High performance CaO-based sorbents for pre- and post- combustion CO2 capture at high temperature

Abstract

Synthetic CO2 sorbent materials of CaO/Ca12Al14O33 of different compositions were prepared using a simple hydrothermal method and low-cost hydroxides starting precursors. The products were characterized by X-ray diffraction, scanning electron microscopy, BET analysis and crushing tests. Sorption kinetics and chemical stability during carbonation/ calcination multi- cycling in pre- and post-combustion conditions were investigated by thermo gravimetric analysis. Long-term stability of the hydrothermally prepared sorbents is attributed to the formation of a stable frame of mayenite (Ca12Al14O33) which reduces the sintering of the active CaO phase. Among all sorbents, the one with composition 27/73 wt % CaO/Ca12Al14O33 is considered a promising CO2 sorbent with stable capture capacity (21g-CO2/100 g sorbent) in severe calcination conditions and high mechanical strength.