A strategy for drawing mole fraction curve maps for heterogeneous mixtures, using the nonequilibrium model that involves rigorous mass-transfer calculations, is presented. The calculations involve the use of rigorous stability analysis in the form of the Gibbs tangent plane criterion and nonequilibrium liquid-liquid calculations when the mixture is determined to be unstable. This is followed by a nonequilibrium bubble-point calculation. A comparison of the equilibrium and nonequilibrium mole fraction curve maps for the mixture of ethanol, benzene, and water is presented.