Welte Michael, Barhoumi Rafik, Zbinden Adrian, Scheffe Jonathan R, Steinfeld Aldo
Department of Mechanical and Process Engineering, ETH Zürich , 8092 Zürich, Switzerland.
Department of Mechanical and Aerospace Engineering, University of Florida , Gainesville, Florida 32611-6250, United States.
Ind Eng Chem Res. 2016 Oct 12;55(40):10618-10625. doi: 10.1021/acs.iecr.6b02853. Epub 2016 Sep 23.
We report on the experimental demonstration of an aerosol solar reactor for the thermal reduction of ceria, as part of a thermochemical redox cycle for splitting HO and CO. The concept utilizes a cavity-receiver enclosing an array of alumina tubes, each containing a downward gravity-driven aerosol flow of ceria particles countercurrent to an inert sweep gas flow for intrinsic separation of reduced ceria and oxygen. A 2 kW lab-scale prototype with a single tube was tested under radiative fluxes approaching 4000 suns, yielding reaction extents of up to 53% of the thermodynamic equilibrium at 1919 K within residence times below 1 s. Upon thermal redox cycling, fresh primary particles of 2.44 μm mean size initially formed large agglomerates of 1000 μm mean size, then sintered into stable particles of 150 μm mean size. The reaction extent was primarily limited by heat transfer for large particles/agglomerates (mean size > 200 μm) and by the gas phase advection of product O for smaller particles.
我们报告了一种用于二氧化铈热还原的气溶胶太阳能反应器的实验演示，这是用于分解水和一氧化碳的热化学氧化还原循环的一部分。该概念采用了一个腔体接收器，其包围着一组氧化铝管，每根管子都包含一股向下重力驱动的二氧化铈颗粒气溶胶流，与惰性吹扫气流逆流，以实现还原二氧化铈和氧气的固有分离。一个带有单根管子的2千瓦实验室规模原型在接近4000个太阳辐射通量下进行了测试，在低于1秒的停留时间内，在1919K时反应程度高达热力学平衡的53%。经过热氧化还原循环后，平均尺寸为2.44μm的新鲜初级颗粒最初形成了平均尺寸为1000μm的大团聚体，然后烧结成平均尺寸为150μm的稳定颗粒。对于大颗粒/团聚体（平均尺寸>200μm），反应程度主要受传热限制；对于较小颗粒，反应程度主要受产物氧气的气相平流限制。
