Thermodynamic Aspects of Hydrodesulfurization and Hydrodenitrogenation

This article is a comprehensive review of the thermodynamics of hydrodesulfurization and hydrodenitrogenation, which are among the main classes of hydrotreating reactions. Available methods to estimate the thermodynamic data are reviewed and experimental data have been compiled and analyzed. The study shows that hydrodesulfurization and hydrodenitrogenation reactions as such are not severely limited thermodynamically. However, certain sulfur and nitrogen compounds are required to be hydrogenated before scission of heteroatom. These are aromatic hydrogenation reactions, which are thermodynamically limited under normal process conditions. Since the hydrotreating reactions occur simultaneously, there is a need to compute multi-reaction equilibria to elucidate the effects of one class of reaction on the thermodynamics and kinetics of the other.