Simultaneous conversion of carbon dioxide and methane to syngas using an oxygen transport membrane in pure CO2 and CH4 atmospheres

The utilization of CO2, coupled with partial oxidation of methane (POM) by using an oxygen transport membrane, has been investigated. The stability of both the membrane itself and the coating layers was simultaneously considered to develop a highly stable membrane under pure CO2 and CH4 conditions. The chemically stable La0.8Ca0.2FeO3−δ (LCF) and Ce0.9Gd0.1O2−δ (GDC) composite was used as the membrane. The LCF–GDC composite and NiO–GDC–LST (La0.3Sr0.7TiO3−δ) composite were adopted as the coating layer for CO2 reduction (feed side) and methane conversion (permeate side), respectively. A higher production of CO from CO2 was obtained in a pure CO2 atmosphere. Furthermore, CH4 was selectively converted to synthesis gas with 100% CO by adopting coking resistance on the coating layer. Using this chemically stable dual-phase membrane, 13.6 mL cm−2 min−1 of synthesis gas was produced at the permeate side, and the membrane was extremely stable over more than 100 h at 900 °C. These results suggest the potential possibility for the application of CO2 utilization coupled with methane conversion by using an oxygen transport membrane under a pure gas atmosphere to real industrial applications.