Calculations of multicomponent phase equilibria with a new group contribution method

Abstract

The present paper introduces a new group contribution model (GTASQUAC) for calculations of multicomponent phase equilibria of organic compounds. The method is based on the concept of quasi-chemical equilibrium using the TASQUAC formalism for determination of contact numbers in the liquid mixture. GTASQUAC has two adjustable parameters for describing the temperature dependent interchange energy and was applied to the description of VLE and heat of mixing data. The results are compared to those of other "‘local composition models'' like UNIFAC, ASOG or mod. UNIFAC using two, four or six adjustable parameters, respectively. GTASQUAC can also be applied for true prediction of thermodynamic excess properties. A comparison with simulated heat of mixing data shows good agreement. Moreover, the method provides a high flexibility.