Simulation of a Series of Industrial Slurry Reactors for HDPE Polymerization Process Using Deconvolution of the GPC Graph of Only the First Reactor

Simulation models play a key role in development and operation of polymerization processes. The objective of this work is the simulation of polymerization process of high-density polyethylene (HDPE) in slurry phase using Ziegler-Natta catalyst at industrial scale. Since Ziegler-Natta catalysts produce polyolefins with wide molecular weight and copolymer composition distributions, a multi-site type catalyst model was used for simulating the polymerization process. By deconvoluting the GPC graph of a specimen from the first reactor it was found that at least 5-6 site types should be considered withinthe catalyst for simulating the wide molecular weight distribution of produced polymer. Inour methodology for optimizing the kinetic parameters, the deconvolution of the GPC graph of only the first reactor was used. Six catalyst sites were considered for this purpose and a set of kinetic parameters was proposed for this number of active sites. Results from the simulation showed that the model is able to predict the industrial data e.g., average molecular weight, molecular weight distribution, production rate, and residence time of polymer product. By using the model, the effects of changing hydrogen, monomer, comonomer, and also impurities flow rates were investigated on polymerization rate, mass average molecular weight, and molecular weight distribution.