Sr2CeO4 as a robust high temperature sorbent for CO2 capture with near 100% sorbent conversion efficiency

Abstract

As a typical CO2 capture and storage (CCS) technology, sorbent looping CO2 capture (SLCC) can be incorporated into CO2-related processes to enable potential revenue. The main challenge of the SLCC is the poor reactivity stability and limited operation temperature of sorbent. High temperature sorbent of SrO was prepared with sol–gel method and the carbonation/calcination performance was evaluated in thermogravimetry. The effect of different support materials (Al2O3, Y2O3, MgO, CeO2 and ZrO2) on the reactivity stability was initially evaluated during 25 carbonation/calcination cycles. The CeO2 supported sorbent exhibited super stable CO2 capture performance, whereas other materials could not stabilize the sorbent reactivity over multiple cycles. Afterwards, the effect of CeO2 loading on the sorbent reactivity, microstructure and phase transition was further identified. The results indicate that the Ce-Sr interaction induced new decarbonation path of SrCO3 + CeO2 = Sr2CeO4 + CO2 instead of conventional thermal sorbent decomposition of SrCO3 = SrO + CO2. It promoted the reaction kinetic and enabled the carbonation/calcination at a lower temperature. Also, it improved the microstructure and the sintering resistance, promoting sorbent reactivity stability. The ratio of Ce/Sr higher than 0.5 was necessary to obtain a stable CO2 capture performance with almost 100% sorbent efficiency over multiple cycles.