Distillation Design

[workingbugs]

I have to separate a mixture of n-butanol and water. I know the common practice is two distillation columns with a decanter which I plan on doing but I was wondering what would be the best way to size my columns. Should I use something like the fenske/underwood method for equilibrium stages or go with something else. Thanks

 

[Chance17]

My memory from College is that Fenske-Underwood is an estimating tool only.
What is the price of failure by getting the wrong answer?
Personally, I would find a computer based process simulator and do a rigorous analysis.
This allows running 20-30 cases to investigate reflux ratios - feed point location - variations in feed composition, etc.
The starting point would be good physical property models.
Doesn't this mixture have an azeotrope?

 

[workingbugs]

Chance17,
Yes the fenske-underwood is only for estimating I do know that. The price of failure isn't that great considering it's just a preliminary design so I can get a rough idea of a column size in order to get pricing for economics to turn in for a grant. The mixture does have an azeotrope but it's a heterogeneous azeotrope thats why I would use a decanter in the center of the two columns.