DEHYDROGENATION OF ETHANE USING SOLID ELECTROLYTES AS MEMBRANE REACTOR

The membrane reactors using three kinds of ionic conductors have been constructed in order to control the oxidative dehydrogenation of ethane electrochemically (Fig. 1). SrCe0.95.Yb0.05O3-alpha, Yttria-stabilized zirconia (YSZ) and BaCe0.9Y0.1O3-alpha were employed as protonic, oxide ionic and their mixed ionic conductors, respectively. When ethane and air were introduced at 700-degrees-C into the anode and the cathode, respectively, and the direct current was passed through the reactor, the formation rate of ethylene became larger as the current density increased in all the reactors (Fig. 4). From the measurement of the anodic potential, one can speculate that the activation of ethane is based on the decrease in partial pressure of hydrogen in the pore of the anode (Fig. 5). The current efficiency for the formation of ethylene decreased in the order of SrCe0.95Yb0.05O3-alpha, BaCe0.9Y0.1O3-alpha and YSZ (Table 1). This order can be explained by the thermal energy generated by changing the entropy of proton in the anodic reaction (Fig. 6). On the other hand, the formation rate of carbon dioxide increased with increasing the basicity of ionic conductors (Table 1).