Abstract: Co-doped Fe₂O₃ of different orders of magnitude were prepared as oxygen carriers, the structures of which were characterized with adsorption-desorption (BET) and transmission electron microscope (TEM). Experiments under different temperatures were performed to investigate the reaction between Co-doped Fe₂O₃ and CO to understand the chemical looping combustion characteristics of these prepared oxygen carriers. The higher the doping amount, the higher the reduction conversion at the same temperature. However, with the same doping amount, increase of temperature led to increase of reduction degree, shortening the time of complete conversion of oxygen carrier. Further analysis of chemical kinetics and reaction dynamics based on TGA curve showed that the Jander equation model was suitable for the reduction of Co-doped Fe₂O₃ at 344.7-391.0℃ and 414.7-472.5℃, and the Valensi equation model was suitable for the reduction at 607.6-681.5℃, according to which the kinetic parameters including activation energy and pre-exponential factor were also calculated. The research results could provide theoretical guidance for further application of CLC technology.

Key words: adsorption, carbon dioxide, carbon monoxide, chemical-looping combustion, reaction dynamics

摘要： 制备了不同量级Co掺杂Fe₂O₃载氧体Co-Fe₂O₃，利用BET和TEM对载氧体结构进行表征。通过在不同温度下Co-Fe₂O₃与气体燃料CO的还原反应，考察Co-Fe₂O₃对CO化学链燃烧特性。结果表明，同一温度条件下，掺杂量越高，还原反应转化率越高；掺杂量不变的情况下，温度升高促使还原程度加深，缩短了载氧体完全还原转化的时间。根据TGA曲线进行了化学动力学分析，发现Co_0.2Fe还原反应过程在344.7～391.0℃和414.7～472.5℃温度范围反应动力学对应扩散控制的Jander方程模型，607.6～681.5℃温度范围对应二维扩散反应模型，并分别计算出相应模型的表观活化能和频率因子。结果可为化学链燃烧技术应用提供理论指导。

关键词: 吸附, 二氧化碳, 一氧化碳, 化学链燃烧, 反应动力学