The main applications of valve positioners in petrochemical production

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Valve positioners, classified by structure into pneumatic valve positioners, electro-pneumatic valve positioners, and intelligent valve positioners, are essential accessories for control valves. They are typically used in conjunction with pneumatic control valves; they receive the output signal from the controller and use this signal to control the pneumatic control valve. When the control valve moves, the displacement of the valve stem is fed back to the valve positioner through mechanical mechanisms, and the valve’s position is transmitted to the higher-level system via electrical signals. 　　The digital technology used in field applications for valve positioners creates the conditions necessary for connecting actuators to future field buses. As field buses become increasingly widely used in industrial processes, intelligent valve positioners can communicate with other users of field buses through interfaces. In terms of simple control loops, under certain conditions, it has become possible for intelligent actuators to possess closed-loop process control capabilities. The measuring sensor and the actuator can be connected directly, with operational status and fault information being transmitted to the control room via a field bus. 　　Next, let’s take a look at the main areas in which valve positioners are used in the petrochemical production process. 　　1. Currently, many new or upgraded production units in the petrochemical industry utilize digital systems, DCS, and intelligent transmitters; by using intelligent valve positioners, intelligent control systems can be integrated, thereby enhancing safety and efficiency. 　　2. Used to control petrochemical production processes with very strict requirements, such as equipment for ethylene cracking and catalytic cracking reaction regeneration systems, in order to improve product quality. 　　3. In addition to the petrochemical industry, it can also be used in industrial processes such as those in the oil, chemical, and metallurgical sectors. 4. The production units are currently controlled using conventional instruments; however, to improve the control system, enhance control precision, or counter the effects of significant vibrations in the process pipelines, intelligent valve positioners can be utilized.