Mathematical modeling of a slurry bubble column reactor for hydrodesulfurization of diesel fuel: Single- and two-bubble configurations

• Mathematical model for HDS of diesel fuel in slurry bubble column reactor developed.
• The transient mathematical model based upon single and two bubbles configuration.
• DBT, BPH, CHB and BCH considered as the four main sulfur-contained reactants.
• The modeling results revealed more than 98% of sulfur removal for the two models.
• The effects of operating parameters including; T and sulfur conversion discussed.

In this investigation, a mathematical model for HDS of diesel fuel in a slurry bubble column reactor was developed. The model is based on the axial dispersion of the heterogeneous gas flow regime, which includes two various bubble classes: large (20 ± 70 mm) and small (1 ± 10 mm). By assuming only large or large plus small bubbles in the column, single- and two-bubble class mode equations are developed. The developed models to solving the mass and enthalpy balances from which the sulfur conversion was obtained that undertaken. The chemical kinetics over NiMoS/γ-Al2O3 catalyst were undertaken for the reaction rate of the involved reactions. The reactor operating conditions including pressure of 50 bar at a temperature of 350 °C, inlet superficial gas velocity of 0.1 m s−1, and liquid velocity of 0.005 m s−1 were chosen. The obtained modeling results revealed 99.53% and 98.95% of sulfur removal for single- and two- bubble classes, respectively. Furthermore, the results of the two models compared satisfactorily with experimental data from open literature, and a collation utilizing empirical data between the two hydrodynamic models demonstrated that the two-bubble model was more compatible with the empirical data than the single-bubble model. The results of modeling including temperature variations, other reactor characteristics and conversion of desired product were discussed throughout in this research in detail.