Reason for polymer in the overhead of the pure styrene column
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Why is there polymer in the top of the pure styrene column? Increasing the reflux does not help
Is the temperature at the bottom of the tower too high?
The temperature probably wasn’t controlled properly. It seems that styrene is the second easiest to polymerize……
Regardless of the temperature control, materials such as styrene tend to polymerize easily. By adding some polymerization inhibitors and injecting them into the top of the tower using a plunger pump – in amounts of a few liters or more – polymerization can be reduced.
It is normal for there to be aggregates at the top of the purified styrene column, but the amount present depends on the properties of the styrene material; such aggregates are inevitable during the distillation process. If the amount of polymer present exceeds 10PPM, it is necessary to investigate the cause. Recommendations include: 1. Analyzing the temperature variations between the packing layers in the purified styrene column; 2. Analyzing changes in the amount of tar at the bottom of the column as well as the styrene content in that tar. Possible causes include: 1. Intentionally reducing the amount of tar or the styrene content in the tar can lead to polymers being carried from the bottom of the column to the top; 2. An abnormal amount of antipolymerizing agent being used; 3. An insufficient load on the plant, or a too high reflux ratio, which can result in styrene staying in the column for too long and thus increase the amount of polymers.