Hydrogen production by catalytic partial oxidation of iso-octane at varying flow rate and fuel/oxygen ratio: From detailed kinetics to reactor behavior

Hydrogen production by catalytic partial oxidation of iso-octane is experimentally and numerically studied over a rhodium/alumina coated honeycomb monolith at millisecond contact times by varying both fuel-to-oxygen ratio and flow rates and at varying flow rates. At fuel rich conditions, the formation of by-products potentially serving as coke precursors is observed. The quantity of by-products strongly depends on the flow rate. Both fuel conversion and hydrogen yield increase with increasing flow rate, i.e., decreasing residence time. This extraordinary behavior of autothermally operated short-contact time reactors can be understood by the interaction of mass and heat transport and chemical reactions. Therefore, an elementary-step-like heterogeneous reaction mechanism is implemented into a two-dimensional flow field description of a single monolith channel, coupled with a heat balance of the entire monolithic structure.

. Hydrogen production by catalytic partial oxidation of iso-octane is experimentally and numerically studied over a rhodium/alumina coated honeycomb monolith at millisecond contact times both at varying fuel-to-oxygen ratios and at varying flow rates. At fuel rich conditions, the formation of by-products potentially serving as coke precursors is observed. The quantity of by-products strongly depends on the flow rate. Both fuel conversion and hydrogen yield increase with increasing flow rate, i.e., decreasing residence time. This extraordinary behavior of autothermally operated short-contact time reactors can be understood by the interaction of mass and heat transport and chemical reactions. Therefore, an elementary-step-like heterogeneous reaction mechanism is implemented into a two-dimensional flow field description of a single monolith channel, coupled with a heat balance of the entire monolithic structure.Figure optionsDownload high-quality image (44 K)Download as PowerPoint slideResearch highlights▶ CPOX of iso-octane on Rh is experimentally and numerically studied at varying flow rates and C/O ratios. ▶ The quantity of by-products strongly depends on the flow rate. ▶ Heat loss has a high impact on conversion and H2 yield and can be understand using detailed modelling.