LDPE Production in Tubular Reactors: Comprehensive Model for the Prediction of the Joint Molecular Weight-Short (Long) Chain Branching Distributions

• Published in: Industrial & engineering chemistry research Vol. 58; no. 11; pp. 4412 - 4424
• Main Authors: Dietrich, Maira L, Sarmoria, Claudia, Brandolin, Adriana, Asteasuain, Mariano
• Format: Journal Article
• Language: English
• Published: American Chemical Society 20.03.2019
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/acs.iecr.8b05713

Good control on molecular properties, and as a consequence on end-use properties, is very important for low-density polyethylene (LDPE) manufacturers. However, the connection between the architecture of polymer chains and the kinetic mechanism and polymerization conditions is still a subject of study. In this work, we present a comprehensive model of the polymerization of ethylene in high-pressure tubular reactors. In addition to the usual predictions of conversion, temperature profiles, and average molecular properties, this model also provides bivariate distributions such as molecular-weight–long-chain branching distribution and molecular-weight–short-chain branching distribution of LDPE produced under different operating conditions. The 2D probability-generating function technique is applied to obtain the bivariate distributions. This is a deterministic technique that allows the calculation of the distributions without any prior assumption of their shape.