Recent progress in calcium looping integrated with chemical looping combustion (CaL-CLC) using bifunctional CaO/CuO composites for CO2 capture: A state-of-the-art review

• Potential applications of the CaL-CLC process were reviewed. • Simulation works of the CaL-CLC process were summarized. • Strategies proposed to improve cyclic CO 2 capture performance were presented. • Potential future research trends were recommended in this work. Calcium looping integrated with chemical looping combustion (CaL-CLC) process is an efficient and cost-effective CO 2 capture technology. In this technique, the heat generated by chemical looping combustion of CuO is used in-situ to calcine CaCO 3 , thus avoiding the implementation of the energy-intensive air separation unit (ASU) in the conventional calcium looping (CaL) process for postcombustion CO 2 capture. Many studies, including simulation works and material development, have been carried out on the CaL-CLC process. It is thus imperative to present the recent progress in the CaL-CLC process whilst providing a research prospects framework and direction for future research. First, fundamental understandings of the CaL-CLC process are discussed, including its concept and potential applications. Then, simulation work is reviewed, emphasizing process design and analysis, as well as modeling of the reactor and main reactions involved in the CaL-CLC process. Due to the fast reactivity decay of bifunctional CaO/CuO composites, various strategies have been developed to overcome this issue, which are summarized in detail. Last, future research directions for the CaL-CLC process are proposed.