Molecular-Level Kinetic Modeling of Resid Pyrolysis

Abstract

A molecular-level kinetic model of heavy oil pyrolysis was developed for a Venezuelan vacuum residue. Model development proceeded in three major steps: creation of a molecular description of the feedstock, generation of a reaction network, and model solution and parameter tuning. The feedstock composition, as described in previous work [Zhang et al. Energy Fuels 2014, 28, 1736–1749], was modeled in terms of probability density functions (PDFs) of three finite attribute groups (385 cores, 2 intercore linkages, and 194 side chains) and a PDF for each of a cluster-size and binding site distribution. These attributes, or molecule building blocks, represent more than 0.4 M molecules. An attribute reaction network was developed using the fundamental reaction chemistry for resid pyrolysis including 6274 reactions that fall into one of 11 reaction families. To make solution time tractable, we used attribute reaction modeling (ARM) which constrained the number of material balances to the number of attributes and i...