Perpustakaan Digital ITB

As global mean temperature increases, attention is now being paid to the benefits of developing carbon capture, utilization, and storage (CCUS), which can be critical for mitigating climate change. The mineral carbonation process offers the possibility of storing CO2 permanently and safely. Fly ash is a potential source of highly reactive feedstock for CO2 mineral carbonation. It does not require pre-treatment processes and is produced in large volumes annually from coal-fired power plants. Still, it has a low carbonation rate and efficiency. To address these issues, the carbonation performance and mechanism of fly ash, together with the CO2 capture process by KOH, was studied in this research. The effects of temperature, ash concentration, and reaction duration on the carbonation efficiency were systematically investigated from the results of the semi-batch carbonation experiment. In addition, a repeated carbonation reaction and solvent regeneration were studied in the multi-cycle carbonation experiment. The result indicated that calciumbearing phases in the fly ash (lime, anhydrite, and brownmillerite) reacted with CO2, forming calcium carbonate with a maximum theoretical CO2 sequestration capacity of 0.108 kg CO2/kg fly ash. Increasing the ash concentration and reaction temperature during the carbonation process positively affects the sequestration rate and carbonation efficiency. The multi-cycle experiment showed that K2CO3 from the capture solvent facilitated the precipitation of CaCO3 and was well regenerated in the process. The estimated cost for CO2 sequestration with this method is around US$140.4/tCO2. We conclude that fly ash CO2 sequestration development is technically viable and economically competitive compared to others. Still, more CCUS-specific policies are recommended to ensure its development, especially in Indonesia.