Distillation Trajectory Tear-Off at Sharp Splits

Conditions of Distillation Trajectory Tear-Off at Sharp Splits 

Let s examine two constituent parts of section distillation trajectory at the example of sharp preferable split of three-component ideal mixture (Fig. 5.6a) the part located in the boundary element (the side of concentration triangle), and the part located inside concentration simplex (triangle). There is a trajectory tear-off point from the boundary element x between these two parts. 

Figine 5.6. Preferrable split of a ideal mixture at minimum reflux (a) the section trajectories, and (b) the pinches in column (shaded). Boundaries for material balances discussed in the text are indicated by dotted-dashed Hues. 

It is necessary for the distillation trajectory to be able to tear off from the boundary element that certain conditions be valid in the tear-off point.  

To obtain these conditions, let s examine material balance along the closed contour from the zone of constant concentrations to the end of the colunm and phase equilibrium in the cross-section of any zone of constant concentrations (see Fig. 5.6b)  

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