure and check the accuracy of the programming; secondly, to select the appropriate cutting tool, explore the process parameters, and estimate the time required; thirdly, to detect any cumulative errors. This experiment revealed that cumulative errors occur at the ends of the involute, which leads to an uneven distribution of the tube holes and poses difficulties for subsequent assembly work. Thus, he and the workshop planner Ren Youzhi used VB programming to take 500 points and draw a highly accurate involute curve, laying a quality foundation for the machining of tube sheets, composite baffle plates, and ribbed plates. Welding the involute rib plates on the tube sheet is a challenging task; the rib plates are 240 millimeters high with a gap of only 100 millimeters. During welding, it is necessary to avoid the tube ends, and it is impossible to reach in with the hands or see the weld seam. Gao Shenhua, a senior welder technician at this factory and one of Jiangsu Province’s first master craftsmen, worked together with his colleagues in the riveting and welding workshop to devise solutions. They developed a MIG welding technique for welding involute-shaped casings and tube sheets in tight spaces, designed and manufactured specialized welding fixtures, and modified welding torches. This approach not only resolved this difficult problem but also increased work efficiency by more than three times. Additionally, the plum-blossom baffle of the water-cooled reactor has 4,718 tube holes, with 6 small holes surrounding each one, resembling thousands of blooming plum blossoms. Because the hole spacing is very small, even the slightest carelessness can cause the tube holes to be punctured. Shen Zongwen, a senior mechanic at the factory, led the technicians in designing a positioning fixture for plum blossom-shaped holes, enabling the production of high-precision plum blossom-shaped tube sheets using ordinary drilling machines. This tooling has also obtained a **utility model patent certificate**. Creating a sophisticated “core” with seven openings: It is stated that in water-cooled reactors, holes must be drilled after welding the tube sheet and the tube box; therefore, the drill bit needs to reach inside the tube box in order to access the surface to be processed, but the length of the drill bit is not sufficient. To this end, they further improved the sealing sleeve of the newly manufactured drilling tooling. The diameter of the involute tube sheet in the air-cooled reactor is 4.2 meters, a size that exceeds the machining range of drilling machines; therefore, it is not possible to complete the drilling process in one go. The holes located beyond this range must be shifted before they can be machined. Because after most of the drilling is completed, the tube sheet acts like a huge, soft sieve and is extremely prone to deformation. Subsequently, Zhou Zhengguo designed a tube sheet fixing fixture; when moving it, it is sufficient to lift the fixture, which not only prevents deformation of the tube sheet but also facilitates alignment. The airtightness test of the tube bundle in the air-cooled methanol reactor has given Wang Minglong, the deputy director of Workshop 3, a real headache. He designed and built a temporary \"housing\" to enclose the internal components; he also made many rectangular pads to seal all the pipe openings. However, the thermocouples installed on the tube sheet and the oblong holes (slit-shaped holes) at the sampling points posed a problem, as the portion of the thermocouples that extended beyond the tube sheet acted like a \"hilt,\" interfering with normal operation. Wang Minglong believes that if the structure of the thermocouple sleeve can be modified, it will be possible to insert the \"sword handle\" into the container, conduct a airtightness test, and then pull it out. He also designed an inner part pulling tool that allowed the inner part to \"slide\" into the housing, with a gap of only 20 millimeters. In this way, this highly sophisticated “core” that embodies the innovative wisdom and craftsmanship of the people at Nanhua Machinery has become another major masterpiece of Chinese manufacturing in the field of coal deep processing.