低等规聚丙烯的研制 Ⅴ.粘性聚合物的分离技术

Study on low isotactic polypropyleneⅤ. Separation technique for viscous polymer

采用液相本体法生产的粘性低等规聚丙烯在排放输送和分离回收时易堵塞阀门和管道。模试结果表明:控制聚合时丙烯转化率为20％～50％.同时预先在闪蒸釜中加入表面分散剂质量分数约0.3％的液体介质及预先充入丙烯单体可以有效地解决这一问题。介绍了采用乙醇-水溶液作为分散介质的分离技术特征,并可用深度冷冻法或吸附极性分子法从回收体系中除去乙醇。

Valve and pipeline was easily jammed or blockaded by the viscous low isotactic polypropylene produced in a process of liquid phase bulk polymerization during the stages of discharge, transportation, separation and recovery. The result of model experiment show that this problem can be effectively solved by a method in which the propylene conversion is controlled at 20% - 50%, a kind of liquid media containing surfactant of about 0.3% (mass fraction) as well as propylene monomers are added into the flashing kettle in advance. Characters of the separation technique are described, which takes alcohol-water system as dispersion medium. The alcohol in recovery system can be removed by either deep-freezing method or absorption method of polar molecule.