[Abstract]

The production of C2 hydrocarbons such as ethylene (C2H4) and ethane (C2H6) is important for the chemical industry. With the depletion of liquid petroleum, natural gas containing primarily methane (CH4) is expected to be one of the main resources for the C2 gas production. Oxidative coupling of methane (OCM) is an attractive route for direct conversion of methane to valuable chemicals, mainly C2 products. Nevertheless, the main barrier to commercialization of OCM is that the C2 yield is too low due to the deep oxidation of highly reactive products in operating condition. To overcome this challenge, considerable research efforts on OCM have been devoted to the development of ion-conducting ceramic membrane. In case of OCM using the ion-conducting membrane, oxygen permeates through the ceramic membrane and reacts with the methane on the membrane surface where conversion takes place, thereby selectively avoiding partial or complete oxidation of methane.

In this talk, I will present OCM for C2 hydrocarbon production using Zr-containing BaFeO3-δ membrane with lanthanum oxide (La2O3) as a catalyst in a fixed-bed configuration. BaFeO3-δ, a cobalt-free perovskite oxide, has been considered as a candidate membrane material for OCM due to its high oxygen permeability but it generally exists as a multiphase compound because of a mismatch in the ionic radius between Ba and Fe. Zr is introduced into Fe site for chemical stabilization of BaFeO3-δ in operating condition for OCM. Gas-phase analysis near the membrane is performed to suggest a global reaction mechanism for the conversion of methane to C2 products that accounts for gas-phase and surface reactions. Based on this, it is shown that OCM in a lab-scale membrane reactor is able to achieve a high yield of C2 under long-term operation without membrane degradation or catalyst deactivation.