Optimization of a counter-flow microchannel reactor using hydrogen assisted catalytic combustion for steam reforming of methane

• Catalytic combustion of hydrogen was applied in a micro steam reformer.
• After start-up by hydrogen catalytic combustion, fuel was changed to methane.
• The hydrogen flow rate was optimized using the response surface methodology.
• The optimal hydrogen flow rate guaranteed rapid start-up and stable fuel transition.
• The operating characteristics were compared between the co- and counter-flow reactors.

The objective of this study is to optimize a microchannel reactor using hydrogen assisted catalytic combustion for steam reforming of methane. Hydrogen assisted catalytic combustion does not require preheating because the catalytic combustion of hydrogen occurs at room temperature. After start-up by hydrogen catalytic combustion, fuels of hydrogen and methane were changed to methane. The geometric configuration of the counter-flow reactor was optimized by the simulation model under steady state condition. The hydrogen flow rate in the counter-flow reactor was also optimized by transient simulations using the response surface methodology. As a result, the counter-flow reactor showed extremely short start-up time because of the optimized configuration and the optimized hydrogen flow rate. Hot spots were avoided because of the hydrogen shut-off after start-up. The operating characteristics of the counter-flow reactor were compared with those of the co-flow reactor.