一、前言 液液平衡(LLE)构成能源,石油化工等领域萃取分离的基础。NRTL方程和UNIQUAC方程现已被广泛应用于关联液液平衡,以上两方程统称为活度系数法。但活度系数法在计算高压液液平衡尤其是含超临界组份的液液平衡时遇到了明显的困难。状态方程现虽已普遍用于高压汽液平衡的计算,但真正用于液液平衡计算还为数甚少。Mathias I. Introduction Liquid-liquid equilibrium (LLE) forms the basis of extraction and separation in the fields of energy, petrochemicals and the like. NRTL equation and UNIQUAC equation have now been widely used in associated liquid-liquid equilibrium. The above two equations are collectively referred to as activity coefficient method. However, the activity coefficient method encounters obvious difficulties in calculating the liquid-liquid equilibrium of high-pressure liquid, especially liquid-liquid equilibrium containing supercritical components. Although the equation of state is commonly used for the calculation of high pressure vapor-liquid equilibrium, the calculation of liquid-liquid equilibrium is very few. Mathias