3 replies to this topic

[EdoRm]

Hi all,

 

I'm studying an ethanol production plant and I'm stuck in the distillation section. In the attached file we clearly see 2 distillation columns. In the explanation there is written that in the first column (the one on the left) we have the distillate (principally light products, some ethanol, aldehydes, acetic acid...), the first side stream (starting from the top) which contains most of the ethanol and water and the second side stream which should contain principally water and traces of ethanol (0,03% volume base).

 

Now, is it possible to have such a column? There is no bottom stream!

 

In fact, when I try to model this column in ASPEN it isn't possible to have a column without a bottom stream (i.e an outlet stream on the last plate).

 

Thank for your help.

Attached Files

•  distetanolo.png   32.98KB   1 downloads

[PingPong]

Indeed, a column with a bottoms section but no bottoms product is nonsens.

 

That drawing is not readable. Where did you get that?

[Art Montemayor]

PingPong is correct.  The flow diagram furnished is not readable (or understandable) in any language.

 

For a two-column ethanol distillation flow description on an existing Italian installation, refer to the attached workbook.  This installation produces 96% wt. ethanol.  You have given any basic data that is readable so I don't know if this applies.  I have been trying to find time to interpret the Italian verbal description in the flow diagram I have started - but this is work in progress.  Sorry, but maybe this helps.

 

 Ethanol+Water Distillation Plant.xlsx   27.45KB   45 downloads

[EdoRm]

Thank you all for the answers.

 

I haven't specified that the distillation process was in a bioethanol production plant, starting with sugarcane as raw material.

 

I passed the day doing further research and I think that finally I have a solution to this problem.

 

I write it here, maybe it can help someone in the future.

 

The correct distillation section is showed in the attached figure.

 

The column A is the wine stripping column of wine. The column A1 is the wine rectification column. The column D is for concentration of second grade alcohol. The joint of these three columns is called as distillation column. The column B is the rectification column and the column B1 is the stripping column. This joint is called as rectification column where hydrated fuel ethanol is obtained. 

 

For those who are not familiar with the terms, the wine is a mixture of ethanol (~8% volume basis), water, aldehydes, acetic acid, methanol and higher alcools.

 

In the unreadable image attached to my previous post the columns A,A1 and D were "compacted" into the unique colum on the left, with no bottom stream. We may say that the person who did that flow diagram had no idea of what he was doing...

 

 

Source: Production of bioethanol and other bio-based materials from sugarcane bagasse: Integration to conventional bioethanol production process, by Marina O.S. Dias, Adriano V. Ensinasa, Silvia A. Nebra, Rubens Maciel Filho, Carlos E.V. Rossell, Maria Regina Wolf Maciel

 

 

By the way, I'm Italian so if you need help for the translations, ask me!

Attached Files

•  immagine forum.png   150.32KB   1 downloads

Edited by EdoRm, 07 March 2014 - 02:25 PM.