载氧体介尺度结构对氧化动力学影响机制

Effect of Oxygen Carrier Mesoscale Structure on Oxidation Kinetics

针对载氧体氧化反应,采用速率方程理论晶粒模型来描述气固反应过程.模型中认为固体产物以岛状生长,并采用速率方程理论描述产物岛生长过程.以Cu基载氧体为例进行数值计算,模型计算结果与实验数据基本吻合,且模型可以成功地描述气固反应过程中的两阶段行为.采用该模型分析了载氧体介尺度结构对气固反应进程的影响机制,包括产物层扩散控制机制和孔隙堵塞控制机制,为化学链燃烧载氧体颗粒制备中的结构优化设计提供理论依据.

Aimed at the oxygen carrier in oxidation reaction,a rate-equation-theory-based grain model was used to describe the gas-solid reaction process.The assumption of island morphology of solid product was taken in the model,and the rate equation theory was used to describe the growth of product islands.A Cu-based oxygen carrier was taken as an example to conduct numerical calculations,and the calculation results basically agreed with the experimental data.In addition,the two-stage behavior in the gas-solid reaction can be described successfully using the developed model.This model was used to analyze the effect of oxygen carrier mesoscale structure on the gassolid reaction,including the product-layer-diffusion-based and pore-plugging-based controlling mechanisms,which can provide a theoretical basis for the structural optimization design in the preparation of oxygen carrier particles in chemical looping combustion.