CO2 Sorption Enhancement of Extruded-Spheronized CaO-Based Pellets by Sacrificial Biomass Templating Technique

The sacrificial biomass templating technique was used to enhance the sorption performance of CaO-based pellets that were prepared via an extrusion-spheronization method. Five types of biomass materials were used as the templates: microcrystalline cellulose, corn starch, rice husk, sesbania powder, and lycopodium powder. It is found that the addition of biomass templates is effective to improve the cyclic CO2 sorption capacity of the CaO-based pellets. However, two opposite enhancement tendencies of CO2 uptake were observed with the increment of biomass addition. For microcrystalline cellulose, corn starch, and rice husk, more addition amounts would result in better improvement of CO2 sorption performance of the CaO-based pellets. It is attributed to the generated porous microstructure and large amounts of small grains. However, for sesbania powder and lycopodium powder, a decreasing enhancement tendency of the CO2 sorption performance was found with the increasing addition amount. It is probably due to the accelerated sintering of the sorbent because of the presence of excessive amounts of alkali metal elements. Moreover, all biomass-templated CaO-based pellets possess a high anti-attrition capacity.