A Novel Lab-scale Solar Reactor for Kinetic Analysis of Non-volatile Metal Oxides Thermal Reductions

Thermal reduction of metal oxides is of primary interest within the R&D field of solar driven thermochemistry, because it is frequently involved in processes such as thermochemical cycles for hydrogen production or in thermochemical energy storage systems for solar thermal power plants. A lab-scale solar reactor has been designed to test and analyze solar-driven reduction of non-volatile metal oxides arranged in a packed bed. The test bed allows monitoring of oxygen evolution to determine the reaction rate. Experimental tests with Mn2O3, Mn3O4 and CeO2 have been carried out and the performance of each reaction has been analyzed. Total conversion is obtained for Mn2O3 reduction. However, only some zones of the Mn3O4 and CeO2 samples achieve reaction temperature. Different types of sample-holders have been used to hold the particles packed-bed, in order to enhance the conversion. The high influence of the irradiance distribution on the sample surface is demonstrated by a testMn3O4 reduction.