Structural Analysis of Phase Diagram and Assessment of Possibility for Distillation of Multicomponent Mixtures

The present study explores methodologies for investigating the structure of the vapor–liquid equilibrium diagram of multicomponent systems. This investigation serves as a foundation for the predesign of distillation process flowsheets. A thorough analysis is conducted to assess the merits and limitations of existing methodologies, highlighting the efficacy of employing diverse techniques contingent on the system’s phase behavior specificity (e.g., the presence of one (two) singular points and internal separatrix manifolds). A group of systems that demonstrate the same deviations from ideality (in the absence of saddle-type ternary azeotropes) is identified. For these systems, it is possible to analyze the diagram structure based on the minimum amount of available information (i.e., boiling points of components and azeotropes). The proposed approach does not necessitate geometric construction of the concentration simplex, its scan, or individual components of the system. The proposed technique for analyzing the diagram structure of multicomponent systems is illustrated on the example of three industrial mixtures comprising different components.