Correlation and prediction of vapor-liquid equilibria

The definition of technical words “correlation” and “prediction” in the vapor-liquid equilibrium (VLE) calculation have been considered. “Correlation” should be used when VLE is calculated by using the experimental VLE data of a mixture concerned. Namely, this means the evaluation of the model parameters of an activity coefficient equation from experimental VLE data. On the other hand, “prediction” is acceptable when VLE can be obtained by calculation, with no VLE data of a mixture concerned, based on the knowledge of molecular structures and the pure component properties of constituent pure components. As a useful prediction method, UNIFAC has been widely adopted. The performances of UNIFAC and GC-W proposed by the present study are compared and discussed in the prediction of VLE for various binary mixtures consisting of non-polar and polar components.

vapor-liquid equilibrium

correlation

prediction

Wilson equation

group-contribution method

pure-component property

UNIFAC