Splitting of CO2 via the Heterogeneous Oxidation of Zinc Powder in Thermochemical Cycles

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• 作者：Yanwei Zhang ; Tingting Nie ; Zhihua Wang ; Jianzhong Liu ; Junhu Zhou ; Kefa Cen
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2016
• 出版时间：January 27, 2016
• 年：2016
• 卷：55
• 期：3
• 页码：534-542
• 全文大小：613K
• ISSN：1520-5045

文摘

This study focuses on the mechanism that governs the CO₂-induced oxidation of Zn powder in a dropping state via a one-dimensional drop-tube furnace system. Parameters including temperature, CO₂ concentration, residence time, and particle size were considered. Results showed that the oxidation of Zn powder with CO₂ can be divided into three periods according to reaction temperature. Based on the oxidation of spherical Zn particles in the dropping state at a representative temperature for each period, the reaction mechanism was characterized by a shell–core model with three temperature regimes. Meanwhile, equations for the reaction rates were formulated using nonlinear regression analysis. This model is consistent with scanning electron microscopy and transmission electron microscopy results. In addition, the theory of anion coordination polyhedron growth units for crystals was applied to explain the nucleation, growth, and final morphology of ZnO crystals.