CFD simulation of isothermal diesel oil hydrodesulfurization and hydrodearomatization in trickle bed reactor

The computational fluid dynamics (CFD) technique was used to study the effect of operational parameters on hydrodesulfurization (HDS) and hydrodearomatization (HDA) conversion in a trickle bed reactor (TBR). The Eulerian-Eulerian multiphase approach with appropriate momentum and mass interphase interactions models were implemented to describe reactor performance. The porosity distribution was considered to account wall effect on interphase interactions through the reactor. The simulations were performed at partially wetted bed at different operational conditions (temperatures, pressures, liquid and gas velocities as well as hydrogen sulfide concentration in gas phase) with proposing new reactions constant to remove reactions dependency from wetting effects. Furthermore, simulations were repeated at fully wetted bed to consider hydrotreating reactions conversion at fully wetted conditions. The effect of operational pressure on pressure drop through the bed and influence of liquid velocity on hydrodearomatization conversion were studied. Furthermore, temperature effect on mass fractions of species (desulfurized components, hydrogen and hydrogen sulfide) and reaction rate of HDS and HDA reactions were considered at both partially and fully wetted conditions. Finally, influence of bed porosity distribution was investigated on the local velocity, HDS reaction rate and hydrogen interphase mass transfer through the bed.