Synthesis of spherical CaO pellets incorporated with Mg, Y, and Ce inert carriers for CO2 capture.

Abstract

Sintering and elutriation are two main problems of the calcium looping process for high-temperature CO2 capture. In the process of CO2 capture, the operation temperature is generally higher than the Taman temperature, resulting in the agglomeration and sintering of the sorbents. The traditional sorbent powers need to be granulated for practical application in a circulating fluidized bed to avoid elutriation. By using a new agar-assisted technology to granulate CaO powder incorporated with Mg, Y, and Ce inert supports, the problems of sintering and elutriation can be mitigated within one step. The incorporated inert supports are uniformly dispersed in the CaO/CaCO3 particles as an inert scaffold, and the inert scaffold is used as a skeleton to resist sintering, alleviate its agglomeration phenomenon, and keep the specific surface area to a certain extent. The Ce-incorporated CaO pellets have been proven to exhibit the best carbonation conversion and sorption capacity. The sorption capacity of 10% CeO2-incorporated CaO pellets reached 0.574 g CO2/g sorbent, more than 43% higher than that of the pure CaO pellets. In addition, the effects of the solid-liquid ratio during the preparation stage on CO2 performance were also investigated, demonstrating that a solid-liquid ratio of 1:5 was the optimal ratio to produce satisfying sorbents. The mitigated sintering and achieved spherical CaO pellets greatly promote the practical application of the calcium looping process for CO2 capture.