Hydrocracking Straight-Run Diesel into High-Value Chemical Materials: The Effect of Acidity and Kinetic Study

Abstract

A novel process of hydrocracking straight-run diesel was proposed for producing more chemical materials. The influences of acidities and hydrogenation abilities for serial bifunctional catalysts on hydrocracking behaviors for diesel were also investigated. The results showed that the acidities of catalysts increased with additional amounts of Y zeolite, and the hydrogenation abilities enhanced with the amounts of Al 2 O 3 due to its large pore size and pore volume, which could provide a preferable support colony for active metals to disperse. The X-ray photoelectron spectra (XPS) and high-resolution transmission electron microscopy (HRTEM) results demonstrated that the NiW/AY-15 catalyst had the highest proportion and dispersion degree of MoS 2 active phases. Meanwhile, the evaluation results of straight-run diesel hydrocracking exhibited that the light naphtha, jet fuel, and upgraded diesel with large amounts of paraffins could be directly applied as feedstock of the steam-cracking unit for producing olefins. The heavy naphtha with high amounts of aromatics and cyclanes could also serve as high-quality feedstock for the catalytic reforming unit. Therefore, the quantities of chemical materials were maximized through hydrocracking straight-run diesel. Moreover, the amounts of paraffins in the hydrocracking product of diesel over the NiW/AY-15 catalyst were the highest among all of the catalysts due to its best hydrogenation performance. Finally, the kinetic model and reaction characteristics of straight-run diesel hydrocracking were initially proposed on the basis of the experimental results. The kinetic analysis proved that hydrocracking of straight-run diesel followed the pseudo-first-order reaction.