Aging study of low Ru loading dual function materials (DFM) for combined power plant effluent CO2 capture and methanation

This work addresses the stability of different Ru-based dual function materials (DFM, x% Ru, 6.1% “Na2O”/Al2O3) during cycles of CO2 capture from simulated power plant effluent (320 °C; 7.5% CO2, 15% steam, 4.5% O2, balance N2 (v/v)) and subsequent catalytic methanation. Aging studies are carried out to simulate natural gas combustion flue gas on DFM granules, tablets, and ring tablets prepared by sequentially impregnating Ru and Na2O. Stability increases with Ru loading; however, 0.5% Ru DFMs demonstrate a small but steady loss of CH4 produced per cycle consistent with deactivation of the Ru component likely due to exposure to high levels of O2 and steam in the flue gas. CO chemisorption, in-situ FT-IR, and transient microreactor studies all verify that there is loss in Ru active surface area, possibly due to sintering, which consequently results in lower methanating ability.