Impact of Internal Particle Morphology during Gas-Phase Ethylene Polymerization: A New Particle Model Approach

A single-particle model for mass transfer in heterogeneously catalyzed olefin polymerization is presented. By constructing the growing particle as an assembly of different-sized mesoparticles, the model allows us to explore the impact of different internal particle morphologies on the mass transfer process. As one might expect, mass transfer limitations become more pronounced as the rate of polymerization increases. Simulations show that mass transfer limitations become more pronounced as the size of the mesoparticles increases; larger mesoparticles also grow more slowly than smaller ones. In addition, larger mesoparticles grow slightly less than smaller ones, with this difference becoming more pronounced as the intrinsic polymerization rate increases. Finally, in a reactor cascade process, the intermediate degassing step can affect polymer properties for certain internal particle morphologies.