(509v) Molten-Salt Mediated CO2 Capture and Utilization for Ethane Oxidative Dehydrogenation with Super-Equilibrium CO2 Conversion

CO₂-mediated oxidative dehydrogenation (CO₂-ODH) of ethane represents a promising method for carbon dioxide utilization. Existing CO₂-ODH has yet to demonstrate >50% single-pass CO yield with coke due to the intrinsic equilibrium limitations for the CO₂-ODH reactions. We report a unique approach with mixed molten carbonates as reaction media for CO₂-ODH, which strategically partitions the CO₂-ODH reactions into gas and molten-salt phases and facilitates integrated CO₂ capture from power plant flue gases. Consequently, 89% CO yield was achieved at 770 ÌŠC, doubling the equilibrium limitation. The high CO yield in turn enhances ethylene formation. Further characterizations confirm that molten-salt mediated ODH (MM-ODH) proceeds through a gas-phase cracking and molten-salt mediated reverse water-gas-shift reaction pathway. Based on this understanding, general principles to optimize the molten-salt reaction medium were developed. Thermodynamic analysis further revealed the principle for molten salt selection. Process analyses confirmed that MM-ODH has the potential to be significantly more efficient for CO₂ capture and utilization than conventional CO₂-ODH.