A study on the CO2 capture and attrition performance of construction and demolition waste

CaO-based sorbent deactivation is one of challenges to develop CaO-based chemical looping technology. The replacement of non-renewable natural or expensive synthetic CaO-based sorbents with cheap and environmental CaO-based waste sorbents is an effective way to overcome this challenge. As high CaO content, construction and demolition waste (CDW) has ability to capture CO2. Due to the rapid development of cities, a great deal of CDW is produced every year. According to the characteristics of CDW, six components were selected in this paper. From the initial CO2 carrying capacity, hydrated limestone had the highest initial CO2 carrying capacity, about 0.592 g CO2/g sorbent in TGA and 0.414 g CO2/g sorbent in fluidized bed system, followed by limestone, cement- based limestone, hydrated cement, cement-based sand, cement raw and sand. For multiple carbonation-calcination cycles, cement played a positive role in maintaining high cyclic CO2 carrying capture. Hydration degree and free lime content increased with the increase of hydration time, which improved the CO2 capture performance of CDW. For cement-based sorbents, evidence from this study suggested that extending hydration time played a positive role in improving the attrition resistance and maintaining the initial specific surface area in fluidized bed system.