The development history of centrifugal compressors in our country

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China’s centrifugal compressors have gone through two major phases of development, both of which are closely related to modern industrial production. Once was in the 1970s and 1980s, when our country imported large-scale petrochemical plants from abroad. In one major instance, more than 20 production units for fiber optics, ethylene, vinyl chloride, large-scale fertilizers, alkylbenzene, and other products were imported, at a total cost of 13.7 billion yuan (while the annual investment in capital construction at that time was around 40 billion yuan). At the same time, to ensure the operation of the imported equipment and the supply of spare parts, centrifugal compressors of world-class standard along with their corresponding drive units were specifically introduced. This move greatly promoted the development of centrifugal compressor units, resulting in a range of specialized compressors designed to work in close harmony with the relevant processes. Its representative units are the “five major units” in large fertilizer plants and the “three units” in ethylene plants. In fact, there are many products in the petrochemical industry, which means there are also a wide variety of compressors. It has been over a decade since the second half of 2002, and centrifugal compressors have once again experienced a period of rapid and steady growth, with an average annual growth rate of over 25%. This development is different from the previous sudden introduction, and is related to the pace of advancement of China’s heavy industry. According to economists, China’s industrialization is still in an upward phase; at least until 2020, the trend toward a more industrialized and heavy-industry-oriented economy in China is inevitable. Therefore, the industry of raw materials and raw goods is still in a period of rapid growth, and pump products, as key equipment, will maintain long-term demand. However, due to various international and domestic factors, its development speed cannot be as fast as in previous years. If the development pace slightly higher than that of the 1990s is maintained (with an average growth rate of 10%–12% in the 1990s), the average growth rate is expected to reach around 15%. Industry Status and Market Demand: After more than 40 years of development, China’s centrifugal compressor industry has entered a period of rapid and stable growth. The general situation of this industry is as follows: 1. Centrifugal compressors have become key equipment in chemical processing units that use petrochemical fuels (coal, natural gas, oil), playing an irreplaceable role in the efficient utilization of heat and cost reduction. The fact that China’s energy structure is dominated by petrochemical fuels is unlikely to change significantly in the near future; therefore, there will continue to be a strong demand for centrifugal compressors for a considerable period of time. On December 13, 2011, the “12th Five-Year Development Plan for the Petrochemical and Chemical Industries” was released. Along with it, four sub-plans were issued regarding olefins, hazardous chemicals, pesticides, and fertilizers. It is evident from the Plan that during the 12th Five-Year Period, China’s petrochemical and chemical industries will undergo a transformation from being large in scale to becoming strong in competitiveness. According to information on industry development, sectors such as oil refining, ethylene production, synthetic materials, oil and gas transportation and liquefaction, as well as coal chemical processing have all seen significant growth. In the field of coal chemical processing alone, 104 projects are set to be launched within 5 years, with a total investment amounting to possibly 1.5 trillion yuan. Based on past statistics, the average annual demand for centrifugal compressors is significantly higher than the average growth rate of GDP (about 1.5 times higher). It is estimated that by 2015, the average annual demand for centrifugal compressors in China will reach around 20 billion yuan. Table 2 shows the production volume of domestic large-scale turbine compressors in recent years. 2. The localization of centrifugal compressors has seen significant improvement. In large petrochemical plants that are under construction or undergoing expansion and renovation, the domestic production rate of centrifugal compressors can reach 85% to 90% or more. China’s major centrifugal compressor manufacturers, such as SHENGU Group and SHANGU Group, are not inferior to internationally renowned companies in terms of design technology, computational methods, advanced manufacturing equipment, and processing capabilities. Since 2000, the rapid economic growth and high demand in China have attracted many renowned international manufacturers to enter the market. Today, almost all of the top 20 companies in the world have subsidiaries, agents, or joint ventures in China; as a result, China’s centrifugal compressor market has become a world-class market, with its technical standards reaching international levels. 3. China’s centrifugal compressor manufacturing industry is relatively concentrated in three major areas: the old industrial base in the Northeast, the Yangtze River Delta economic development zone, and the western region. In the old industrial bases in the northeast, led by Shenyu Pump, there are also Jinxī Chemical Machinery and Simens’ factory in Huludao – these places serve as the main production sites for chemical centrifugal compressors in China at present. Shenmu is the leading company among the “five major manufacturers” in the fan industry. It is a major producer of centrifugal compressors in China, and it is also an enterprise in this sector with annual revenue exceeding 10 billion yuan. In the Yangtze River Delta Economic Development Zone, there are large state-owned enterprises such as Shanggu and Hangyang, as well as a significant number of foreign-funded companies, including Atlas Copco (Wuxi), Ingersoll-Rand (Shanghai), Samsung TurboMaster (Wuxi, Shanghai), ManTurbo (Changzhou), Fs-Elliott (Shanghai), Cameron-Cooper (Quanzhou), KobelCo (Wuxi), IHI-Sullair (Suzhou), and others. In addition, there are also some emerging domestic enterprises. This region has concentrated resources, complete