The ultimate possibilities of the process of rectification separation of multicomponent mixtures depend on the features of the structure of the liquid-vapor equilibrium diagram, in particular, on the presence of internal separating surfaces on the diagram. In the present work, the regularities of structure formation of separatrix surfaces of maximum dimensionality for systems of different chemical nature are investigated. For systems with homonymous deviations, when azeotropes relative to constituents of the same constituent are nodal points, we propose an approach to determine the number of saddle-shaped azeotropes of the first and (n-2) order and, respectively, the number of internal separatrix manifolds. The proposed approach is illustrated and confirmed on the example of model systems and industrial mixtures. The expediency of using one of the types of separation (first, second, intermediate) depending on the number and structure of internal separatrix surfaces is shown. The research presented in the article is directed to the development of the fundamental theory of thermodynamics of heterogeneous systems in the part of investigation of the structures of phase diagrams and mechanisms of their formation using thermodynamic and topological analysis within the framework of the general concept of the scientific school of Dr. Leonid Antonovich Serafimov, Professor.
A.V. Frolkova (Wed,) studied this question.