Please tell me about the polymerization process of 105 kettle
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The day before yesterday, a company came to our place to discuss the polymerization process of 105 kettles. I am not sure about two points. Please give me your advice.: 1. There is an automatic venting process in the early stage of the 105 kettle reaction. It is vented four times, each time for 20 seconds. There is no such thing as a 70-meter kettle. The purpose is said to be to release inert gases. There are 105 kettles used. Is your process the same? 2. The 70 kettle has a medium for filling water, but I heard that the 105 kettle also has a medium for filling the dispersant. What is the reason?
The design ideas of the 105 kettle are different, and the process will be different. The first problem, as far as I know, is because the condenser on the top of the kettle is protected by N2 in the early stage, and there is a nitrogen discharge action during the reaction. ； The second problem has not been encountered yet.
The INERT PURGE of 105 is mainly for heat transfer of RC. If the heat transfer is normal, this operation does not need to be performed. As for adding dispersant midway, you can add any type of dispersant you want. The main thing is to observe the reaction and add dispersant according to the situation.
Our 105 square kettle does have periodic exhaust, and the exhaust is inert gas, because if it is not exhausted, the inert gas will accumulate in the condenser on the top of the kettle, which will cause the condenser to function.* * Reduced. The second question is that we did not inject dispersant midway, but injected water midway.
The secondary injection technology of dispersant can improve the particle morphology of PVC and is beneficial to the production of skinless or skinless resin. However, the ratio and time of primary injection and secondary injection must be grasped. The secondary injection should be before the conversion rate is 10%, and a 70-kettle reactor is also acceptable.
Generally, the inert gas is not vented during the reaction, and it is of little significance to inject dispersant during the polymerization process.
The 105 kettle of our factory has just been opened. It uses an old polymerization kettle from Bei Erhua and does not need to add water to cool it down.
1. The exhaust is to ensure the heat exchange of the condenser on the top of the kettle. How to exhaust the gas specifically for the best effect will be explored based on the production situation.； 2. The secondary injection of dispersant is to improve the quality of the resin. Domestic companies don’t know which company is using it? According to the current domestic PVC market, no one should be willing to adopt this process.
Most processes require water injection midway. Water injection is to make up for the volume change caused by VCM turning into PVC and ensure mass and heat transfer in the reactor.
Reply 1# jxph040443 Japan's technical R/C will exhaust nitrogen. However, it is judged whether to discharge N2 based on the calculation of R/C heat exchange. As for adding dispersant during the reaction process, some domestic factories are using it. I have heard that some companies add a secondary dispersant when making 1000 hard, mainly to adjust the apparent density.