Mathematical Modeling of the Catalytic Pyrolysis of High-Density Polyethylene in a Plug-Flow Tubular Reactor

• Published in: Industrial & engineering chemistry research Vol. 58; no. 41; pp. 19050 - 19060
• Main Authors: Zavala-Gutiérrez, Jesús, Pérez-Camacho, Odilia, Villarreal-Cárdenas, Luis, Saldívar-Guerra, Enrique
• Format: Journal Article
• Language: English
• Published: American Chemical Society 16.10.2019
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/acs.iecr.9b04025

A detailed mathematical model for the catalytic pyrolysis of high-density polyethylene is presented. The model is based on the known kinetic mechanism of the catalytic cracking of hydrocarbons, which proceeds via carbenium ions. Mass balances are written for all types of species of each specific length n (n = number of carbon atoms in the chain) that participate in the reaction mechanism: olefins, paraffins, carbenium and carbonium ions, and so forth. The balances are built for a plug-flow tubular reactor operating at the steady state, resulting in a large set of ordinary differential equations (2000–50 000 depending on the starting material in the case of waxes or polymers) with z as a variable (the axial coordinate along the length of the reactor), which are numerically solved. The values for all kinetic parameters are taken from estimates published in the literature. The model predictions are compared with experimental data taken from the literature provided by different research groups.