A NEW EQUATION OF STATE-BASED ON NONRANDOM 2-FLUID LATTICE THEORY FORCOMPLEX-MIXTURES

A new simplified equation of state (EOS) was derived based on the nonr andom lattice fluid model with the introduction of the two-fluid theor y. Admittedly the new EOS was originated from the density dependent co mbinatory and has features similar to the UNIQUAC model. However, it r esults in volumetric EOS instead of excess Gibbs energy model. The new EOS was tested for its capacity to represent the phase equilibrium be haviors of pure components and mixtures. The model was applied to dens ity, equilibria of vapor-liquid and vapor-solid phases for nonpolar/no npolar, nonpolar/polar, and polar/polar binary mixtures of simple and complex molecules. The simplified EOS was successfully applied to the activities of solvents in polymer solutions. With two parameters for p ure components and one binary interaction energy parameter, results ob tained to date demonstrate that the model is quantitatively applicable to a wide range of temperatures, pressures and densities.