The investigation of multicomponent liquid mixtures is an exhaustively investigated area of the engineering sciences. The distillation based separation of ideal or almost ideal mixtures has been comprehensively studied. Also several design/synthesis strategies have been recommended by several authors. The separation of the non-ideal mixtures is a newer area of the engineering sciences but several significant contributions have been done up till now. In spite of the several hundreds of publications and books about the separation of the non-ideal mixtures, the topic is still not exhausted and new problems and areas are arising day by day. It is difficult to give general classification like in the case of the ideal mixtures because the vapour-liquid-liquid equilibrium of the non-ideal mixtures is usually quite complex and unique. Therefore, the vapour-liquid-liquid equilibrium is investigated in this work and on the behalf of this investigation separation solutions are developed which can be successfully applied for the separation of non-ideal mixtures. The importance of this research work can be also explained with the significant industrial needs for the efficient solution of solvent recovery problems. Since the waste streams of the solvent mixtures arise usually in quantities of around several thousand tonnes per year, continuous recovery methods are considered.