英力士高密度聚乙烯装置低压闪蒸釜结块形成原因分析

The analysis of low-pressure flash vessel agglomeration of Innovene S high density polyethylene plant

生产PE100级管材专用树脂的英力士高密度聚乙烯装置杀活停车后,在粉料排空过程中,低压闪蒸罐(V4003)中会逐渐出现较大结块,采用GPC,SEM,DSC等方法对块料和粉料进行了表征。表征结果显示,块料由第Ⅰ反应器(R3001)生产的粉料粒子和低分子量聚乙烯形成。被CO灭活的部分R3001粉料能够在V4003中重新恢复活性,并引发乙烯单体发生原位聚合,且释放的聚合热使低分子量聚乙烯组分熔融,从而彼此黏连形成结块。减少R3001内异丁烷溶解的低分子量聚乙烯组分以及避免粉料在V4003中发生原位聚合是减少停车结块的可行方案。

When Innovene S high density polyethylene plant was shutdown from the production of PE100 pipe resin,big agglomeration would gradually appear in the low-pressure flash tank(V4003)during the emptying process of residual powder in the unit.The agglomerates and powders were further characterized by GPC,SEM,and DSC.The results showed that the agglomerates were formed by powders and low molecular weight polyethylene produced in reactorⅠ(R3001).Part of the R3001 powders which deactivated by CO could be reactivated in V4003 and initiate in-situ polymerization of ethylene monomer.The released heat of polymerization could melt the components of low molecular weight polyethylene which leads to the formation of agglomeration.Reducing the amount of low molecular weight polyethylene dissolved in isobutane of R3001 and avoiding in-situ polymerization of the powders in V4003 are the feasible solutions to reduce the agglomeration during shutdown.