Mathematical Modeling and Simulation of Hydrotreating (HDS, HDN and HAD) of Gas oil in Commercial Trickle-bed Reactor

A three-phase nonisothermal heterogeneous model for describing the hydrotreating (HDT) of diesel in a trickle-bed reactor is presented. The model, based on the two-film theory and mass-transfer resistance at the gas-liquid and liquid-solid interfaces. The different sulfur, nitrogen compounds were taken as lump components in the diesel fuel. In hydrotreating process, the sulfur, nitrogen and aromatic concentrations in liquid phase as well as hydrogen and hydrogen sulfide profiles were simulated along the bed. The sulfur 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 sulfur compounds. In present work, for hydrodesulfurization (HDS) reaction three kinetic models were considered and examined for the better product properties' prediction. The model was validated with outlet data of the industrial hydrotreating (HDT) trickle bed reactor and well predicted the product sulfur, nitrogen and aromatic contents and reactor bed temperature.