Thermodynamic Relations for Testing Consistency of Ternary Vapor-liquid Equilibrium Data*

Vapor-liquid equilibrium relationships are important properties for practical use, such as in the design and operation of distillation equipment. In general, vapor-liquid equilibrium relations are determined experimentally, and it is a custom to test the thermodynamic consistency of the equilibrium data. Investigators1^4-15'17'19~22-24) have proposed various methods for testing thermodynamic consistency of vapor-liquid equilibrium data. However, most of the methods are used for binary vapor-liquid equilibrium data and not for ternary data. These methods could be classified into two major groups, area consistency test and point consistency test. For ternary vapor-liquid equilibrium data, several methods of area consistency test were proposed by Broughton1), Herington3), Hirose4), Yamada24) and others. Susarev et al.20) proposed a typical method of point consistency test of ternary vapor-liquid equilibrium data. In the present paper, a new method had been proposed to test the thermodynamic consistency of ternary vapor-liquid equilibrium data. This method makes it possible to check quantitatively the thermodynamic consistency of each data point for ternary systems.