超临界CO2中甲醇和乙醇无限稀释扩散系数的分子动力学模拟与实验测定

采用分子动力学模拟(MD)方法对甲醇和乙醇在超临界二氧化碳中的无限稀释扩散系数进行了模拟计算, 并应用泰勒分散理论, 采用超临界色谱仪对模拟结果进行了实验验证. 模拟计算值与实验值较吻合, 且变化规律基本一致, 表明采用这种新方法可以准确有效地预测超临界体系的扩散性质, 能够方便地应用于工程设计.

Molecular Dynamics Simulation and Experiment Measurement of Infinite Dilute Diffusion Coefficients of Methanol and Ethanol in Supercritical CO2

A new approach to represent the infinite dilute diffusion coefficients of organic compounds in supercritical carbon dioxide was proposed. The infinite dilute diffusion coefficients of methanol and ethanol in supercritical CO2 were investigated by molecular dynamics(MD) simulation. In order to compare the simulation results, according to Taylor dispersion principles, the infinite dilute coefficients of methanol and ethanol were determined by Supercritical Chromatography. As Taylor dispersion method was easily to reach to supercritical condition, it was suit for the calculation of supercritical diffusion coefficients. In this work, the results of the MD simulation of the infinite dilute diffusion coefficients of methanol and ethanol behaved good accordance with the experiment and literature data. This new method can be used to predict the diffusion property of supercritical systems effectively and be employed for engineering design conveniently. Therefore, as an advanced research means, molecular dynamics simulation will be used more widely.