混合物立方型状态方程的统计力学分析及混合法则的改进

STATISTICAL MECHANICAL ANALYSIS OF CUBIC EQUATION OF STATE FOR MIXTURES AND IMPROVEMENT OF MIXING RULE

一、前言 众所周知,使用立方型状态方程和通常的混合法则计算含相似组分的混合物其结果是比较满意的。但对非相似组分的混合物计算误差较大。最近的一些研究表明,如果在计算非相似组分的混合物时,若改进通常的混合法则,可使计算精度明显提高。本文的目的是从混合物立方型状态方程的统计力学分析和非相似组分分子之间存在的相互作用位能分析出发,对通常的混合法则作了改进。文中并以PR状态方程为例,结合改进的混合法则对非相似组分二元混合物作了算例,得到的结果是令人满意的。

This work presents an improvement for the most commonly used mixing rule from analysing the cubic equation of state according to the method of statistical mechanics and the inter-molecular potential energy between the fluid's molecules. The vapor-liquid phase equilibrium are calculated for 18 binary mixtures using the improved mixing rule and the Peng-Rubinson equation of state. The results agree well with the published data.