Kinetics of hydrocracking and hydrotreating of coker and oilsands gas oils

Two-stage hydrocracking of gas oils involves a complex set of hydrogenation, heteroatom removal, and cracking reactions. Feeds from coking processes and oilsands bitumen are richer in aromatics and heteroatoms, which increases the importance of the reactions of these components. The hydrocracking and hydrotreating kinetics of a series of conventional, coker and oilsands gas oils were measured using a laboratory microreactor. The kinetics were then correlated with the composition of the feed oils. The conversion of gas oil to middle distillate during hydrotreating was correlated with sulfur content and polyaromatic hydrocarbon content. Hydrocracking of the gas oil in the second stage of reaction followed a Langmuir-Hinshelwood rate expression based on the inlet concentration of total nitrogen. The resulting composite rate expression gave good prediction of gas oil conversion kinetics for the full range of gas oils. The inhibition of hydrocracking by nitrogen was more important for cracking than the differences in the homologous series in the gas oils of different origins.