Reaction engineering of the hydrogenolysis of liquid n-Alkanes: Comparison of flow and batch reaction systems

• The rates of C 36 H 74 hydrogenolysis over Ru/SiO 2 in a continuous flow and a batch reactor were compared. • The hydrogenolysis reaction was found to be negative order in H 2 pressure. • Transport of the H 2 through the liquid hydrocarbon phase to the catalyst surface is not rate limiting. • The formation of dry zones on the catalyst surface in the flow reactor causes lower overall reaction rates in the flow reactor compared to the batch reactor. Currently there is much interest in developing catalysts for the hydrogenolysis of long-chain alkanes for use in the recycling and upcycling of waste polyolefins. Understanding how reactor configurations affect reactivity and product distributions for this class of reactions is equally important. To aid in this effort, here we report a study of the hydrogenolysis of the alkane, n -hexatriacontane (C 36 H 74 ), over a Ru/SiO 2 catalyst in both batch and flow reactor configurations. For similar catalyst contact times and H 2 pressures, the C 36 hydrogenolysis rate was found to be significantly higher in the batch reactor compared to the flow reactor which can be attributed to H 2 bubbles forming inactive dry zones on the catalyst surface in the flow reactor which are less prevalent in the batch reactor. In both reactor systems the hydrogenolysis rate was found to be negative order in H 2 and that transport of the H 2 through the liquid phase to the catalyst surface was not rate limiting.