Size effect of calcium precursor and binder on CO2 capture of composite CaO-based pellets

The pelletization of CaO for calcium looping process(CLP) are highly desirable for post-combustion capture of CO 2 . The influence of particle size of the calcium precursor and binder on sorbent CO 2 capture performance were investigated. Different calcium precursors: limestone and nano CaCO 3 , and different binders: calcium aluminate cement, micro Al 2 O 3 and nano Al 2 O 3 were used for pellet preparation. After calcination, CaO mixed with calcium aluminate cements served to produce calcium aluminate (Ca 12 Al 14 O 33 ) pinning sites, acting as a thermally stable and mechanically hard support for CaO bulk. XRD and SEM showed that nano calcium precursor led to higher mayenite production and a homogeneous mixture of mayenite and CaO, having a perfect dispersion effect to avoid sintering. Durability studies showed that composite pellet with nano CaCO 3 /cement captured 0.20 gCO 2 /g calcined sorbent after 15 cycles, while the capacity of limestone/cement was only 0.14g/g. The influence of binder particle size was further investigated and nano CaCO 3 /nano Al 2 O 3 showed better CO 2 capture performance compared with calcium aluminate cement and micro Al 2 O 3 .