Residue Curve Bundles of Four-Component Mixtures

Residue Curve Bundles of Four-Component Mixtures 

The structure of residue curve bundles of four-component mixtures is significantly more complex and diverse than that of three-component mixtures. This is due to the fact that each four-component mixture consists of four three-component constituents. Therefore, the number of types of four-component mixtures is enormous. In addition to that, four-component mixtures can have four-component node and saddle azeotropes. In contrast to three-component mixtures, the enormous 

The totality of all bonds characterizes the mixture s structure. The bond serves as the elementary nonlocal characteristic of the residue curve bundle structure. Bonds form bond chains. The bond chains of maximum length connect the unstable node A and the stable node A+ of the distillation region Reg . Let s call a polyhedron formed by aU stationary points of one maximum-length bond chain and containing aU components of the mixture a distillation subregion Reg.  

The distillation region Reg°° is a polyhedron formed by all stationary points of the totality of aU maximum-length bond chains connecting the same unstable node of the composition space with the same stable node (it will be designated ). The examples of distillation regions Reg° are 12 4, 12 = 2 (at Fig. 1.7a), 

As we will see in Chapter 3, the distillation region and subregion characterize those possible product compositions that can be produced from the given feedstock composition by distillation under one of the most important modes, in particular, under the infinite reflux mode. 

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