KINETICS AND REACTION-ENGINEERING STUDIES OF DRY REFORMING OF METHANEOVER A NI LA/AL2O3 CATALYST/

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 reformin g was described by applying a Langmuir-Hinshelwood rate equation. The developed kinetics was interpreted with a two-phase model of a fluidiz ed bed. The predictions for a bubbling-bed reactor operated with an un diluted feed (CH4:CO2=1:1) at 800 degrees C showed that, on an industr ial 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 equil ibrium (X-CH4 = 88.2%, X-CO2 = 93.6%). The performance of the reactor was strongly influenced by the interphase gas exchange: the highest sp ace time yields were obtained for small particles (d(p) = 80 mu m).