Molecular Modeling of Gas Oil Hydrodesulfurization

The hydrodesulfurization (HDS) process chemistry and reaction network have been modeled at the molecular level. The following sulfur compound types have been considered: mercaptans, sulfides, disulfides, thiophenes (T), benzothiophenes (BT), dibenzothiophenes (DBT), and their alkyl and hydrogenated derivatives. The steric and electronic effects of the alkyl side chain of thiophenic compounds (T, BT, and DBT) are taken into account. The dual-site mechanism o site for direct desulfurization and T site for hydrogenation on catalyst surface is incorporated; the corresponding dual-site LHHW formalism is constructed to describe the complex kinetics. A rigorous molecular model for gas oil HDS is thus developed fast and successfully by aid of the Kinetic Modeler's Toolbox (KMT). The model matches pilot plant data very well and can be used to optimize the HDS process.