We report new experimental data on concentration‐dependent molecular diffusion coefficient of ethane in toluene at temperatures ranging from 21 to 125°C and pressures up to 4.14 MPa. An analytical model has also been developed for estimation of the diffusion coefficient utilizing the experimental data of the interface velocity as a result of swelling and the rate of gas dissolution in the liquid phase. It is shown that the diffusion coefficient of ethane in toluene is dependent on the initial mass fraction of the gaseous component in the liquid. In addition, the effect of concentration dependency of the molecular diffusion coefficient on diffusive mass flux is quantified. The results reveal that the assumption of a constant diffusion coefficient introduces ~10–60% error in calculation of diffusional mass transfer flux. The developed methodology finds application in estimation of the concentration‐dependent molecular diffusion coefficient of gases in liquids.

中文翻译：

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液态甲苯中气态乙烷的浓度依赖性分子扩散系数

我们报告了在21至125°C的温度和最高4.14 MPa的压力下乙烷在甲苯中的浓度依赖性分子扩散系数的新实验数据。还已经开发了一种分析模型，用于利用由于溶胀和液相中的气体溶解速率而产生的界面速度的实验数据来估计扩散系数。结果表明，乙烷在甲苯中的扩散系数取决于液体中气体成分的初始质量分数。另外，量化了分子扩散系数的浓度依赖性对扩散质量通量的影响。结果表明，恒定扩散系数的假设在扩散传质通量的计算中引入了约10-60％的误差。