Solar and other renewable energy driven gas-solid thermochemical energy storage (TCES) technology is a promising solution for the next generation energy storage systems due to its high operating temperature, efficient energy conversion, ultra-long storage duration, and potential high energy density. Experimental and theoretical studies suggest that the respective gravimetric and volumetric TCES energy storage densities vary from 200 to 3000 kJ kg and 1–3 GJ m. Solar radiation or heat generated from electric furnaces powered by renewable electricity can be stored in the form of chemical energy through endothermic reactions, while the stored chemical energy can be converted to thermal energy via an exothermic reaction when needed. The design of highly effective reactors requires a deep understanding of materials, thermodynamics, chemical kinetics, and transport phenomena. At time of writing, TCES reactors are yet to be deployed at commercially relevant scales, leaving a substantial gap between development efforts and commercial feasibility. Therefore, this review aims to examine the state-of-the-art design and performance of particle-based TCES reactors with different reactive materials. Fundamentals related to TCES reactive materials, reaction conditions, thermodynamics and kinetics, and transport phenomena are reviewed in detail to provide a comprehensive understanding of the reactor design and operation. Five major types of TCES reactors have been comprehensively reviewed and compared, including fixed, moving, rotary, fluidized, and entrained bed reactors. Most reported prototype reactors in the literature operate at lab scale with thermal inputs below 40 kW, and scaled TCES reactors (e.g., at megawatt level) are yet to be demonstrated. The nominal reactor operating temperatures range from 300 to 1500 °C, depending on the selected chemistry, reactive material, and heat sources. To evaluate their designs, the reactors are assessed in aspects of performance, cost, and durability. Discrepancies in performance indicators of energy storage density, extent of reaction, and various energy efficiencies are highlighted. The scale-up of reactors and power block integration, which hold the key to the successful commercialization of TCES systems, are critically analyzed. Advanced materials (both reactive materials and ceramic reactor housing materials), effective particle flow control, advanced modeling tools, and novel system design may bring significant improvement to the energy efficiency, storage density and cost competitiveness of particle-based TCES reactors.

中文翻译：

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颗粒高温热化学储能反应堆

太阳能和其他可再生能源驱动的气固热化学储能（TCES）技术因其工作温度高、能量转换高效、超长存储时间和潜在的高能量密度而成为下一代储能系统的有前途的解决方案。实验和理论研究表明，TCES 的重量和体积储能密度分别为 200 至 3000 kJ kg 和 1-3 GJ m 。太阳辐射或由可再生电力供电的电炉产生的热量可以通过吸热反应以化学能的形式储存，而储存的化学能可以在需要时通过放热反应转化为热能。高效反应器的设计需要对材料、热力学、化学动力学和传输现象有深入的了解。截至撰写本文时，TCES 反应堆尚未以商业相关规模部署，因此开发工作和商业可行性之间存在巨大差距。因此，本次综述旨在研究采用不同反应材料的基于颗粒的 TCES 反应器的最先进设计和性能。详细回顾了与 TCES 反应材料、反应条件、热力学和动力学以及传输现象相关的基础知识，以提供对反应器设计和操作的全面了解。对TCES反应器的五种主要类型进行了全面的回顾和比较，包括固定式、移动式、旋转式、流化床式和气流床式反应器。文献中报道的大多数原型反应堆均在实验室规模运行，热输入低于40 kW，而规模化的TCES反应堆（例如兆瓦级）尚未得到论证。标称反应器工作温度范围为 300 至 1500 °C，具体取决于所选的化学物质、反应材料和热源。为了评估其设计，我们对反应堆的性能、成本和耐用性进行了评估。强调了能量存储密度、反应程度和各种能源效率等性能指标的差异。对反应堆的放大和功率块集成进行了批判性分析，这是 TCES 系统成功商业化的关键。先进材料（反应材料和陶瓷反应器外壳材料）、有效的颗粒流控制、先进的建模工具和新颖的系统设计可能会显着提高基于颗粒的TCES反应器的能源效率、存储密度和成本竞争力。