Synthesis of calcium aluminates granule with TiO₂ binder for high-temperature CO₂ capture

High-temperature CO₂ captures using powder and granule is investigated using thermogravimetric analyzer (TGA) and fixed-bed reactor (FBR). The CO₂ sorbent, Ca-Al-CO₃ powder was prepared using co-precipitation method of Ca⁺², Al⁺³ and CO₃ ^2- under alkaline conditions. The granule was fabricated by mixing Ca-Al-CO₃ powder, H₂O and w/ or w/o TiO₂ binder, followed by granulation and calcinations at 600°C. In TGA experiment, high CO₂ capacity of 45∼50 wt% after 100 cycles can be achieved with powder at 750°C, while it was dramatically decayed to 40-50% only after 2-5 cycles in FBR. Alternatively, using Ca/Ti granule exhibited recovery of 80-90% for 15 cycles in TGA and 70-80% for 10 cycles in FBR, respectively. This outcome indicates that calcium aluminates granule with TiO₂ binder is competitive CO₂ sorbent.