工业流化床聚乙烯树脂性能模型的研究

Simulation of Resin Quality in Gas Phase Ethylene Polymerization in Fluidized Bed Reactor

本文首先分析了聚乙烯树脂熔融指数和密度变化的影响因素，建立了流化床动态过程中聚合物性能指标的递推关系和工业流化床乙烯气相聚合过程产品质量的预测模型。利用乙烯气相(共)聚合过程中不同工艺条件下树脂的质量数据，对模型参数进行了优化。提出由于影响因素的相互关联，熔融指数和密度的控制应该联合进行；熔融指数和密度的计算值与测量值之间的平均误差分别为8.19%和0.13%。预测精度满足要求，模型可以应用于具体的工业生产过程。

A model of resin quality and a recurrence formula of the industrial fluidized bed gas-phase polyethylene production process are deduced on the basis of ethylene polymerization kinetics scheme and the flow pattern in fluidized bed. Using a wide variety of experimental data from a commercial process the model parameters have been estimated. It is found that a combined control scheme for MI and density manipulation should be essential due to their strong interaction. A satisfactory agreement was obtained between calculation and experimental data with respect to melt index and density respectively. This model can be used in commercial process with higher relibility.