铁基氧载体与氢气的还原反应机理辨识

Reaction Mechanism Identification of Iron-Based Oxygen Carrier and Hydrogen

本文使用化学吸附仪研究Fe_2O_3/Al_2O_3氧载体与H_2的反应机理。在化学吸附仪中氧载体与H2在不同升温速率下发生程序升温还原反应(TPR),通过氢气消耗量计算氧载体转化率X,结合热力学平衡模拟辨识不同转化率区间的主导性反应;进而利用热分析动力学的积分法并结合双外推法研究各部分的反应机理。结果表明,转化率X为0～0.35时,反应可用二级化学反应速率方程来描述,机理函数为G(X)=(1-X)^(-1)-1,而在X为0 35～0 95时,反应可用成核-核生长模型来描述,机理函数表示为G(X)=[-ln(1-X)]^(3/4)。

In this paper, the mechanism of the reduction reaction between Fe203/A1203 oxygen carrier and hydrogen was studied using chenfisorption analyzer, where the temperature programmed reduction （TPR） of hydrogen and the oxygen carrier was carried out under various heating rates. The oxygen carrier conversion rate X was calculated from the consumption of hydrogen. By combining the TPR results of reduction process and the simulation results of thermodynamic equilibrium modelling, the reaction process was divided into two stages, and the main reaction in each stage was confirmed. The reaction mechanism of each stage was identified through the integration method and double extrapolated method of thermal analysis kinetics. The results revealed that the reaction can be expressed by the second order chemical reaction function G（X） = （1 X = 0 - 0.35, and by the nucleation and nuclei growth model G（X） = X）-1 - 1 in the range of ln（1 - X）]3/4 in the range of X = 0.35 - 0.95.