KINETICS OF HYDROGEN CONSUMPTION DURING CATALYTIC HYDRODESULFURIZATION OF A RESIDUE IN A TRICKLE-BED REACTOR

A kinetic model for hydrogen consumption during catalytic residue hydrodesulfurization is presented. The intrinsic reaction rates are described by use of a second-order kinetic equation. The intraparticle diffusional effects are discussed by means of the effective diffusivity. Kinetic experiments were carried out in an isothermal trickle-bed reactor, in which two commercial Co-Mo/Al//2O//3 catalysts were used in a temperature range of 350-430 degree C, a liquid hourly space velocity ranging from 0. 25 to 3 h** minus **1, and a constant pressure of 50 multiplied by 10**5Pa. The remaining catalyst activity varied between 1. 0 and 0. 2. Crushed particles and cylindrical extrudates - for each type of catalyst - were used in experimentation. The atmospheric residue of Greek petroleum deposits in the Aegean Sea served as feedstock. Specific rate constants, activation energies and effective diffusivities were determined. Hydrogen consumption increased as either the remaining activity of the catalyst, the reactor temperature or the catalyst size decreased.