Mathematical Modeling and Simulation of the Commercial Diesel Hydrotreating Reactor

A three-phase nonisothermal heterogeneous model for describing the hydrotreating reactions in a trickle-bed reactor with complete catalyst wetting was solved. It includes correlations for determining solubility data, mass-transfer coefficients, and properties of the compounds under operating conditions. The model, based on the two-film theory and mass-transfer resistance at the gas-liquid and liquid-solid interfaces. The different sulphur compounds were taken as a lump component in the diesel fuel. The sulphur concentration in liquid phase as well as hydrogen and hydrogen sulfide profiles were simulated along the bed. The sulphur content of the product was found to be strongly dependent on the gas/oil flow ratio in the reactor. This is due to the inhibiting effect of hydrogen sulfide which proved strong suppression of conversion rate of sulphur compounds. Therefore in present work, for hydrodesulphurization (HDS) reaction three kinetic models were considered and were tested for better product properties estimation. The model was validated with plant operating data and could predict the product sulphur content and reactor bed temperature profiles in commercial plant adequately.