Abstract:

Calcium looping technology is widely regarded as a thermal chemical energy storage technology with great development potential due to its high thermal storage density, low cost of raw materials, and environmental friendliness. However, traditional modeling techniques have shortcomings in heat and mass transfer as well as mechanical stability of the porous structure, which limit the promotion and application of calcium looping technology. This study innovatively proposes a hierarchically porous structure modeling strategy, successfully preparing a CaO-based thermal energy storage module with a hierarchically porous structure, good cycling stability, and strong mechanical properties through the combination of foaming technology and template sacrifice method, as well as the introduction of polyvinyl pyrrolidone as a binder. Experimental results show that the thermal energy storage module has a large-span porous structure ranging from 60 nanometers to 1.2 millimeters and achieves the integration of material and structure design. The self-supporting structure formed avoids the issue of reduced energy storage density caused by the introduction of inert support bodies. After 100 cycles of stability and compressive strength testing, the thermal energy storage module maintained its structural integrity, with an energy storage density of 1094 kJ/kg and a compressive strength of 0.31 MPa. Moreover, the synthesis strategy of the thermal energy storage module proposed in this paper has a simple process flow, avoiding cumbersome steps and dependence on high-cost equipment, meeting the needs of industrial large-scale production. This study provides a new perspective and solution for the application of calcium looping technology in the field of thermal chemical energy storage, and is expected to promote further development and commercialization of calcium looping technology.

Key words: thermochemical heat storage, calcium oxide, modular molding, hierarchically porous structure