A three-phase heterogeneous model was developed to simulate the performance of pilot-plant and industrial trickle-bed reactors applied to the hydrodesulfurization of diesel fractions. The model is based on two-film theory and incorporates mass-transfer phenomena at the gas−liquid and liquid−solid interfaces. The major hydrotreating reactions, namely, hydrodesulfurization, hydrodenitrogenation, hydrodearomatization, saturation of olefins, and hydrocracking, were modeled. Detailed pilot-plant experiments were carried out in a continuous-flow trickle-bed reactor using feedstock and catalyst samples collected from an industrial reactor to determine kinetic parameters and to validate the model under various operating conditions. The reactor temperature was varied from 320 to 360 °C and the liquid hourly space velocity from 1.0 to 2.5 h-1 at a constant operating pressure of 4.0 MPa and a H2/oil ratio of 200 L/L. The three-phase heterogeneous model was solved to estimate kinetic parameters for various hydrotreating reactions using the data generated in pilot-plant experiments. A partial wetting model was proposed to account for incomplete wetting of the catalyst particles in pilot-plant reactors. The model simulations were found to agree well with the experimental data in the range of operating conditions studied. A three-phase nonisothermal heterogeneous model with complete catalyst wetting was applied to simulate the performance of an industrial reactor under various operating conditions using the kinetic parameters estimated from pilot-plant experiments. Temperature profiles in the industrial reactor were generated. The model was found to simulate the performance of the industrial reactor adequately. The model was also applied to study the influence of operating conditions such as reactor temperature and feed rate on product quality.

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