Catalytic combustion of methane and propane in a fluidized-bed reactor

Fluidized bed combustion of premixed lean methane- and propane-air mixtures over a copper based catalyst has been studied. Fluidization behaviour of the catalyst particles, 1 mm diameter, is that typical of the B-D group of the Geldart classification of powders. Combustion experiments have been performed in a 0.10 m fluidized bed reactor with unexpanded bed height of 0.10 and 0.20 m. The influence of temperature (in the range 300 to 700°C), of gas superficial velocity, of the catalyst loading on the degree of fuel conversion has been assessed. A model of the fluidized bed combustor has been developed, based on the two-phase fluidization theory. The model has been particularized to the limiting case of low-temperature kinetic-controlled combustion rate in order to assess parameters of the intrinsic combustion kinetics from experimental data. Good agreement between model computations and experimental results is obtained throughout the range of operating variables investigated. The cooperative role of intrinsic kinetics and of intraparticle and interphase (bubble-to-emulsion phase, emulsion phase-to-catalyst particle) diffusional resistances is adequately taken into account. Model simulations have been further directed to highlight the controlling conversion regimes in the range of operating variables investigated.