Analysis of catalytic partial oxidation of methane on rhodium-coated foam monolith using CFD with detailed chemistry

CFD simulation with detailed chemistry was conducted to understand the catalytic partial oxidation of methane (CPOM) on rhodium-coated foam monolith. For the underlying process occurred extremely fast with large gradients of temperature and species concentrations at the inlet, special attention must be paid to the appropriate treatment on computational geometry and corresponding boundary conditions for the simulation. Discussions were made carefully on this proposed issue in geometry modeling that the reliable predictions can be authentically obtained by adopting the same geometry as the experiments from the viewpoint of physics in order to fully consider the heat conduction/diffusion at the reactor inlet. The right model system was sufficiently validated by both the conceptual analysis and the experimental results. The reactor performance of CPOM process was thereafter studied by numerically revealing the effects of wall heat conduction, the channel diameter and the catalytic surface area on the profiles of temperature and species concentrations. The results showed that the maximum wall temperature, which was crucial for the catalyst stability, could be significantly reduced by increasing the thermal conductivity of the wall, and/or the channel diameter, and/or the catalytic surface area, but accompanied with a slight drop of the methane conversion. This deficiency can be retrieved by decreasing the atom feed ratio of C/O and/or elongating the catalytic bed. These results pointed out the necessity of facilitating the foam material, the channel diameter and the catalytic surface area with the operating conditions in order to achieve the best performance of the CPOM process in the millisecond reactor. (C) 2009 Elsevier Ltd. All rights reserved.