Multi-component mass transfer in a single particle during gaseous propylene polymerization

Abstract

Mass transfer in the growing catalyst/polymer particle is modeled with dusty gas model (DGM), while the particle growth is described with Polymeric Flow. A Thiele modulus defined in terms of diffusion combined with viscous flow, is called viscous modulus, and used to analyze the dominating mechanism for mass transfer when there is an additional transport of reactant (convection) along with diffusion in a single reacting particle. Addition of high or low molecular weight inert/diluent gas affects mixture diffusivity and thus decreases or increases reaction rate respectively. Both propylene-N₂ and propylene-C₃H₈ systems, which are commonly employed in industry, are studied. Effect of low molecular weight inert is studied with propylene-He system. Porosity and pore size effect on reaction rate is also discussed.