Towards a better understanding of transient processes in catalytic oxidation reactors

Light-off of the partial oxidation of methane to synthesis gas on a rhodiumcoated
cordierite honeycomb monolith at short contact times is studied
experimentally and numerically. The objective of this investigation is a better
understanding of transient processes in catalytic oxidation reactors. The
numerical simulation predicts the time-dependent solid-temperature distribution
of the entire reactor and the two-dimensional flow fields, species concentrations,
and gas-phase temperature profiles in the single channels. A detailed reaction
mechanism is applied, and the surface coverage with adsorbed species is
calculated as function of the position in the monolith. During light-off, complete
oxidation of methane to water and carbon dioxide occurs initially. Then,
synthesis gas selectivity slowly increases with rising temperature. The
numerically predicted exit temperature, conversion, and selectivity agree well
with the experimentally derived data.