industrial infrastructure, strong capabilities for collaborative procurement, dynamic enterprises, and high competitiveness. Western region enterprises such as Shaanxi Blower, Jiaotong Saier, and Chongqing General Machinery each have their own distinct characteristics. Shanxi Gear Group is a company that specializes in the production of axial flow compressors, centrifugal compressors, and industrial process energy recovery units, and it boasts a completely new approach to service delivery ； Jiaodaixiel is a technology-based enterprise that integrates testing, selection, design, manufacturing, engineering, and services, and was developed based on the \"fully controllable vortex\" three-dimensional flow theory independently created by Xi’an Jiaotong University ； Chongqing General focuses on the production of complete sets of centrifugal refrigeration compressors. With the development of oil and gas resources in the western region, as well as the growth of the coal chemical industry in Xinjiang and Inner Mongolia, the turbine compressor manufacturing industry in this region enjoys distinct geographical advantages. 4. Overall, there is still a certain gap between China’s centrifugal compressor manufacturing industry and that of foreign countries, with the main differences lying in investment in research and development and product quality. Based on certain aspects of product manufacturing and supply, the differences between domestic and international compressor products are outlined below. What drives the development of centrifugal compressors is market demand, namely various explicit and implicit needs of users. In summary, there are mainly the following aspects: 1. Improving the quality and reliability of equipment. Centrifugal compressors also have a variety of quality shortcomings; even those made abroad have encountered more or less problems during use. Overall, their performance is described as being ‘generally good’ or ‘basically meeting production requirements’, and they are still some way off being considered ‘high-quality’ or ‘reliable’ products. For domestic products, the gap is even greater. Users support localization, but hope to further improve quality and enhance the credibility of the products. 2. Improve service quality and desire personalized services. For users, high-quality after-sales service and timely supply of spare parts are essential; they expect the supplier to be able to arrive at the site quickly to address any issues that arise during equipment operation. Users have reported that the after-sales service provided by foreign companies is poor, and spare parts are difficult to obtain at high prices ； Domestic manufacturers tend to focus on the main units while giving less attention to auxiliary units; if a problem occurs with the main unit, repairs can be carried out promptly ； However, if there are problems with the auxiliary systems, such as faults in the lubrication system or cooling system, they are often not dealt with properly. Secondly, users may also have various requirements during the production process, hoping that manufacturers will change their service philosophy to deliver services that meet these specific needs. Users don’t just purchase a product; they seek personalized services that help them meet their various needs related to compressors. 3. Shorten delivery times and call for an era of prefabrication. The normal delivery time for centrifugal compressors is generally around 20 to 25 months. Due to the long investment cycle for the construction party, they hope to shorten the construction period as much as possible. In a buyer’s market, equipment suppliers are often forced to compress the design and manufacturing cycles into an abnormally short period in order to secure orders; as a result, there are either delays in delivery or defects in the quality of the equipment. Therefore, the market calls for a process of prefabricating certain components under single-unit development conditions (covering the entire process of design, calculation, manufacturing, and testing) – that is, the advent of an era of prefabricated centrifugal compressors. The prefabrication requirements for centrifugal compressors demand that design calculations be modeled, components be standardized and generalized, modularization be achieved, and the assembly of the complete unit follow a more mature, reliable, rigorous, and scientific approach. 4. Other requirements for centrifugal compressors. The requirements for centrifugal compressors are diverse; for example, when it comes to complete equipment packages, users generally expect the manufacturer to include the drive unit in the supply. Normally, the motor is included in the scope of supply, but the turbine is provided by another manufacturer; its oil system, control system, foundation, pipelines, etc. form their own separate systems. Therefore, improving the capability to supply complete sets of equipment requires collaborative efforts from various parties. Similarly, giving equal emphasis to technology and equipment is also a consistent goal of users. In chemical production, due to the particularities such as temperature (high or low), sealing issues (toxic substances, leakage risks, flammability, explosiveness), process characteristics (corrosion, erosion, coking), the production environment, and environmental regulations, it is necessary that equipment performance meets the requirements of the process. Manufacturers must therefore have a thorough understanding of these process characteristics in order to design units with reasonable structures whose performance can satisfy the production needs; this represents a goal that manufacturers must strive to achieve over the long term. Market demand drives technological innovation. Turbocompressors are currently evolving toward larger sizes, higher efficiency and energy savings, customization (specialized compressors tailored to specific process requirements), as well as improved overall performance (stability, reliability, and environmental friendliness). A new product often incorporates many new technologies; the following introduces several high-tech products. 