Liquid-Liquid Equilibrium Calculations with Two-Suffix Margules Model using Genetic Algorithm for Ternary Systems Containing Aromatic, Aliphatic and Ionic Liquid Components

The stochastic global optimization methods have been extensively used in fluid phase equilibrium calculations. Among these methods, Genetic Algorithm (GA) has been applied here to calculate the parameters of Two-Suffix Margules activity coefficient model for ionic liquid based systems. This model is nonlinear with several local extrema. GA leads to globally optimum values; it does not require any initial guess and only the lower and upper bounds of the parameters as variables are required. In the present work, based on the GA method, the parameters of this activity coefficient model have been calculated for 20 different extraction systems including 20 different ionic liquids. Values of the parameters along with the root mean square deviations (rmsd) are reported. The obtained results, in terms of rmsd for this model are satisfactory, with the global value of 0.02341 for 172 tie-lines. The rmsd results show that this model can correlate the experimental data of ternary extraction systems containing ionic liquids. It is shown that Two-Suffix Margules activity coefficient model can be applied successfully in ternary liquid extraction systems calculations containing ionic liquids.

Keywords:

Genetic Algorithm , Two-Suffix Margules Model , Parameter Estimation , Liquid Liquid Equilibrium , Ionic Liquid