Abstract A laboratory-scale solar reactor prototype dedicated to calcination processes of non-metallic mineral particles is tested and characterized. The prototype consists of an indirect heating shallow cross-flow fluidized-bed reactor-receiver. It is composed of 4 compartments in series in which the particles are thermally treated with solar power in order to drive the endothermic calcination reaction. The particles are fluidized in the reactor with preheated air and are heated up to 800 °C through the front wall of the reactor receiving the concentrated solar flux (about 200 kW/m2). The tests are carried out at the 1-MW Odeillo’s solar furnace (France). The thermal decomposition of a continuous stream of 9.4 kg/h of dolomite (CaMg(CO3)2) is investigated in this paper. The half decomposition of dolomite (CaMg(CO3)2 → CaCO3 + MgO + CO2) is performed with a degree of conversion of 100%. The complete decomposition of dolomite (CaMg(CO3)2 → CaO + MgO + 2CO2) is not reached because, with respect to the CO2 partial pressure in the reactor, the temperature of particles is not high enough to decompose the calcium carbonate. The calculated thermochemical efficiency (i.e. the energy absorbed by the endothermic calcination reaction compared to the solar energy provided to the system) is 6.6%. This low efficiency is neither surprising nor critical since the reactor design was not optimised with respect to energy efficiency but designed to the control of particle flow and front wall solar flux distribution. A numerical model considering the 4 compartments of the reactor as 4 ideal continuous stirred tank reactors in series is developed. The model accounts for the mass and the energy balances, as well as the reaction kinetics of the half decomposition of dolomite. The model gives consistent results compared to the experimental data. These results are a proof of concept of continuous calcination reaction using concentrated solar energy in a cross-flow fluidized-bed reactor.

中文翻译：

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用于连续煅烧过程的浅错流流化床太阳能反应器

摘要 测试并表征了实验室规模的太阳能反应堆原型，该原型专用于非金属矿物颗粒的煅烧过程。原型由间接加热浅错流流化床反应器接收器组成。它由 4 个串联的隔室组成，其中用太阳能对颗粒进行热处理以驱动吸热煅烧反应。颗粒在反应器中用预热空气流化，并通过反应器的前壁加热至 800 °C，接收集中的太阳能通量（约 200 kW/m2）。测试在 1 兆瓦 Odeillo 的太阳能炉（法国）中进行。本文研究了 9.4 kg/h 白云石 (CaMg(CO3)2) 连续流的热分解。白云石的半分解（CaMg(CO3)2 → CaCO3 + MgO + CO2）的转化率为 100%。未达到白云石的完全分解（CaMg(CO3)2 → CaO + MgO + 2CO2），因为相对于反应器中的 CO2 分压，颗粒的温度不足以分解碳酸钙。计算出的热化学效率（即吸热煅烧反应吸收的能量与提供给系统的太阳能相比）为 6.6%。这种低效率既不令人惊讶也不重要，因为反应器设计并未针对能量效率进行优化，而是设计用于控制粒子流和前壁太阳能通量分布。建立了将反应器的4个隔室作为4个理想的连续搅拌釜串联反应器的数值模型。该模型考虑了质量和能量平衡，以及白云石半分解的反应动力学。与实验数据相比，该模型给出了一致的结果。这些结果证明了在错流流化床反应器中使用集中太阳能进行连续煅烧反应的概念。