Separation of methanol from water 4

[mjpetrag]

Hi,

I am looking to separate a vapor mixure of methanol and water into just methanol and water, both condensed. I played around with ideas of condensing both the methanol and water into a liquid, and using a distillation column with heat added to separate the two, but I wanted to know if anyone had better ideas to doing this.

The main reason is because I want to separate the methanol, condense it, and recycle it without any water getting in.

Does anyone have experience in doing this or any ideas?



Thanks,

-Mike

 

[25362]

Visit

http://biodiesel.infopop.cc/eve/forums/a/tpc/f/719605551/m/165101214

for a short discussion on this subject.

 

[formz]

Mike,

You can use membrane technology for doing this namely pervaporation and achieve a very good purity at both sides of the membrane.

You can start by reading the attached file

I hope my answer was useful.

Best luck to your work!
formz

 

[PISA]

Mjpetrag,

Distillation as per your original idea is the best method to separate Methanol and water,

with Pervaporation we can separate, Water out of other solvents, or Methanol out of other solvents, but not water out of MeOH.

Hope it helps,

Anne

 

[formz]

PISA,

I totally disagree with you: if you have a binary mixture of water and MeOH you can effectively separate MeOH from water, much beyond the azeotropic point.

This process is used with ethanol and methanol and it is very effective for both (you can go up to 99.6% in the case of ethanol - very beyond the azeotropic point at the 96%)- see the attached file.


What you have in a membrane process is alway a feed current, a rejected current and a permeate current. If you have a binary mixture of water and methanol and you have a permeate with 99% purity you cannot have 99% of methanol in the water...

It is also less expensive than distillation because it is less energy consumptive (you don´t need a boiler, only a pump with enough head).

I hope this could help you.

formz

 

[mjpetrag]

Formz,

Do you have a supplier for the pervaporation process? Where can I get this system? I am only looking for a laboratory scale system.

-Mike

 

[formz]

Mike,

Try to check in:

http://www.pervaporation.org/

It is the greatest worldwide directory of pervaporation technology suppliers and I am pretty sure you'll find your supplier there.

Best luck for your project.

 

[Rocco8]

Formz,

There is no azeotrope in a methanol water system. This is a very simple binary distillation that is routinely performed in the biodiesel industry.

 

[BenjaminM]

mjpetrag,

We use a distillation column to recover equivalently 100% of the methanol from a 50 / 50 %wt solution. We have a purity of around 98% coming from the top of our column.

I do not have any of the exact details on me, but I will try to give you a rough idea of our system. All these are kind of, sort of, round about, estimates.

We use a packed column. Roughly 40' tall. About 18" in diameter.

We feed 6 gal a min on average I believe and recover around 3 gpm methanol. Reflux is around 3.8 gpm.

Thermosiphen reboiler consumes 1200 #/hr steam at 100 psig. Top of the column runs at 66*C. The bottoms is around 103*C (we have dissolved solids in the water).

Steel, fabrication, and programing, I believe the total cost was in the neighborhood of $250,000.

So long as our cooling / steam supplies are not inturrupted, the column runs trouble free. I truely love it.

 

[MortenA]

Lab scale? You must have some glass equipment then

Just kidding. Your local supplier of lab equipment propably have a packaged solution for solvent recovery from waste water.

Best regards

Morten

 

[POLYtech33]

separation of methanol & water is done by using a distillation column to heat up the methanil which have lower boilig point than water, when it is condensed it is recycled back to a condenser to make it a liquid and you will have ur product with high percentage of water with a less % of methanol (0.22) or something .. maybe more or less ... I've done it likewise the way u did it & I have a verey great results ..

thanx