A Single Particle Model to Predict the Impact of Induced Condensing Agents on Polymerizing Particles During the Gas Phase Polymerization of Ethylene

Abstract

AbstractA single particle model for homopolymerization of ethylene in the presence of hydrogen is used to predict the impact of induced condensing agents on the evolution of concentration profiles in the growing particle, the rate of homopolymerization, and the evolution of the molecular weight distribution. The model formulation is based on the random‐pore polymer flow model associated with a kinetic model using the method of moments to describe the chain length. The Sanchez–Lacombe equation of state is applied to calculate the equilibrium concentration of each penetrant in a mixture of gases in the amorphous polymer phase. The free volume model from Vrentas and Duda is employed to calculate the diffusivity coefficients of penetrants in a semi‐crystalline polymer. The model confirms that the increased rates of production and increased molecular weights observed in previously published experimental studies are due in large part to the co‐solubility and co‐diffusivity effects.