Hydrotreating heavy oils over a commercial hydrodemetallation catalyst

A Uinta Basin bitumen was hydrotreated over a sulfided Ni-Mo on alumina commercial hydrodemetallation catalyst. The catalyst was on-stream continuously for more than 1,000 hours. The data were obtained with the reactor operating as a fixed bed reactor in the upflow mode to ensure complete wetting of the catalyst and nearly isothermal operation.; The deactivation of the catalyst was monitored by the decline in the API gravity of the total liquid product with time-on-stream at a standard set of conditions. The primary process variables studied were reactor temperature (620-685 K; 656-775{dollar}spcirc{dollar}F), liquid weight hourly space velocity (0.24-1.38 h{dollar}sp{lcub}-1{rcub}{dollar}) and total reactor pressure (11.3-16.7 MPa; 1634-2423 psia). The hydrogen/oil ratio was fixed in all experiments at 890 m{dollar}sp3{dollar}/m{dollar}sp3{dollar} (5000 scf H{dollar}sb2{dollar}/bbl).; The extent of heteroatom and metals removal, residuum ({dollar}>{dollar}1000{dollar}spcirc{dollar}F) conversion and molecular weight reduction were determined as a function of process operating variables. Simulated distillation of the hydrotreated total liquid products was used to compute residuum conversion and product distributions. Conradson carbon residue conversion and pour point reduction were also determined as functions of process operating conditions.; Hydrodenitrogenation, hydrodesulfurization, hydrodemetallation and residuum conversion data were analyzed using a modified power rate law model. The apparent kinetic parameters were obtained by combined nonlinear regression and ordinary differential equation solver techniques for the analysis of laboratory data. Simple first-order power rate law expressions for hydrodenitrogenation and hydrodesulfurization were obtained for bitumen hydrotreating over the hydrodemetallation catalyst. Higher than first-order kinetic data for residuum conversion and nickel removal were organized by invoking two parallel first-order reactions for the facile and refractory fractions. A molecular weight reduction model was proposed to examine the extent of residuum conversion to gas-oil, middle distillate and gases. The first-order rate constants were also determined.; The hydrodemetallation catalyst was less active for nitrogen, sulfur and residuum conversion than the hydrodenitrogenation catalyst. Nitrogen, sulfur, and metals removal; residuum conversion; and product distributions are discussed for bitumen hydrotreating over the hydrodemetallation and hydrodenitrogenation catalysts.