基于反应机理的乙烯淤浆共聚过程建模

Modeling of ethylene slurry copolymerization system based on reaction mechanism

以工业淤浆法生产高密度聚乙烯的工艺为研究对象,相对分子质量分布和共聚组成为目标,建立共聚流程的稳态模型。采用PC-SAFT状态方程计算聚合体系的物性和相平衡;运用Ziegler-Natta反应机理确定5活性位共聚动力学模型,重新整定了动力学常数。并利用工厂采集的5个串联工艺牌号数据,以相对分子质量分布和共聚组成为质量指标对所建的模型进行了验证,结果表明相对分子质量分布基本吻合,共聚物组成的误差小于5%,为牌号切换的优化奠定了基础。

With the industrial plant of ethylene slurry polymerization as object of study, the molecular mass distribution and copolymer composition as target, the copolymerization process for steady state modeling was studied. The PC-SAFT state equation was used to calculate the copolymerization system property, and the Ziegler-Natta reaction mechanism was used to develop five active sites kinetic model. Using the collected factory designation data in five series grades, the new model was verified to meet the target on relative molecular mass distribution and copolymer composition. The simulation results show that the newly developed model can match well with the analyzed data, while the residual error of molecular mass distribution matches well with the analyzed data, with the error of copolymer composition less than 5%, thus providing the foundation for the optimization of grade transition.