High-pressure polymerization of ethylene in tubular reactors: A rigorous dynamic model able to predict the full molecular weight distribution

Abstract

A rigorous dynamic model of the high-pressure polymerization of ethylene in tubular reactors is presented. The model is capable of predicting the full molecular weight distribution (MWD), average branching indexes, monomer conversion and average molecular weights as function of time and reactor length. The probability generating function method is applied to model the MWD. This technique allows easy and efficient calculation of the MWD, in spite of the complex mathematical description of the process. The reactor model is used to analyze the dynamic responses of MWD and other process variables under different transition policies, as well as to predict the effects of process perturbations. The influence of the material recycle on the process dynamics is also shown. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.