Evaluation of the Effect of Reaction and Mass Transfer on the Growth of Polymer Particles in Olefin Polymerization

摘要

The process of the growth of polymer particles in olefin polymerization is studied. The regions of the possible overheating of particles due to the polymerization reaction in the gas and liquid phases of a monomer and in a solvent are estimated. It is shown how the rates of external mass transfer, internal diffusion, and reaction in the polymer particle vary with its growth. The cause of unusual transition of the reaction from the diffusion region to the kinetic one with the growth of particles is clearly explained. A model for the dynamics of the polymerization process is proposed that takes into account the diffusion of active component ions of a catalyst (chlorine in Ti_xCl_y, and oxygen in Cr_xO_y). The results of the study are used in the application of high-activity catalysts to the slurry process of propylene polymerization.