# Multicomponent Simple Batch Distillation

Multicomponent Simple Batch Distillation

Consider three components , , and having the following relative volatilities and computed relative to .

A

B

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α

21

α

23

B

The heaviest component is component , the lightest component is , and is the intermediate boiling component. Thus we have <1 and >1.

C

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B

α

21

α

23

A batch still is charged with a 120 kmol mixture containing 20% , 30% and 50% . The distillation removal rate is assumed constant and equal to 1 kmol/hr. The Demonstration computes the composition of the liquid remaining in the still as well as the composition of the distillate and plots the mole fractions of component , , and in the distillate (yellow, magenta and blue curves, respectively). The four snapshots correspond to various selections of and . We observe perfect separation between the three components when <<1 and >>1. Indeed, components , , and exit the column separately and successively (i.e., following the order of volatility), while when and are both close to unity, there is almost no separation and the three components exit the still together.

A

B

C

A

B

C

α

21

α

23

α

21

α

23

A

B

C

α

21

α

23