Oxidative dehydrogenation of ethane over a perovskite-based monolithic reactor

The oxidative dehydrogenation (ODH) of ethane has been investigated in a short-contact-time reactor consisting of a LaMnO3-based monolithic catalyst with a honeycomb morphology. Using an ethane/air mixture with a C2H6/O-2 ratio = 1.5 and a preheat temperature ranging from 250 to 400degreesC results in a 55% ethylene yield, a value even higher than those reported in the same experimental conditions over Pt-based catalysts. By investigating the effect of the experimental conditions, we found that the major role of increasing the feed flow rate and decreasing the C2H6/O-2 ratio is to raise the degree of adiabaticity of the reactor and, consequently, ethane conversion and temperature. The selectivity to ethylene also seems to increase with increasing temperature, but only up to about 950degreesC. At higher temperatures, further degradation of ethylene to C2H2 and CH4 occurs. We also found that, unlike Pt monoliths, the perovskite catalyst is intrinsically active in ODH. (C) 2002 Elsevier Science (USA).