Sulfur tolerance and self-regeneration mechanism of Na-Ru/Al2O3 dual function material during the cyclic CO2 capture and catalytic methanation

The combined CO2 capture and methanation with Dual Function Materials (DFM) is emerging as a vibrant field of research for its potential to increase the efficiency and reduce the cost of current multistage CCU processes. In this work, we set out to investigate for the first time the impact of sulfur poisoning over a Na-Ru/Al2O3 DFM operated in a fixed bed reactor with alternate feeds under realistic conditions including the presence of SO2, H2O and O-2 in the process gas stream. The results of the extensive characterization of the fresh and sulfated (reaction -aged) DFM evidenced a remarkable intrinsic tolerance of the combined CO2 capture and methanation process to high concentrations of SO2 in the feed due to a self-regeneration mechanism of the Ru catalytic sites.