丙烯腈装置回收塔内聚合物生成原因的分析

针对丙烯腈生产过程中回收塔内聚合物堵塞降液管造成回收塔运行周期短的问题,通过对丙烯腈回收塔内各组分分布的模拟计算,直观显示了回收塔内各组分的浓度分布,发现了回收塔的聚合段与丙烯醛的富集段相吻合的现象,初步得出了回收塔内局部聚合的原因;通过对塔内聚合物的特性分析和评判,进一步证实了“回收塔内局部聚合严重是由于在聚合段丙烯醛聚集引起”这一现象;根据模拟计算结果和实际运行经验,提出了预防聚合物堵塞降液管的措施,并进行了部分生产验证,为丙烯腈生产企业延长装置运行周期提供了理论指导。

Investigation of Polymer formation in Acrylonitrile Recovery Tower

The downcomers in acrylonitrile recovery tower were often blocked up by polymer formed in acrylonitrile production process,which led to short operation cycle of the tower.By simulation calculation of concentration distribution of each component in the tower,it was discovered that acrolein was enriched at polymerization section of recovery tower.The conclusion was further confirmed by means of thermogravimetric analysis(TGA)and FTIR.According to results of simulation and situation of actual operation,improvement measures suggested were improvement of spraying efficiency in quench tower,addition of inhibitor quinol to polymerization section of recovery tower,addition of trapping agent to acrolein enriching zone of recovery tower to make acrolein form chelate and be removed,and addition of initiator to feed stream of recovery tower to make acrolein polymerize before entering the tower and be removed.The above measures could reduce polymer block and had partly been applied in trial production of acrylonitrile.Cycle of plant operation was prolonged.