DEACTIVATION OF SUPPORTED NICKEL-CATALYSTS DURING THE REFORMING OF METHANE BY CARBON-DIOXIDE

Several supported nickel catalysts were tested for the methane reformi ng reaction at 700 degrees C. The initial activity is found to depend essentially on the state of the nickel phase (reduction and dispersion ) and little on its environment (support, additive). The product distr ibution is controlled by the WGS equilibrium. The zero order aging pro cess is mostly due to carbon deposition, though slight Ni sintering al so occurs. Among the deposited carbon, only a stable form, possibly ar ising from the CO disproportionation, would poison the Ni particles. A nother form, less stable and arising from methane activation, is rapid ly accumulated on the catalyst, but at a low level and limited extent.