separation of mixture isopropanol-water 1

[smartiron]

Hi all,

could anybody help me with a problem? i need to separate a mixture containing 40 mol% isopropanol and 60 mol% water, a purity at least of 99 mol% is desired for both . They say, it is useful to use solvent such as phenol or benzene, however, i cannot separate them.. And does anybody know something about Salt-effect distillation to separate my mixture?

Thanks a lot for all the answers.

 

[chemicalengineerthai]

You can use alternative way by liquid membrane( pre separation to 8o% purity) to reduce huge load of distillation.

 

[BenjaminM]

Distillation is one option. I'm guessing your solution will azeotrope around 96% or so. You'll have to look at pressure distillation to get pass the azeotrope.

I do not know if a desicant material would work for seperating the water. I doubt it would be economical on the large scale.

What physically happens when an alcohol/water solution freezes? Does the alcohol seperate? I doubt that is really good solution either.

Several million dollars worth of centrifuges might do it?

As for the effects of salt distillation, do you mean adding salt to the solution? If so, the temperature in your sump will be slightly higher than that of pure water. Say 103-105*C or so. Your vapor temperature shouldn't increase past 100*C so long as you are not under pressure.

Sorry I can't do more than offer a few brain storm ideas that probably wouldn't work anyway.

 

[smartiron]

Yes, Im going to use a distillation. A solution of isopropanol-water is azeotrope, from Aspen Properties I know, the min boiling point is 80.2°C and a mol fraction of isopropanol for this point is 0.675. What I can do (I guess) is to separate pure water from the azeotrope which will consists of 0.675 mol% of isopropanol and 0.325mol% of water. Then, I want to use an azeotropic distillation.. And this the problem.

Which solvent is useful? And what pressure?

It is written to use benzene for separation in Separation Process Principles by Seader. So, I try this and will see what will happen.

thanks..

 

[StoneCold]

If this process is big enought to use distillation then I would really consider using two columns and run them at different pressures to get past the azeotrope. That would be better than adding a third component.

Regards

StoneCold

 

[PISA]

Smartiron,

This is a typival application for an hybrid system:

Distillation up to 80% Isopropanol

+ Vapour permeation (isothermal pervaporation in a vapour phase) from 80 to 99.5%

Suppliers in membrane-guide.com:

http://www.membrane-guide.com/membrane_separation/pervaporation/pervaporation_europe.htm

Hope it helps,

Anne

 

[semsagro]

You can use cyclohexane

 

[smartiron]

Thanks all,

but I need to separate these components with distillation.. Cyclohexane or benzene can help to form two liquid phases and they say, this is the way how to separate them from each other. But I still have a problem to design a column with decanter in HYSYS for my separation.. Does anybody know any tutorial to design an azeotropic distillation with decanter? Or something else? Thanks!