Porous spherical calcium aluminate-supported CaO-based pellets manufactured via biomass-templated extrusion-spheronization technique for cyclic CO2 capture.

Calcium looping has been proposed as one of the most promising technologies for CO2 capture to mitigate the growing problem of global warming. However, the loss in capacity and attrition are two issues lying on the way to practical application for calcium looping process. To improve CO2 capture performance and mechanical strength of CaO sorbents, a biomass templated extrusion-spheronization palletization technique was employed to manufacture porous calcium aluminate-supported CaO-based pellets. For the first time, this work investigated the granulation of calcium aluminate-supported CaO-based sorbents and also the effectiveness of three novel biomass-based pore-creating materials of straw, willow, and wheat. The results indicated that the incorporation of calcium aluminate-based supports could effectively enhance cyclic performance and stability. Besides, the 5 wt.% addition of pore-creating materials could further promote the cyclic CO2 capture capacity of calcium aluminate-supported CaO-based pellets. The pellets added with 25 wt.% calcium aluminate-based supports and 5 wt.% straw still held a good carbonation conversion of 46.45% after 50 cycles even tested under CO2-rich calcination atmospheres. In addition, the anti-attrition ability tests by friability tester (FT) demonstrated that all the prepared pellets owned an excellent degree of attrition (less than 1%). The good CO2 capture performance and mechanical strength endowed biomass-templated calcium aluminate-supported CaO-based pellets with promising prospects for practical CO2 removal.