LAUSR

Abstract Energy-intensive endothermal gas phase reactions such as methane steam reforming constitute an essential class of chemical processes that provide feedstocks for the chemical industry. Autothermal reactor designs that couple endothermal reforming with exothermal combustion reactions are an effective means of process intensification towards a more sustainable production. Besides a proof of these reactor concepts, however, there is a need for optimization of the reactor design and operating parameters. Using a high-fidelity first-principles reactor model that includes the solution of the radiative transfer equation the optimal design of an autothermal channel reactor is identified emphasizing the heat transfer inside the reforming compartment. A two-step approach is proposed starting with the design of the reforming side followed by the design of the combustion side with two-compartment model. Highest product purity in combination with minimum heat transfer barriers dominated by conduction is achieved with a microchannel reactor with widths up to few millimeters. An increase in catalyst productivity, however, is only achieved with a reactor width of 8 mm and more where radiative heat transfer becomes significant. A technological optimal design is thus subject to the plant and economical constraints at a specific site and therefore balancing of purity, energy efficiency and productivity is required in any given scenario.