Kinetics of Mn2O3鈥揗n3O4 and Mn3O4鈥揗nO Redox Reactions Performed under Concentrated Thermal Radiative Flux

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• 作者：Elisa Alonso ; Christian Hutter ; Manuel Romero ; Aldo Steinfeld ; Jos茅 Gonzalez-Aguilar
• 刊名：Energy & Fuels
• 出版年：2013
• 出版时间：August 15, 2013
• 年：2013
• 卷：27
• 期：8
• 页码：4884-4890
• 全文大小：491K
• 年卷期：v.27,no.8(August 15, 2013)
• ISSN：1520-5029

文摘

Manganese oxide based on the thermochemical cycle for splitting water is considered using concentrated solar energy. The high-temperature endothermic step is the thermal reduction of Mn₂O₃, which proceeds at above 1835 K via two sequential chemical reactions from Mn₂O₃ to Mn₃O₄ and then to MnO. The kinetic mechanisms of both reactions are investigated by a solar-driven thermogravimeter, with reactants directly exposed to high-flux thermal irradiation. With this arrangement, the overall kinetic rate laws are derived under similar heat- and mass-transfer characteristics existing in highly concentrating solar systems, such as solar towers or parabolic dishes. The experimental results suggest a nth-order rate for the conversion of Mn₂O₃ to Mn₃O₄ and a diffusion-controlled regime for the conversion of Mn₃O₄ to MnO. Activation energies for both reduction steps are determined and compared to previous reported data.