Partial oxidation of n-butane in a solid electrolyte membrane reactor: Periodic and steady-state operations

An electrochemical membrane reactor using yttria-stabilized zirconia as a solid electrolyte membrane was applied to the selective partial oxidation of n-butane to maleic anhydride over a vanadium phosphorus oxide (VPO) catalyst. In this reactor, the oxygen required for anodic butane oxidation was generated by electrical oxygen pumping, i.e. by imposing an external current to the membrane reactor from anode to cathode. Periodic redox experiments, in which electrical oxygen pumping and butane oxidation were carried out sequentially, confirmed that the reduced activity of the VPO catalyst in the butane oxidation could be regenerated by electrical oxygen pumping. A series of steady-state experiments were carried out to assess the influence of operating conditions such as imposing current, reaction temperature, butane concentration and flow rate on the catalytic performance, where the electrochemical oxygen pumping and butane oxidation were performed simultaneously. The studied membrane reactor gave maleic anhydride yield of 10% with maleic anhydride selectivity up to 53% at reaction temperature of 753 K.