Feasibility study of the oxidative dehydrogenation of ethane in an electrochemical packed-bed membrane reactor

The feasibility of the oxidative dehydrogenation of ethane to ethylene with alumina-supported vanadium oxide catalyst (VOx/gamma-Al2O3) in an electrochemical packed-bed membrane reactor was investigated at temperatures between 500 and 620 degrees C with molar ratios of oxygen to ethane of 0.06-3.10. An oxygen-ion-conducting yttria-stabilized zirconia (YSZ) membrane was employed in a reactor of Au vertical bar YSZ vertical bar Pt, and the oxygen flux transferred across the membrane was controlled over the faradic coupling of oxygen-ion conduction and the external current between the electrodes. The oxidative dehydrogenation of ethane with electrochemically supplied oxygen in the membrane reactor was compared to that obtained with gaseous dioxygen in a conventional packed-bed reactor. The selectivity to ethylene was found to decrease as a function of supplied oxygen in both investigated operating modes. For all investigated oxygen/ethane molar ratios, the selectivity ratio, S-CO2/S-CO, was found to be clearly higher in the electrochemical than in the packed-bed reactor mode. The electrochemical oxygen supply significantly promoted CO2 formation, whereas the ethane conversion and ethylene selectivity were almost equal in the two investigated reactors. The experimental results indicate that, in the electrochemical operation, additional oxygen species exist in the system and are especially reactive in the total oxidation reactions.