CO2 Capture Using CaO Modified with Ethanol/Water Solution during Cyclic Calcination/Carbonation



The calcium-based sorbent cyclic calcination/carbonation reaction is an effective technique for capturing CO2 from combustion processes. The CO2 capture capacity for CaO modified with ethanol/water solution was investigated over long-term calcination/carbonation cycles. In addition, the SEM micrographs and pore structure for the calcined sorbents were analyzed. The carbonation conversion for CaO modified with ethanol/water solution is greater than that for CaO hydrated with distilled water and is much higher than that for calcined limestone. Modified CaO achieves the highest conversion for carbonation at the range of 650–700 °C. Higher values of ethanol concentration in solution result in higher carbonation conversion for modified CaO, and lead to better anti-sintering performance. After calcination, the specific surface area and pore volume for modified CaO are higher than those for hydrated CaO, and are much greater than those for calcined limestone. The ethanol molecule enhances H2O molecule affinity and penetrability to CaO in the hydration reaction so that the pores in CaO modified are obviously expanded after calcination. CaO modified with ethanol/water solution can act as a new and promising type of calcium-based regenerable CO2 sorbent for industrial applications.