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液-气的平衡组成是精馏操作的理论基础,也是化工过程进行有关设计时必需的依据。例如用精馏的方法来分离溶液中各个成分,并达到所要求的纯度时,必须预先确定液-气平衡组成的相互关系,才能求出蒸馏塔的塔板数。计算液相和气相平衡组成的方法很多,基本上可以分为三类: 第一类方法是引入活度系数以表示实际溶液与理想溶液间的偏差程度;也即表示出活度系数与液相组成、温度和压力间的关系。从而通过实验数据定出对应的常数,将液-气平衡组成间的关系用数学式表达出来。这种方法可称为热力学法。第二类方法是借助于间接的实验数据,来确定所
The equilibrium composition of liquid-gas is the theoretical basis of the distillation operation, but also the necessary basis for the design of the chemical process. For example, when the individual components of a solution are separated by distillation and the desired purity is achieved, the correlation between the liquid-vapor equilibrium composition must be predetermined before the number of plates in the distillation column can be determined. There are many ways to calculate the composition of liquid and vapor balance, basically can be divided into three categories: The first method is the introduction of activity coefficient to represent the degree of deviation between the actual solution and the ideal solution; that is, the activity coefficient and the liquid phase Composition, temperature and pressure. Therefore, the corresponding constants are determined through the experimental data, and the relation between the liquid-vapor equilibrium components is expressed mathematically. This method can be called thermodynamic method. The second method is to use indirect experimental data to determine