Enhancement of fast CO2Capture by a Nano-SiO2/CaO composite atCa-Looping conditions

In this paper we show the performance of a new CO2sorbentconsisting of a dry physical mixture of a Ca-based sorbent and a SiO2nanostructuredpowder. Thermo-gravimetric analysis (TGA) performed at conditions close to the Ca-looping process demonstrate that the rate of CO2capture by the mixture is enhancedduring the fast carbonation stage of practical interest in applications. Moreover, theresidual capture capacity of the mixture is increased. SEM/EDX, physisorption, andXRD analyses indicate that there is a relevant interaction between the nanostructuredSiO2skeleton and CaO at high temperatures, which serves to improve the efficiency ofthe transfer of CO2to small reactive pores as well as the stability of the sorbent porestructure