An experimental and theoretical investigation of a catalytic membrane reactor for the oxidative dehydrogenation of methanol

The catalytic oxidation of methanol was investigated employing a tubular wa ll reactor to elucidate reaction kinetics and a membrane reactor to record performance. The membrane reactor consisted of a composite multilayered cer amic tube impregnated with platinum catalyst and housed within a shell of s tainless steel construction. Thermodynamic calculations and catalyst activi ty experiments revealed that hydrogen is a main product of reaction for mix tures rich in methanol and lean in oxygen for temperatures up to 300 degree sC and 1 bar pressure. Kinetic experiments indicated that two separate path ways yielding hydrogen were prevalent: a catalytic dehydrogenative oxidatio n giving H-2 and CO2 as products and complete catalytic combustion giving C O2 and H2O. Further experimental measurements using the catalytic membrane reactor showed that hydrogen as product could be partially separated from t he reaction products by the action of the ceramic membrane. a comprehensive theoretical model of the membrane reactor was constructed using Maxwell-St efan equations, the dusty gas model and differential energy balances. Resul ts of the theoretical investigation utilising the kinetic parameters found by experiment indicated reasonably good agreement between theory and experi ment. However, it was also clear that using a ceramic membrane impregnated with catalyst is not an efficient way to achieve H, separation during react ion on account of the ability of H, under the prevailing reaction condition s to diffuse in opposite directions simultaneously. (C) 2001 Elsevier Scien ce Ltd. All rights reserved.