Influence of the methane combustion kinetic model on the operating conditions of an autothermal catalytic reactor

This work focuses on the study of the influence of the methane combustion k inetics on the operation of an autothermal catalytic reactor for heat gener ation (domestic scale). The feed (methane and air) is preheated by means of a direct heat exchange by recycling a fraction of the hot gases leaving th e catalytic combustor (recycle monolithic reactor): Two kinetic models are proposed to represent the reaction. The kinetic parameters were adjusted us ing experimental data obtained from methane combustion over a laboratory ca talyst (Pd on gamma -Al2O3 wash-coated cordierite monolith). Experiments we re carried out for different feed temperatures (310-500 degreesC), total fl ow rates [250-750 cm(3)/min (STP)], and inlet methane concentrations (0.8-1 .6%). A heterogeneous unidimensional steady-state model was employed to ana lyze the autothermal reactor performance. Using the best-fitted reaction ra te expressions, conservative operating conditions are estimated to guarante e reactor stability, almost complete methane conversion (i.e., minimal unbu rned hydrocarbon emissions), and a high heat generation rate.