Sharp Extractive Distillation of Three-Component Mixtures

Sharp Extractive Distillation of Three-Component Mixtures 

In contrast to columns with two feeds examined in the previous section for which composition and amount of each feed flow were set, only the main feed (i.e., the mixture under separation F) is set in columns of extractive distillation. The amount 

This allows us to actively influence the location of the pseudoproduct point of the intermediate section in order to maintain sharp separation (i.e., separation at which the intermediate section trajectory ends at some boundary element of the concentration simplex). This is feasible in the case when inside concentration simplex there is one trajectory of reversible distillation for pseudoproduct point x ) that ends at mentioned boundary element, and there is the second trajectory inside this boundary element. To maintain these conditions, pseudoproduct point x j) of the intermediate section should be located at the continuation of the mentioned boundary element, because only in this case can liquid-vapor tie-hues in points of reversible distillation trajectory located in this boundary element he at the lines passing through the pseudoproduct point x jy. We discuss these conditions in Chapter 4. It was shown that in reversible distillation trajectory tear-off point x[ev e from the boundary element the component absent in it should be intermediate at the value of the phase equUibrium coefficient between the components of the top product and of the entrainer rev,D Kevj Kev.s)- This condition is the structural condition of reversible distillation trajectory tear-off for the intermediate section. Mode condition of tear-off as for other kinds of sections consists of the fact that in tear-off point the value of the parameter (LfV) should be equal to the value of phase equilibrium coefficient of the component absent at the boundary element in tear-off point of reversible distillation trajectory ((L/V)m = 

At sharp adiabatic distillation in the intermediate section, several components may be absent at the pseudoproduct boundary element at which section trajectory ends, and the structural conditions of reversible distillation trajectory tear-off into all the adjacent boundary elements having dimensionality bigger by one should be valid in the trajectory tear-off point x[ from the boundary element  

The condition (LIV) (mode condition of section trajectory tear- 

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