Modeling and Simulation of Olefin Polymerization at Microstructure Level

A new model based on a combination of the polymeric multigrain and multilayer models has been developed to predict the polymerization rate, particle growth, morphology, effective parameters on broadening of the molecular weight distribution, number and weight average of the molecular weight, isotacticity index and bulk density of polymer. Mathematical correlations and the kinetics used in this model are based on the polymeric multigrain and the multilayer models, respectively. In the modeling, multiplicity of active site using different kinetics parameters as well as deactivation of catalyst during the polymerization have been considered,. Moreover, it considers mass transfer effects on polymerization characteristics. The Effects of physico-chemical aspects of catalyst associated with the polymerization in slurry phase are also considered in this model. In addition, the effects of more important model parameters including time step, number of layers and number of active sites on the produced polymer features are reviewed. The model predictions show that propagation rate constant, multiplicity of active site, concentration of any individual active site type, and the initial size of the catalyst particles have considerable effects on the properties of the final polymer. The results obtained from simulation with this new combined model confirm at least better qualitative prediction of the polymerization characteristics in comparison with simulation results of the multigrain model (MGM) and the two models mentioned above.

کلیدواژه ها:

Modeling ، Simulation ، Polyolefin ، polymerization ، Microstructure ، Ziegler-Natta