A multi-scale modeling of Ca-based material for solar-driven calcium-looping energy storage process: From calcination reactor to energy carrier

The calcium looping (CaL) for thermochemical energy storage possesses a great potential to promote solar thermal utilization. However, the performance of CaL, especially for the Ca-based energy carrier, cannot satisfy the expectations of industrial application, requiring enhancement between multiple length scales. Hence, a model for solar-driven CaL energy storage process, coupled by three-dimensional reactor, two-dimensional light field and one-dimensional particle models, is proposed to study the multiprocess behavior on particle flow, photothermal conversion, calcination reaction, heat-mass transfer and stress response. It is found that moving-bed reactor contributes to achieving continuous calcination and reducing particle waste, while the rapid bouncing particles inhibit the performance of single particle, with up to 45.7 % reduction in conversion. Additionally, energy carrier with stable and continuous flow normally yields high energy storage efficiency and cycle stability when the conversion of outlet particle is closed to 1 and thermal stress is less than 50 MPa.