光热发电技术通过配置储热系统，可将不稳定的太阳能供给转化为稳定的电力输出，对电网更加友好。热化学储热技术具有工作温度高、储能密度大的优势，在高温储热领域应用潜力较大。关于储热介质气固反应动力学的研究是热化学储热反应器设计和运行优化的基础。本文围绕热化学储热气固反应机理，从晶粒-颗粒-反应器多尺度层面开展动力学理论模型研究，并应用多尺度模型分析了实验测得的典型热化学储热介质的反应动力学特性。在表面反应机理方面，根据反应过程中介尺度固体产物结构生长特性，模型中提出采用分散的产物岛生长模式代替传统模型中关于连续均匀产物层的假设，基于固体产物单体的表面扩散-捕获模式建立了产物岛生长理论，通过引入参数表面裸露份额建立了介尺度反应动力学机理模型，分析了模型中关键参数对反应进程的影响机制，模型可准确解释实际过程中反应动力学从快速阶段向产物层扩散阶段转折现象的本质机理。在介尺度反应机理模型基础上进一步考虑了颗粒孔隙内气体传质行为对介尺度反应进程的影响，建立了基于产物岛生长理论的颗粒尺度反应动力学模型，探讨了颗粒结构控制机制，并基于蒂勒模数法建立了解析解形式的颗粒尺度模型快速求解算法，提高了计算效率。将基于快速求解算法的单颗粒模型嵌入反应器尺度模型中，建立了晶粒-颗粒-反应器多尺度动力学分析方法，揭示了微观产物结构生长与宏观储热介质动力学特性的跨尺度关联。应用多尺度模型分析了通过微型流化床热重分析方法实验测得的热化学储热介质反应动力学特性，包括CaO/CaCO3和CoO/Co3O4体系。结果表明，高温下CaO碳酸化反应的临界转化率为~0.6，其反应过程中易发生颗粒孔隙堵塞现象，50% CO2时热量释放速率极大值点对应的温度为~750 °C；而CoO氧化反应的临界转化率接近于1，该反应中固体产物生长对颗粒孔隙尺寸影响较小，21% O2时热量释放速率极大值点在700~750 °C之间。基于多尺度模型探究了表观实验现象背后的跨尺度气固反应步骤，讨论了粒径对动力学影响的三区域特征，其中当CaO粒径小于~90 μm时，碳酸化反应进程由化学反应步骤控制。通过分析颗粒结构变化特征和反应控制步骤，进而提出了储热介质反应性能改进策略。

By configuring thermal energy storage system in concentrating solar power (CSP), unstable solar energy can be converted into stale power output, which is friendly to the grid. Thermochemical heat storage (THS) technology has the advantages of high operation temperature and high energy storage density. Therefore, THS has good application potential in the field of high temperature heat storage techology. Gas-solid reaction kinetics is the basis for the design and operation of thermochemical heat storage reactor. In this study, the gas-solid kinetic mechanism in THS technology was investigated from the multi-scale model aspect, including grain, particle and reactor scales, and the multi-scale model was applied to analyze the experimentally measured kinetic characteristics of typical thermochemical heat storage media.In terms of the surface reaction mechanism, based on the structure characteristics of the mesoscale product during the reaction process, a dispersed solid product island growth mode was proposed in the model to replace the assumption of continuous uniform product layer used in traditional gas-solid models. Based on the surface diffusion-capture process of the solid product monomers during the reaction, the solid product island growth theory was established, and the mesoscale reaction mechanism model was developed by introducing the parameter of the fraction of unoccupied reactant surface. The influence mechanism of key parameters in the model on the reaction process was analyzed. The model can accurately explain the essential mechanism for the transition phenomenon of reaction kinetics from initial fast stage to slower product layer diffusion stage.On the basis of the mesoscale reaction mechanism model, the influence of the gas diffusion behavior through the particle pores on the mesoscale reaction process was further considered, and the particle-scale kinetic model based on the product island growth theory was established. The controlling mechanism of the particle structure was discussed. A fast solving algorithm of the particle-scale model in the analytical solution form was established using the Thiele modulus method. The particle-scale model based on the fast solving algorithm was embedded into the reactor-scale model, and the grain-particle-reactor multi-scale kinetic analysis method was established, revealing the cross-scale correlation between the micro product structure growth and the macro kinetic characteristics of the heat storage medium.The multi-scale model was applied to analyze the kinetic characteristics of the thermochemical heat storage medium measured using the microfluidized bed thermogravimetric analysis method in the experiment, including the CaO/CaCO3 and CoO/Co3O4 reaction systems. The results showed that the critical conversion of CaO carbonation reaction at high temperature achieved ~0.6, and pore plugging phenomenon on the particle surface was prone to occurrence during the CaO carbonation reaction. The temperature corresponding to the maximum heat release rate at 50% CO2 was ~750 °C. The critical conversion of CoO oxidation reaction was close to 1, and the growth of solid products during the CoO oxidation reaction had little effect on the particle pore size. The temperature corresponding to the maximum heat release rate at 21% O2 was between 700 and 750 °C. Based on the multi-scale model, the cross-scale gas-solid reaction steps behind the apparent experimental phenomena were explored, and the three-region characteristics of the impact of particle size on the reaction kinetics were discussed. When the particle size of CaO was less than ~90 μm, the carbonation reaction process was determined by the chemical reaction step. By analyzing the characteristics of particle structure and reaction control steps during the reaction process, a strategy for improving the reaction performance of heat storage medium was proposed.