Design and Evaluation of a Co-Mo-Supported Nano Alumina Ultradeep Hydrodesulfurization Catalyst for Production of Environmentally Friendly Diesel Fuel in a Trickle Bed Reactor.

Abstract

In the present work, a nanocatalyst, γ-Al2O3 nanoparticle-supported CoMo, was prepared experimentally and evaluated through a hydrodesulfurization (HDS) process for removing dibenzothiophene (DBT) from diesel fuel systematically in a trickle bed reactor (TBR). The results of the prepared catalyst characterization tests (scanning electron microscopy, X-ray diffraction (XRD), XRD phase quantification, and Brunner–Emmett–Teller) showed good distribution of active metals (CoMo), difference in surface morphology, and high dispersion of active metals. The catalyst exhibited good metal–support interactions without impacting the surface area significantly. A fully automated TBR reactor was used to evaluate the activity of the prepared catalyst in the HDS process at ranges of operating conditions: temperatures (250–350 °C), pressures (6–10 bar), liquid hourly space velocities (LHSV) (1–3 h–1), and the activity of the prepared catalyst were compared to a commercial catalyst based on Co–Mo/γ-alumina. The results showed an obvious enhancement in the HDS process using the homemade nanocatalyst compared to the commercial catalyst. It has also been found that an increase in temperature led to an increase in the conversion from 68.77 to 91.57%, a little positive effect on conversion when pressure was increased, and a significant decrease in conversion (from 91.57 to 75.58%) as LHSV was increased. A kinetic model was developed for the HDS process to estimate kinetic parameters and apply the parameters in reactor design. The developed model showed that the DBT concentration in diesel fuel can be reduced significantly, 3000–240 ppm, at the optimum experimental conditions.