Compressor Technology Status and Development Trend
In the field of petrochemicals, currently domestic centrifugal compressors cannot meet domestic needs in terms of high technology and special products. In addition, there is still a gap with foreign countries in terms of technical level, quality, and completeness. As China's petrochemical production scale continues to expand, centrifugal compressors will face new challenges in terms of large-scale development. There is no mature experience in the design and manufacture of these large-scale gas compressors. Centrifugal compressors need to be developed to large capacity to meet the requirements of the continuous expansion of China's petrochemical production scale. At the same time, with the development of new technologies, new types of gas seals, magnetic bearings and non-lubrication couplings, the development of turbocompressors The trend is mainly manifested as: continuous development of high pressure and low flow products; further study of the ternary flow theory, applying it to the design of components such as impellers and vane diffusers, in order to achieve efficient units; low noise, using noise protection to improve Operating environment.
In the field of refrigeration and air conditioning, current turbo compressors still maintain their advantages within a large range of refrigeration. Centrifugal compressors have few moving parts and are simple and have low manufacturing precision, so their manufacturing costs are relatively low and their reliability is high. Due to the influence of screw compressors and absorption chillers, the development of centrifugal refrigeration compressors is relatively slow. Under the current technical conditions, centrifugal refrigeration compressors are mainly used for air conditioning in large buildings with less demand. In recent years, large-scale infrastructure projects have been launched. Centrifugal refrigeration compressors have become a hot issue.
2. Reciprocating compressor
In the field of petrochemicals, reciprocating compressors are mainly oriented toward large capacity, high pressure, low noise, high efficiency, and high reliability. They are constantly developing new types of valves that operate under variable operating conditions to increase valve life. In terms of design, thermodynamics and dynamics theory are applied to predict the performance of the compressor under actual operating conditions through comprehensive simulation; the electromechanical integration of the compressor is intensified, and computerized automatic control is used to optimize energy-saving operation and online operation.
In the field of power, piston compressors currently occupy a major market. However, with the increase in requirements for the use of the environment, energy consumption, and environmental protection, screw and scroll air compressors have begun to occupy a certain market.
In the field of refrigeration and air conditioning, reciprocating refrigeration compressors, as a traditional refrigeration compressor, are suitable for refrigeration systems with a wide range of cooling capacities. Although its application is still relatively extensive, its market share is gradually decreasing.
At present, mainframes of refrigerators (including small freezers and refrigerators) refrigeration systems are still mainly reciprocating compressors. After years of design improvements and technological advancements, the efficiency of reciprocating refrigerator compressors has greatly increased. At the same time, gratifying progress has also been made in refrigerant replacement technologies closely related to environmental protection. Further improving the efficiency of reciprocating refrigerator compressors and reducing system noise is its main development direction.
(1) Linear (Linear) Compressor The linear compressor is a type of reciprocating compressor. Since the linear motion of the motor can directly drive the reciprocating motion of the piston, it avoids the complexity of the crank linkage mechanism and the resulting The mechanical power consumption. The key technology of the linear compressor is the design of the compressor oil system, the effective control of the linear displacement limit point of the motor, and the corresponding anti-collision technology.
(2) Swashplate Compressors Swashplate compressors are also a variant of reciprocating compressors and are mainly used in automotive air conditioning systems. After decades of development, swash plate type compressors have become a very mature model, accounting for more than 70% of the market share of automotive air conditioner compressors. However, its efficiency is lower than that of rotary compressors, and its volume is large. Due to the mature technology of swashplate air conditioning compressors and the further improvement of technology, it will still maintain a certain market share in the foreseeable future, but it is inevitable that it will gradually be replaced within a certain range of displacement.
3. Rotary compressor
(1) Rolling Rotor Compressors Rolling Rotor Compressors are currently widely used in household air conditioners and have certain applications in refrigerators. This type of compressor does not require a suction valve, making it suitable for variable speed operation, which can improve system performance through variable frequency control. In order to ensure the performance of the high-power (motor output power 2.2kW (3P)) rolling-rotor compressor, domestically developed dual-rotor rolling-rotor compressors at the end of the last century have now been put on the market.
In a 2.2kW (3P) or less air conditioner, there is no better alternative to a rolling rotor compressor. Therefore, to improve the efficiency of the compression process, reduce noise, motor speed control, and the use of new refrigeration refrigerants such as R410A related technical issues, etc., is the research direction of the rolling rotor compressor.
(2) The vane compressor The vane compressor is a kind of rotary compressor and is mainly used to supply compressed air. The displacement is generally 0.3 to 3 m 3 /min and the market share is low. The rotary vane compressor is a modified structure of the vane compressor. Due to its good starting performance and little change in the torque during the compression process, it is mainly used in miniature cars and some small displacement car tools. Air Conditioning System. The dynamic characteristics at high speeds are the main technical research directions of this compressor.
(3) Scroll Compressors Scroll compressors have developed rapidly in the past ten years and constitute a new bright spot for compressor technology development. At present, scroll compressors have an absolute advantage in the field of cabinet air conditioners. In the field of automotive air conditioning, the scroll compressor's coefficient of performance has reached 2.0, showing strong competitiveness. The development of scroll compressors is to expand the scope of their refrigeration capacity, further improve efficiency, use alternative refrigerants and reduce manufacturing costs.
(4) Screw Compressors Screw compressors have the characteristics of small size, light weight, easy maintenance, etc., and are a kind of rapid development in refrigeration compressors. On the one hand, there has been considerable progress in the design of screw profiles and structures. On the other hand, the introduction of the screw rotor special milling machine, especially the grinding machine, has improved the processing accuracy and processing efficiency of these key parts, and the performance of the screw compressor has been effectively improved. At present, screw compressors are mainly used in compressed air and medium-sized refrigeration heat pump air conditioning systems. Due to the continuous improvement of the reliability of the screw compressor, it has gradually replaced the reciprocating compressor in the medium refrigeration range, and has occupied a part of the centrifugal compressor market.