1. Electric drive compressors refer to units in which a centrifugal compressor is driven directly by an inverter-driven motor, without the need for gear transmission; as a result, they offer advantages such as small size, simple maintenance, high efficiency, and no pollution. It is reported that the maintenance costs for motors are only one-fourth of those for steam turbines or gas turbines. Noise levels can be reduced by more than 20 decibels, and emissions such as CO, NO, SO, wastewater, and used oil are minimized, meeting modern environmental standards. Currently, they are mainly used in natural gas transportation and similar applications. Figure 2 shows an “integrated electric-driven compressor” developed by GE. The motor and compressor are housed in a bolted cylindrical casing, and the main unit can accommodate multiple impellers. One of the key technologies is the use of magnetic bearings, which eliminates the need for a lubrication system. Additionally, since the process gas flows internally within a sealed cylindrical casing, it does not leak to the outside; therefore, no sealing system is required. At the same time, this process gas can also serve as a coolant to cool the motor, eliminating the need for external cooling. Magnetic bearings are divided into radial magnetic bearings and axial magnetic bearings; they rely on magnetic force to suspend the rotating shaft for high-speed rotation or to provide thrust. In this way, replacing oil film friction with gas friction reduces friction losses. Domestically produced 20MW-class electric drive compressor units have achieved self-sufficiency in production. The first batch of such units, developed as part of key research projects carried out by Shenyang Blower Group, Shanghai Electric Group, and Guangdian Electric, have been used in the West-East Gas Pipeline Project II. The unit consists of a pipeline compressor, a high-speed explosion-proof synchronous motor, a high-pressure variable-frequency speed control device, a comprehensive unit control system, auxiliary systems, and integrated joint debugging tests. The rated speed of the motor is 4800 rpm; the capacity of the frequency converter is 25 MVA. The compressor’s speed reaches 4740 rpm. 2. High-flow and high-pressure turbine compressors: The pressure and flow range of centrifugal compressors is continuously expanding. At last year’s Fifth Shanghai International Compressor and Fan Summit, MAN Diesel & Turbo presented a radial-axial MAX1 type compressor developed for large-scale air separation units. Seven stages of axial blades together with two stages of centrifugal impellers are mounted on the same shaft (with inter-stage coolers in between); the outlet pressure ranges from 0.8 to 0.9 MPa, and the gas flow rate can reach 700,000 to 1.5 million m3/h. Depending on the required gas flow rate and pressure, the number of stages in the axial and centrifugal sections can be increased or decreased. For example, the MAX1 air compressor, which can produce 5,512 tons of oxygen per hour (with an oxygen flow rate of around 160,000 m3/h), features 10 axial stages and 3 radial stages, allowing for a compression ratio of up to 21. These compressors are characterized by a large flow rate and a high pressure ratio. Their structural design can be adjusted according to process requirements, offering good adaptability to various operating conditions, high reliability, and easy maintenance. In addition to air separation, it is also used in downstream processing units for the steel, fertilizer, oil, and gas industries. In addition to high-flow and high-pressure compressors, Man Turpin has also developed an ultra-high-pressure centrifugal compressor. This canister-type compressor boasts a maximum suction flow rate of 230,000 m³/h, with a maximum pressure of up to 100,000 kPa. It is primarily used in the upstream, midstream, and downstream sectors of the oil and natural gas industries. 3. Applications of centrifugal compressors in natural gas storage and transportation projects
The application of centrifugal compressors in natural gas storage and transportation projects is one of the important applications in recent years. It represents another milestone development, following the widespread use of centrifugal compressors in petrochemical plants during the 1970s. Its characteristics are: First, it has a wide range of applications and a large market. As a highly efficient, high-quality, clean energy source and a raw material for petrochemical industries, natural gas is finding increasingly diverse applications, with its demand continuing to rise. The pipeline transportation, liquefaction, storage, and transportation of natural gas represent a long-term and essential requirement. Second, it is technically complex and requires high standards. Since pipeline compressors must operate in harsh and complex outdoor environments (resistant to earthquakes, wind, sand, lightning, corrosion, and suitable for flammable and explosive conditions), they are required to operate reliably over long periods, while also possessing a wide regulation range, good adaptability, and high operational efficiency. Therefore, the development of pipeline compressors involves multiple disciplines and priority areas; it is a highly integrated systems engineering project that features advanced technology, complex systems, and spans various disciplines and specialties. For natural gas liquefaction, refrigeration compressors are used, with key technologies including low-temperature materials (alloy steel) and high-Mach-number stage designs. A single electric-driven compressor unit for pipeline gas transmission; in the diagram, the compressor uses lubricated bearings, while the sealing is achieved through a dry gas seal system. Summary: Although the growth rate of centrifugal compressors has been declining since last year, their energy-saving and low-consumption operational characteristics, along with their inherent compatibility with industrial production processes, will ensure their continued rapid development. The market resources in our country are not being fully utilized; the huge domestic market creates extremely favorable conditions for the use of centrifugal compressors. Regardless of the nature of the enterprise (state-owned, private, or foreign-funded), it must possess the capabilities and mindset for innovation (the ability to develop new technologies), a strong brand image (quality and integrity), and excellent service (improving service standards) in order to compete successfully in the fierce market of China.