二元液体混合物扩散系数的理论计算  

Theoretical Calculation of Diffusivity in Binary Liquid Mixtures

作　　者：阎建民[1] 乐生龙[1] Krishna R 

机构地区：[1]上海交通大学化学化工学院,上海200240 [2]阿姆斯特丹大学化工系

出　　处：《高校化学工程学报》2007年第6期919-923,共5页Journal of Chemical Engineering of Chinese Universities

摘　　要：许多化工过程涉及扩散控制的质量传递,扩散系数的获取对过程工程的精确量化具有重要意义。今提出了基于局部组成的扩散系数模型,以估算Maxwell-Stefan扩散系数随浓度的变化。仅通过无限稀释下的扩散系数,以及溶液的Wilson或NRTL参数,能够预测二元混合物的扩散系数。与文献发表的实验数据比较,对15种二元组分溶液的计算结果平均误差是6.35%。结果显示,这种模型优于目前常用的Darken模型。Since the chemical reactions and separations are often limited by the diffusion process, the knowledge of diffusivity is crucial in many chemical engineering processes. The Maxwell-Stefan approach was considered in this paper, and it was assumed that the diffusive friction of species i in another species j is proportional to the local volume fraction of j. （Фji）, but not to the mole friction ofj （xj）. Based on this local composition model, a new correlation equation for the prediction of the diffusivity in binary liquid mixtures was brought forward via using the diffusivities of infinite dilution and the Wilson and NRTL parameters of the binary solution. The results of theoretical calculation were evaluated with the published experimental data, and the total average relative deviation of the predicted values with respect to experimental data is 6.35% for 15 binary systems including those containing associative component. Results indicate that this model proposed is better than the currently used Darken＇s model.

关 键 词：扩散系数 局部组成 唯象模型 MAXWELL-STEFAN方程 

分 类 号：TQ021.4[化学工程]