Hydrotreating process kinetics for bitumen and bitumen-derived liquids

摘要

Hydrodenitrogenation, hydrodesulfurization and resid conversion data for the Whiterocks bitumen and bitumen-derived liquid were analyzed using a modified power rate law model. The model incorporated the space velocity and pressure since the plug flow equation may not be applicable to laboratory-scale reactors in which complete wetting of the catalyst may not be attained. The data were obtained with the reactor operating as a fixed bed reactor in the upflow mode. The space velocity (WHSV{sup {alpha}}) term was included to account for deviations from plug flow behavior. The exponents (a,p) and the kinetic parameters were obtained by combined non-linear regression and ODE solver techniques for the analysis of laboratory data. A simple nth order power rate law expression for hydrodenitrogenation and hydrodesulfurization was examined. The higher than first order kinetics for hydrodenitrogenation and hydrodesulfurization of the bitumen and bitumen-derived liquids were explained by invoking two parallel first-order reactions; one slow and the other fast. Parallel and consecutive reaction schemes were used to examine the extent of conversion of the resid fraction to middle distillate, gas oil and gasoline and the apparent kinetic parameters were determined. It was determined that the upflow operating mode was preferred to the trickle-bed mode in the laboratory reactor to insure plug flow behavior.