Hydrogenation of polycyclic aromatic hydrocarbons over Pt/γ-Al2O3 catalysts in a trickle bed reactor

Abstract

This work aims to investigate the effect of the amount of platinum loading on the hydrogenation of polycyclic aromatic hydrocarbons (PAHs) included in pyrolysis fuel oil (PFO) over Pt/γ-Al2O3 catalysts for the production of jet fuel. Catalyst characterizations were conducted by means of nitrogen adsorption, temperature-programmed desorption of ammonia, and temperature-programmed reduction under a hydrogen flow. The catalytic performance of bead-type Pt/γ-Al2O3 catalysts during the hydrogenation of PAHs included in PFO-cut was evaluated in a trickle-bed reactor. The main components produced by the hydrogenation reaction are decalin derivatives, alkylated cyclohexane, hexahydroindan derivatives, and bicyclohexyl. The cracking reaction was accelerated at the same time as the hydrogenation reaction over the Pt(1.0 wt%)/γ-Al2O3 and Pt(2.0 wt%)/γ-Al2O3; hence, the carbon number distribution shifted to the lighter side. The Pt(1.0 wt%)/γ-Al2O3 catalyst showed the highest activity during the hydrogenation of PFO-cut, which is attributed not only to the highest mesoporosity but also to the highest Pt dispersion. Catalyst deactivation could be ignored over the Pt(1.0 wt%)/γ-Al2O3 catalyst during ten hours of time-on-stream. The optimal reaction temperature and space velocity of PFO-cut to maximize the conversion of PAHs were determined to be 300 °C and 1.0 h−1, respectively.