The effect of fly ash on reactivity of calcium based sorbents for CO2 capture

Calcium looping technology is considered one of the potential technologies for CO2 capture. However, the rapid decay in CO2 capture capacity of calcium based sorbents is still of great concern. To reduce the decay and maintain high performance of CO2 capture is extremely attracted by researchers, especially in an environmentally friendly way at low cost. Efforts have been made to seek an effective method to enhance CO2 capture performance of calcium based sorbents by use of coal fly ash. CO2 capture performance is improved for sorbents modified with fly ash after pretreatment such as grinding and calcination. Calcium based sorbents hydrated with fly ash under acidic condition present increased reactivity and achieve high CO2 capture capacity attributed to improved microstructure and formation of supporting products such as Ca12Al14O33 and CaSiO3, while sorbents modified under basic condition do not enhance CO2 capture performance but present more stability during calcination/carbonation cycles.