Selection requirements for the acetylene control valve before the mixer in the calcium carbide process for vinyl chloride synthesis
Thread Content
The acetylene control valve before the mixer in the calcium carbide process for vinyl chloride synthesis is primarily used to adjust the mixture ratio and to enable rapid shutdown in emergency situations. Are there any more specific requirements regarding the selection of this valve?
Due to its large pore size, a pneumatic butterfly valve is generally used for this acetylene control valve. Whether an anti-corrosion version should be employed depends on the specific characteristics of the enterprise – in other words, whether this control valve will be exposed to HCL gas. If exposure can be avoided, then a carbon steel valve will suffice. Otherwise, an anti-corrosion type must be selected.
If the process requires rapid cutting off, a solenoid valve should be added.
We have chosen butterfly valves. Electric.
The material for high-performance butterfly valves can be determined based on the properties of acetylene gas; the key is to ensure that the flow velocity does not exceed 6 m/s
Why choose a control valve? Just choose a shut-off valve; its purpose is to provide emergency shutdown, not for regulation. The shut-off valve can be of butterfly or ball type to reduce operating resistance and enable rapid shutdown; it can be driven electrically or pneumatically.
It is difficult to achieve leak-free operation for control valves; if both regulation and shutdown are required, it is recommended to use a dual-valve system (control valve + shut-off valve)
Selection of acetylene valves: Due to the special characteristics of the process in this area, it is required that the acetylene control valve have both regulating and rapid shut-off functions. With a plant capacity of 200,000 tons per year of VCM, the diameter of the acetylene control valve should be around 500–600 mm; therefore, a regular control valve cannot be used, and instead, a wafer-type pneumatic control butterfly valve is suitable.
This post was last edited by Lin Xuefeng on 2009-10-22 at 19:30. It is estimated that in many enterprises, the acetylene automatic control valves are used for shut-off purposes; the adjustment function is hardly ever utilized, as there is no need for adjustment at this stage from a process perspective. Instead, valves with adjustment capabilities are placed in the acetylene processing unit, with control being implemented in the synthesis unit. Therefore, many companies here choose pneumatic or electric butterfly valves; since manual valves are also available, corrosion protection is generally not considered for these valves.