Ageing study of Li-Ru/Al2O3 dual function material during the integrated CO2 capture and methanation with SO2-containing flue gas

A Dual Function Material containing Ru (1% wt.) and Li (3% wt.) dispersed by sequential impregnations onto Al2O3 spheres was extensively tested in the integrated CO2 capture and methanation process to assess the effects of the main species (O2 and H2O) as well as of poisonous impurities (SO2) in realistic flue gases. The DFM designed in this work was benchmarked against the state-of-the-art formulation (Ru and Na) in terms of intrinsic methanation activity as well as CO2 capture capacity, CH4 production and selectivity across more than 100 repeated cycles performed in a fixed bed reactor operated in the temperature range 260–320 °C with alternate feed conditions. The ageing study with up to 100ppmv SO2 demonstrated a remarkable tolerance to sulfur poisoning coupled with a slow loss of CO2 capacity due to long-term S-accumulation. A detailed characterization of the fresh and S-aged DFM was performed to get insights into mechanistic aspects behind the peculiar self-regeneration characteristic of the catalytic sites in the DFM.