Role of CO2 in Catalytic Ethane-to-Ethylene Conversion Using a High-Temperature CO2 Transport Membrane Reactor

The noncatalytic, thermo-dehydrogenation-based steam cracking is a benchmark technology for ethylene production from ethane or naphtha. However, this technology is energy- and emission-intensive. Aiming to develop low-energy and low-emission ethylene production technology, this work explores a new way to make ethylene with CO2 directly captured by a membrane reactor operated on bi-ionic CO32-/O2- chemistry. The performance of such a combined CO, capture and ethane conversion membrane reactor incorporated with a Cr2O3-ZSM-5 catalyst is promising. Through conversion studies under different conditions, we also unveil that the mechanisms of this membrane-based catalytic ethane-to-ethylene conversion are dominated by thermo-dehydrogenation of ethane, accompanied by concurrent reverse water gas shift (RWGS) and reverse Bouduoard (RB) reactions. With the catalyst, the active role of CO2 is to promote H-2 removal via RWGS, thus the production of ethylene and suppress coking via RB.