3. Application of defoamer in discharging
After the polymerization, the slurry after the reaction is discharged to the discharge tank, and the unreacted VCM is discharged. When draining the unreacted gas, there will be a lot of bubbles in the discharge tank. These bubbles are discharged with unreacted gases, which often cause many problems such as pipe blockage, material waste and so on. Defoamer can eliminate these bubbles. The defoamer used in this process is generally added by the manufacturer at the same time as the terminating agent. The selected defoamer should have a wide range of pH value application, good defoaming performance and the best defoaming performance, because for most small and medium-sized enterprises, the recovery of VCM monomer does not use stripper recovery, and no defoamer is added in the process of VCM monomer recovery, but the recovery process needs a considerable period of time, so the defoamer defoaming performance directly affects the recovery of VC. M speed and time of monomer. Defoamer is used in this production stage. It has good defoaming performance and anti foaming performance, and can effectively eliminate and inhibit foam production in the whole recovery process.

4. Application of defoamer in stripper operation
For the enterprises using stripper for VCM monomer recovery, when the reaction is finished, the slurry VCM is removed by stripping. As they are generally carried out in the stripper, the slurry flows from the top of the tower to the bottom of the tower, and the steam is fully heated with the slurry from the bottom of the tower to the slurry. During this process, the slurry on each tray will generate foam. These foams will seriously impede the volatilization of VCM, increase the power of removing VCM, and keep the foam on the tower wall for a long time, and produce "black and yellow particles", which will affect the quality of products. In order to eliminate foam production during stripping operation. Defoamer is required. The defoamer should be diluted properly and added to the stripping equipment evenly, because the addition of high concentration defoamer may cause excessive adsorption of PVC particles and affect the recovery and post-treatment of VCM monomer. Therefore, the defoamer is used for dilution and then added continuously. It can eliminate a large number of bubbles generated during stripping, increase recovery speed and speed up the recovery process.