Coupling CO2 separation with catalytic reverse water-gas shift reaction via ceramic-carbonate dual-phase membrane reactor

Abstract

Coupling of CO2 separation and CO2 utilization in membrane reactor is an ideal way to solve CO2 emission problem. In this study, we report an effective catalytic reverse water-gas shift (RWGS) process to produce CO with simultaneous CO2 capture from CO2-containing gas mixture using a ceramic-carbonate dual-phase membrane in a single reactor. The dual-phase membrane is comprised of a ceramic phase of oxygen-ion conductor and molten carbonate phase. The catalytic bed contains a LaNiO3 (LNO) or La0.9Ce0.1NiO3-δ (LCNO) catalyst. The RWGS reaction process can be catalytically activated by a single membrane without additional catalyst. CO2 permeation flux of the separation process and CO2 conversion of the RWGS reaction display significant increase after packing with catalysts in the membrane reactor. The results show that the reactor with LCNO catalyst generally precedes the LNO counterpart in CO2 conversion rate and the CO production yield. The membrane reactor yields a CO2 flux of 4.25 ml min−1 cm−2, which is around 4 times higher than that of the single membrane separation with pure He sweep gas. A CO2 conversion of 56.8% and a CO production rate of 2.41 ml min−1 cm−2 can be obtained at 750 °C using the membrane reactor with LCNO catalyst. Long-term stability test shows no obvious sign of degradation within 70 h. Overall, this work presents the technical exploration of a combined CO2 capture and conversion membrane-reactor for RWGS reaction process.