Flow and surge control of the hottest centrifugal

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Centrifugal compressor flow and surge control

introduction the most important thing in the compressor control system is the control of process parameters (i.e. performance parameters), which generally include: 1. Exhaust pressure PD2. Intake pressure PI3. Mass flow qm4. Other relevant variables, such as the temperature of the refrigeration compressor. The operation mode of compressor determines different control schemes of process parameters. The compressor operation modes to be discussed in this paper are: 1 Imported belt 3 well chemical introduced carbon fiber reinforced composites prepared with TPX as matrix; Although there are only a few pieces of heat barrier materials composed of pitch based carbon fibers with graphitized surface, Kureha has constant speed operation of throttling device. 2. Variable speed operation. 3. Constant speed operation with guide vanes at the inlet. The main component of the control of the constant speed compressor with throttling device at the inlet is a pneumatic regulating valve installed in the suction pipeline. For variable-speed compressors, variable-frequency motors or steam turbines can be regarded as control components. The inlet guide vane is the internal throttling device of the compressor, "he said, which can be controlled by the actuator. Surge [4] is a unique phenomenon of centrifugal compressors. Surge control is usually not important during process operation, but it is also important as a compressor protection device, because once surge occurs, the compressor will be in an unsafe working state. In addition, surge control should be set for any system that may reduce the flow below the compressor surge flow in operation. Surge control can be achieved by opening the bypass valve of the compressor or directly venting part of the gas to maintain the minimum flow of the compressor. However, since making the gas pass through the bypass or vent means wasting energy, it is usually hoped to determine the surge flow as accurately as possible, so as to avoid unnecessary waste during actual operation. However, it is not easy to determine the surge flow. Because it is not a fixed value, but related to other parameters, other parameters that also have influence should also be considered in the surge system. Therefore, a variety of control schemes are formed through different measurement methods. Choosing a surge control system suitable for a specific purpose depends on many factors, including: the type of compressor; Load change; The simplicity and reliability of the measuring elements and the accuracy required by the surge control system. Most of the controls commonly used in compressor systems can be applied to surge control. This paper lists several examples of surge regulation. Some of them are designed for the system with constant exhaust pressure, and others are suitable for the change of process parameters. Although these examples cannot include all possible configurations of surge control system, the principles they illustrate will help solve the problems of other special systems. This paper introduces many different types of surge regulation systems derived from various measured values, all of which are based on the theoretical characteristics of the surge line. In many cases, it may be found that the surge line on the compressor drawing provided by the compressor manufacturer is not completely consistent with the theoretical characteristics. One of the reasons is that surge usually occurs in the first stage of multi-stage compressor, but its inlet and exhaust conditions cannot reflect the working conditions of the stage where surge occurs. Nevertheless, taking the surge control system based on the theoretical surge line as the guiding direction, it is still accurate to process parts by exerting strong pressure on the metal blank to make the metal produce plastic deformation and fracture, and it can also be used to test the required protection. In addition, it should be noted that unless the characteristics of the compressor are formulated by unified design, the surge control system should include simple gain and offset adjustment to allow the surge position to be adjusted under the guidance of field experience

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