Spheripol工艺丙烯聚合质量模型

Mathematical Modeling of Polypropylene Quality for Spheripol Process

针对Spheripol工艺,根据Z-N催化剂聚合机理,对不同牌号聚丙烯产品(包括均聚聚丙烯、无规共聚聚丙烯和抗冲聚丙烯)分别建立了熔融指数和乙烯质量分率的预测模型。并应用实际生产数据,对模型进行优化拟合,得到了模型参数。结果表明,熔融指数和乙烯质量分率预测模型的计算值与分析值之间的平均相对误差分别为3.86%和13.5%,模型可以较为准确地预测树脂质量,对聚合产品质量的软测量及牌号切换的研究有很大帮助。

The prediction of the melt index and ethylene content for polypropylene （PP） was investigated, and both of them are the key quality index of PP production. Aimed at the Spheripol technology and based on the polymerization kinetic mechanism of Ziegler-Natta （Z-N） catalyst, the mathematical models of melt index and ethylene content were established respectively for the predictions of melt index and ethylene content of the polypropylene products with different grades including the homo-PP, random copolymer of propylene-ethylene and impact poly（ethylene-propylene）. The dynamic production data from an industry plant were used for the fitting of the models proposed, and from which the parameters of the models were obtained. The results show that using the models proposed, the average relative errors between the model prediction and the practical analysis are 3.86% for melt index and 13.5% for ethylene content, respectively, which indicates that the models proposed can be used in industrial plants to predict the quality of the PP products accurately and can be a great help to the soft-sensor design and the optimization of grade transition.