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In chemical plants, the choice between pneumatic valves and electric valves depends on the specific operational requirements. Each type has its own advantages and suitable applications. The main reasons are as follows: 1. Safety and explosion-proof requirements – Pneumatic valves operate using compressed air, thus eliminating the risk of electrical sparks; they also have excellent explosion-proof properties, making them suitable for environments where flammable and explosive materials are present (such as in petrochemical and chemical manufacturing facilities). Especially in situations where emergency shutdown or frequent operation is required, pneumatic valves offer a fast response time (usually within 1 second) and higher reliability. Electric valves: Although explosion-proof electric valves can also meet safety requirements, motor and circuit failures can generate sparks, and their maintenance costs are high. Therefore, in high-risk areas, pneumatic valves remain the preferred choice. 2. Regulation accuracy and control requirements for electric valves: Intelligent actuators enable high-precision regulation (with an accuracy of up to ±0.1%), making them suitable for applications that require precise control of flow and pressure (such as laboratories and precision reaction vessels). It features flexible control methods, supports remote programming and complex logic, and has better compatibility with PLC/DCS systems. Pneumatic valves: They have a lower regulation accuracy (±0.5%~1%), but positioning devices can meet routine control requirements; they are suitable for applications where high precision is not necessary but rapid response is required (such as the opening and closing control of large pipelines). 3. Installation and dependence on a gas source Pneumatic valves: They rely on a stable gas source; accordingly, air compressors, filtration equipment, etc., must be provided. This results in high initial construction costs, and the laying of gas pipelines is also quite complex. If the factory already has a gas supply system (such as an air compressor station), the long-term operating cost of pneumatic valves is low. Electric valves: Require only a power source, are flexible to install, and are particularly suitable for areas without air supply or in remote locations. For example, in small devices or temporary modification projects, electric valves are more convenient as they do not require a pneumatic power source. 4. Cost and maintenance of pneumatic valves: They have a simple structure, low failure rates, and low maintenance costs (e.g., replacing seals). However, it is necessary to regularly check the air supply pressure and the tightness of the pipes. Electric valves: They have a complex internal structure (motor, reducer, control circuit), require specialized technical skills for maintenance, and involve high initial investment. But in the long run, it may be more economical as there is no need for gas source maintenance. 5. High-pressure, large-diameter systems required for special operating conditions: Pneumatic valves have greater torque, making them suitable for high-pressure, large-diameter pipelines (such as steam control in the power industry). Interference resistance: In strong electromagnetic environments, pneumatic valves are not affected by interference, whereas the control circuits of electric valves may malfunction. Summary: Chemical plants do not rely entirely on pneumatic valves; rather, the choice depends on the specific application. Pneumatic valves are preferred in situations where explosion protection, rapid response, high pressure, or safe shutdown in the event of loss of air pressure is required. Electric valves are suitable for applications that require high-precision control, lack access to air supply, or need complex control logic. The two complement each other, together meeting the diverse process requirements of chemical plants.