Kinetics for the partial oxidation of methane on a Pt gauze at low conversions

Intrinsic kinetics of the catalytic partial oxidation of methane were studi ed at atmospheric pressure in the presence of transport limitations using a single Pt gauze. Catalyst temperature and gas-phase temperatures were meas ured directly. CO, CO2, and H2O were the main products at catalyst temperat ures between 1,030 and 1,200 K, residence times of 0.02 to 0.2 ms, CH4/O-2 ratios between 1.8 and 5.0, and O-2 conversions between 9 and 46%. A kineti c model was developed that consists of six reaction steps. Methane adsorpti on had to be considered as oxygen-assisted to describe the experimental dat a, in particular the decrease of the selectivity for CO with increasing spa ce times. Corresponding intrinsic kinetic parameters were obtained from the literature and from regression of the experimental CO selectivities. The c alculated conversions and selectivities were obtained using the intrinsic k inetic model, together with a reactor model accounting for no transport lim itations quantitatively without any adjustable parameter. Simulations indic ate initial CO selectivities between 86 and 96% over the investigated range of conditions, and illustrate the relevance of both surface kinetics and m ass transport in CO formation.