铁基载氧体化学链燃烧还原过程的数学模型

为了研究铁基载氧体的反应特性,基于未反应缩核模型建立了移动床内铁基载氧体颗粒还原过程的一维数学模型.模型中考虑了铁基载氧体与H2、CO的多级还原反应,气体组分体积分数模拟值与实验值的平均误差为6.9%,总还原度的平均误差为11.2%.研究表明：铁基载氧体在移动床反应器内最终还原度约为23%,主要进行的反应是第一级和第二级还原反应,第一级和第二级还原度分别为95%和40%;提高反应器内温度、选择合适的载氧体粒径及气固比有助于增加反应的深度,提高合成气及铁基载氧体的利用率,载氧体粒径建议取1~2 mm.

Mathematical model of the reduction process of iron-based oxygen carriers in chemical looping combustion

To study the reaction characteristics of iron-based oxygen carriers, a one-dimensional mathematical model was developed for the reduction process of iron-based oxygen carriers in moving beds based on the unreacted shrinking core model. In this model, the multi-stage reduction between iron-based oxygen carriers and H₂/CO was considered. The average error of gas species concentration between the simulative and experimental values is 6.92%, and the average error of reduction is 11.16%. The results show that the final reduction rate of iron-based oxygen carriers is about 23%, with the main reactions including the first-stage reduction and the second-stage one, whose reduction rate is 95% and 40%, respectively. A higher reaction temperature, suitable diameter of oxygen carrier particles and suitable gas-solid ratio are helpful to improve the depth of reaction and enhance the utilization efficiency of syngas and iron-based oxygen carriers. The recommended particle diameter is 1 to 2 mm.