Hydrotreating stands as a critical facet in oil refining to meet stringent environmental norms, facilitating the production of ultra-low sulfur fuels. This study delves into the concurrent hydrodesulfurization of DBT and 4,6-DMDBT utilizing a NiMoP/Al2O3 catalyst. Through 27 experiments, parameters such as temperature, pressure, concentrations, and WHSV were scrutinized to derive kinetic insights. Employing five power law (PL) models, encompassing both global and individual HDS variations, parameter estimation employed weighted least squares optimization techniques like particle swarm and Gauss-Newton methods. Rigorous statistical analyses underlined model performance nuances. While the ‘global HDS of 4,6-DMDBT’ model met the chi-squared test, the ‘global HDS of DBT’ revealed complexities beyond PL modeling. Notably, the negative hydrogenation order for DBT implied significant adsorption effects. Apparent activation energies, approximately 117 kJ mol−1 for DBT and 124 kJ mol−1 for 4,6-DMDBT, were discerned using global models. •Deep hydrodesulfurization of DBT and 4,6-DMDBT was evaluated in fixed-bed reactor.•Estimation and statistical evaluation of kinetic parameters were performed.•A power-law model considering individual DBT routes fits the experimental data well.•The reparameterization technique and Arrhenius equation optimization reduced parametric correlation.