In chemical production equipment, some media are highly toxic, flammable, explosive and corrosive, and the working conditions are complex and harsh. When the operating temperature and pressure are high, once the valve fails, it will lead to leakage of media. In severe cases, it may even lead to the shutdown of the device and cause a vicious accident.
Therefore, in the coal chemical industry, scientific, reasonable and effective selection of valves can not only reduce the construction cost of the device, but also ensure the safe operation of production. The selection of chemical valves and the matters needing attention are as follows:
Know the use of the valve in the equipment or device to determine the working conditions of the valve, such as the nature of the applicable medium, the working pressure, the working temperature and the control method.
Top entry coal ash slurry control valves
Selecting the right valve
The correct selection of the control valve should be based on the entire production process and operating conditions. When selecting valves, the designer should first grasp the structural characteristics and performance of each valve.
Choosing the connection ends
There are different connection ends such as threaded ends, flange ends and welded ends, among which, the first two kinds are the most commonly used. Threaded valves are mainly flanged valves with nominal diameters, which are easy to install and disassemble. They are expensive and are suitable for pipes with various diameters and pressure. Welded ends are suitable for harsher conditions and are more reliable than flanged connections. However, it is more difficult to disassemble and reinstall valves connected by welding. Valves with welding ends are only used for places with long-term stable operation, harsh and high-temperature environments.
Eccentric rotary coal ash slurry control valves
Selecting chemical valve materials
When selecting the materials of the valve shell, internal parts and sealing surfaces, in addition to considering the physical properties such as temperature and pressure and chemical properties like corrosion of the working medium, we should also take into account the cleanliness of the medium (with or without particles). Moreover, we should know the relevant regulations. Correct and reasonable selection of valve materials can obtain the most economical service life and best performance of the valve. The selection sequence of the valve body material is: cast iron, carbon steel, stainless steel, while the selection sequence of the sealing ring material: rubber, copper, alloy steel, F4.
Also, the flow rate and pressure rating of the fluid flowing through the valve should be determined, and the appropriate valve should be selected using existing information such as catalogs and samples of valves.