Current Status and Development Trends of Chemical Industry Compressors

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I. Introduction to Chemical Compressors Compressors have a wide range of applications and are sometimes referred to as general-purpose machinery. Since the significant development of the petrochemical industry in the 1970s, specialized compressors have been developed to support it, such as compressors for large-scale fertilizer production and the \"three types of machines\" used in the ethylene industry. Specialized chemical compressors also include traditional compressors used in the chemical industry, such as chlorine compressors and compressors for special rare gases. These compressors typically have specific requirements regarding materials, sealing, manufacturing processes, and especially their suitability for handling real gases. Large centrifugal compressors in the fertilizer industry mainly include process air compressors, feed gas compressors, ammonia refrigeration compressors, syngas compressors, and carbon dioxide compressors (commonly referred to as the five major types of compressors). 　 Compressors have a wide range of applications and are sometimes referred to as general-purpose machinery. Since the significant development of the petrochemical industry in the 1970s, specialized compressors have been developed to support it, such as compressors for large-scale fertilizer production and the \"three types of machines\" used in the ethylene industry. Specialized chemical compressors also include traditional compressors used in the chemical industry, such as chlorine compressors and compressors for special rare gases. These compressors typically have specific requirements regarding materials, sealing, manufacturing processes, and especially their suitability for handling real gases. Large centrifugal compressors in the fertilizer industry mainly include process air compressors, feed gas compressors, ammonia refrigeration compressors, syngas compressors, and carbon dioxide compressors (commonly referred to as the five major types of compressors). 　 II. Current Status of Chemical Industry Compressors Since the 1970s, centrifugal compressors in China have seen significant development. During the construction of the 300,000 tons per year domestic synthetic ammonia plant at Shanghai Wujing Chemical Complex, Shanghai Blower Factory, Shanghai Compressor Factory, Shanghai Refrigerator Factory, and Hangzhou Steam Turbine Factory successfully developed process air compressors, syngas compressors, ammonia refrigeration compressors, as well as the corresponding drive steam turbines. During this period, China’s largest specialized manufacturer of centrifugal compressors – Shenyang Blower Factory – and its leading manufacturer of industrial steam turbines – Hangzhou Turbine Factory – introduced advanced technical software and complete sets of equipment from Siemens and Nippon Pump, thereby raising the overall level of design and manufacturing of centrifugal compressor units in China. At the same time, domestic research institutions have also accelerated their research efforts. Universities such as Xi’an Jiaotong University, along with institutions under the Chinese Academy of Sciences, have quickly made breakthroughs in the theory of three-dimensional flow and gas testing. The methods for designing and calculating impellers in three-dimensional flow, as well as the analysis procedures and simulation methods for real gases, have reached international advanced or leading levels. From the late 1970s to the late 1980s, China’s centrifugal compressors saw significant improvements in terms of technical level, process equipment, and quality management. By 1987, when Sichuan Chemical Industry Complex launched a domestic production project for 200,000 tons per year of synthetic ammonia, domestic manufacturers took on the task of manufacturing all the main compressors. At present, all types of centrifugal compressors used in more than 30 large and medium-sized fertilizer plants in our country have been manufactured domestically. According to incomplete statistics, there are over 30 centrifugal compressors for large-scale fertilizers manufactured in China (including through cooperative manufacturing). Compressors used in the ethylene industry mainly include cracking gas compressors, ethylene compressors, and propylene compressors. In the mid-1970s, the chemical industry sector first developed the \"three types of compressors\" required for producing 40,000 tons per year of ethylene (the Jinxī Chemical Machinery Factory developed the ethylene compressor, while the Lanzhou Chemical Machinery Factory developed the compressors for propylene and cracking gas), and these compressors were successfully tested at the Lanzhou plant. Following the 40,000 tons per year ethylene \"three-machine\" unit, Shenyang Blower Factory developed a 120,000 tons per year ethylene \"three-machine\" unit in 1979; the year before that, it supplied a 480,000 tons per year ethylene cracking gas compressor and an propylene compressor to Daqing Petrochemical. Currently, Shenyang Blower Factory has delivered 6 sets of ethylene production units with an annual capacity of 450,000 to 600,000 tons each for use. In fact, our country already has full capability to design and manufacture compression units for various large, medium, and small ethylene plants. 　 III. Development trends of large compressors Large centrifugal compressor units are technology-intensive and highly complex products that require advanced specialized design and manufacturing techniques. As chemical and petrochemical plants continue to grow in size, users are placing increasingly higher demands on technical parameters such as the energy consumption, reliability, and supporting capabilities of compressor systems. 　 Regarding carbon dioxide compressors, there have been some incidents in the past where the performance of the compressors did not match the process conditions. Now, Xi’an Jiaotong University and Shenyang Blower Factory both have their own closed-loop carbon dioxide testing rigs, and the problem has been resolved. Therefore, improvements to large-scale fertilizer and petrochemical compressors have essentially focused on enhancing the compressor’s performance itself. Currently, the world’s leading compressor manufacturers are all engaged in research in this area. The program used in the aerodynamic performance design of compressors can be applied to pressures of several hundred atmospheres, and it is suitable for dozens of complex gases under near-critical conditions, **improving the accuracy of calculations ； In rotor stability research, super-second-order and third-order highly flexible rotors have been developed and successfully applied ； Great progress has also been made in component integration technology, such as in areas like sealing, bearings, control systems, and the level of support equipment. Therefore, it is an urgent task to keep track of the advanced compressor design and manufacturing technologies around the world. To improve large-scale centrifugal compressor units, it is necessary to strengthen research in the following areas. 1. CAD development for 3D engineering design. The use of 3D engineering design can optimize the layout of the units, resulting in an aesthetically pleasing arrangement. It also features an automatic interference check function to prevent design flaws. It can perform structural analysis automatically, improving design accuracy and efficiency. The main development tasks of CAD include creating 3D solid modeling designs, as well as establishing 3D solid device libraries and databases. 　 2. Development of an expert system for the dynamic characteristic design of the rotor-bearing system. During the design process, when the dynamic characteristics of the rotor-bearing system do not meet the requirements of the design specifications, or when the manufactured unit exhibits excessive vibration or unstable operation, it is necessary to modify the structural parameters and material property values of the original unit. However, there are many structural parameters that affect the dynamic characteristics of the rotor-bearing system. The goal of developing this expert system software is to determine which one or several of these structural parameters should be modified in order to achieve the most effective results, thereby promptly resolving issues related to design and the stable operation of the unit. The main research topics include: the influence of various rotor structures and bearing structural parameters on the dynamic characteristics of the rotor-bearing system, and the development of intelligent expert system design and calculation software packages. 　 3. Development of intelligent computer control systems. Currently, the world has widely adopted microcomputer-controlled triple-redundancy, fault-tolerant controllers, as well as multi-functional anti-surge, performance regulation, and safety protection integrated control systems, transforming the control of centrifugal compressors from traditional analog instrument control to multi-functional expert control systems. The main research topics include: developing a digital microcomputer-based integrated control system dedicated to centrifugal compressor units used in large-scale fertilizer plants, featuring anti-surge functionality, performance regulation, and safety protection.