Kinetic and Reaction Engineering Studies of Dry Reforming of Methane over a Ni/La/Al₂O₃Catalyst

Kinetic studies of CO2 reforming of methane over a highly active Ni/La/alpha-Al2O3 catalyst were performed in an atmospheric microcatalytic fixed-bed reactor, The reaction temperature was varied between 700 and 900 degrees C, while partial pressures of CO2 and CH4 ranged from 16 to 40 kPa. From these measurements kinetic parameters were determined; the activation energy amounted to 90 kJ/mol. The rate of CO2 reforming was described by applying a Langmuir-Hinshelwood rate equation. The developed kinetics was interpreted with a two-phase model of a fluidized bed. The predictions for a bubbling-bed reactor operated with an undiluted feed (CH4:CO2=1:1) at 800 degrees C showed that, on an industrial scale, significantly longer contact times (H-mf = 7.8 m, m(cat)/V-STP = 31.8 g.s.mL(-1)) are necessary for achieving thermodynamic equilibrium (X-CH4 = 88.2%, X-CO2 = 93.6%). The performance of the reactor was strongly influenced by the interphase gas exchange: the highest space time yields were obtained for small particles (d(p) = 80 mu m).