Core‐shell structured CaO‐based pellets protected by mesoporous ceramics shells for high‐temperature CO2 capture

Abstract

AbstractIn this study, a series of core‐shell structured spheriform CO2 sorbents were synthesized by using CaO‐based pellets as cores and different mesoporous metal oxides (e.g. alumina, ceria, and yttrium‐stabilized zirconia) as shells through a repeated wet impregnation coating process. Cyclic CO2 capture performance of the obtained sorbents was investigated using a thermogravimetric analyzer. Among all the core/shell sorbents under study, the pellets coated with a layer of alumina exhibit the best performance in the retention of CO2 uptake over 20 cycles with the lowest activity loss of only 30.4 %, attributed to the existence of the thermal stable porous alumina shell which prevents the sintering and the aggregation of the CaO grains. Moreover, the attrition study using an air‐jet apparatus and a standard test method reveals that such sorbents exhibit enhanced attrition resistance due to the protection of the porous shell providing them with a great potential for application in fluidized bed conditions.