Limestone Modified By Carbon Additives to Enhance the Sequestration of CO2 in Cement Industry

Global warming caused by CO₂ is a world problem and scientists have devoted themselves to the study of Carbon dioxide (CO₂) capture and sequestration (CCS). CCCR technology (a Ca-based sorbents Cycling Calcination/ Carbonation Reaction technology) is a kind of new and effective method to capture CO₂ in flue gas from industry. Limestone as a raw material in cement industry was used for sequestrating the CO₂. But its efficiency was dramatically reduced after several cycles due to the “sintering” phenomena. Here we have provided a new method to enhance the CO₂ sequestration ability of limestone by using small amount of carbon as an additive. carbon was used as skeleton at the early stage, then small pores were left and the specific area of limestone was increased when carbon was burned up. So the sintering was delayed and the calcination/carbonation rate was increased. A variety of carbon, such as carbon black, graphite, bamboo woods and coconut woods were studied. Our results show that coconut woods is the best carbon source and it has the performance of 13% increasment of efficiency with 2 wt% adding amount.