Multicomponent Batch Distillation Forget McCabe-Thiele, Part

3 Multicomponent Batch Distillation (Forget McCabe-Thiele, Part 2) 

The treatment so far has been limited, superficially af leasf, to binary distillation. A number of the expressions, however, have a more general character, and among them. Equation 7.26g and Equation 7.26h are particularly interesting. Their remarkable feature is ttiat they are quite independent of the phase equilibria and number of components involved or, for that matter, of the number of plates and reflux ratio ultimately employed. They are not used to design a column but serve instead to provide important initial information required at a later stage. A similar situation was encountered in Illustrahon 7.11. 

We consider a hypothetical ternary system with prescribed feed and overhead compositions, but of an otherwise unspecified nature. One of the final bottoms compositions can be fixed as well, while the remainder follow by calculation. No equilibrium data are available, but any existing ternary azeotrope is assmned known and fixes the overhead composition. 

The aim will be to calculate the fraction distilled and the percent recovery of each component using Equation 7.26g and Equation 7.26h, as well as to fill in the missing compositions. This will provide a first and important impression of what the distillation process can accomplish. 

A feed composition of = 0.6, x = 0.2, x = 0.2, is assumed, component 1 being the most volatile. Other prescribed and calculated values are summarized in Table 7.7. 

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