Chemical engineering

Valve is an important pressure pipe element with large quantity and wide area in petrochemical equipment, which has the functions of cutting, regulating, diverting, preventing countercurrent, regulating pressure, diverting or overflow, pressure relief, etc. The valve is also the most complex component in the pipeline, which is generally assembled by multiple parts, with complex structure and high technical content.

The application of valves is very wide, in all kinds of petrochemical and chemical equipment, pipeline material costs accounted for about 15% to 20% of the total investment of the project, and the investment cost of valves accounted for about 50% of the total cost of piping, of which the proportion of various types of valves is not the same, taking refining equipment as an example, various types of valves in the device accounted for the total proportion of valves are: Gate valve 80%, globe valve 8%, check valve 6%, these three valves are the most used valves in petrochemical production equipment, other valves account for 6%, and valve investment accounts for 5% to 8% of the device. Taking 2.5 million tons/year atmospheric and vacuum devices and 1.4 million tons/year catalytic cracking devices as examples, the proportion of valve specifications in the total number of valves is: DN≥400 3%, DN150~350 12%, DN50~100 25%, DN≤40 60%.