9 replies to this topic

[kuldeep singh]

Dear Sir

I have given a task to design a batch distillation packed column in which there are three components. i already designed a continous column but dont have any idea of designing a batch column, is that i have to design a column by using Rayleigh equation and Gilliland correlation.
The main problem in designing the batch distillation is that its composition changes with time.
So can you help me how to design a batch multicomponent packed distillation column.

Regards
Kuldeep

[S.R.Shah]

Kuldeep;

As you have already designed continuous Distillation column ;Batch distillation is also possible.

In your case feed mixture comprises total three components .

For Batch distillation ,depending on coolant available ,apply suitable vacuum(Absolute pressure ) to boiling point of Highest volatile solvent(From vapor pressure data) to remove .

For other Components different higher vaccum shall be needed.

Condnesate may have purity needed or not .Second purification column may also needed.

One may need different coolant temperature depending on solvents .

Above is generalised procedure .One has to take due care depending on Solvent mixture and its vapor pressure and boiling points.

If you have assignment to large batch distillation column ,Pilot plant trials shall help you lot for defining Operating pressure,temperature
column diameter and height and different packings.

SRShah

[breizh]

Kuldeep ,
May be interesting to read :
http://uguryildiz.co...siv/res/MSc.pdf


An other resource :
Batch distillation and Operation by I.M Mujtaba , Imperial college Press

Breizh

Edited by breizh, 07 December 2012 - 02:19 AM.

[kuldeep singh]

thanks shah sir and breizh sir

actually the problem is that i have a feed mixture of 5 components. i have to take out the the most volatile first, the main problem is that the feed composition varies with time so i am not getting a proper idea of designing, should i start with the rayleigh equation, or some other method are there. sir designing a continous colun is easy as feed compositions are fixed, but for batch column i am not getting the proper idea from where i have to start.

Regards
Kuldeep

[Art Montemayor]

Kuldeep:

As demonstrated by the response, you have attracted the attention of two, good, experienced, and knowledgeable professional engineers. As I previously noted to you, this is what you can expect from this Forum: good, serious, and expert help. However, I also advised you to furnish ALL your accurate and completed basic data - including as many sketches, or drawings as you can in order to facilitate our members in helping you.

Now, you have changed your basic data from a 5-component feed to a 3. SR Shah'a response and Briezh's is based on what you furnish. If you furnish wrong or varying basic data, the help you receive will be wrong, confused, or simply not be there at all. It is your responsibility to organize your submitted data as I indicated. The more accurate and organized you are, the better the response.

For example, you should at least state and quantify the actual feed composition you are proposing, as well as all other specific data. Are you using a water-cooled overhead condenser? Or an air-cooled one? Are there any gases or non-condensables in the feed? Are all the components totally miscible? Etc., etc., etc. Give all the specific information.

We professionals on the Forum know precisely what is involved in a batch distillation. You don't have to explain the method or the theory, as well as the problem of time-related compositions. We know that. Concentrate on giving ALL of your information - and that includes your own, personal work product and calculations on this problem, in an Excel spreadsheet so that we can gauge if you are doing it correctly and logically. That way, you get FREE calculation checking - and from experts! However, if you have done NO EFFORT OR WORK on your own problem, do not expect or look forward to our members doing your work for you. We are not a homework furnishing Forum. So, submit your work effort up to now and show where you are stuck and need help.

[kuldeep singh]

Thanks sir.

The real problem is:

1. i have a feed composition of

a) tri-chloro benzene(50%), - most volatile;

b) 3-chloro 6-trichloro methyl pyridine(11%);

c) 2-chloro 6-trichloro methyl pyridine(32%);

d) 3-chloro 2-trichloro methyl pyridine(6%);

e) and residue (which is left in the kettle and is the least volatile).

2. the vacuum in the reactor is 730 mmHg and normal boiling points are 214 oC, 253.11 oC, 271 oC, and 277.25 oC.
3. taking out the solvent (trichloro benzene) first, my main product is 2-chloro 6-trichloro methyl pyridine.
4. The capacity of the reactor is 13 Kl.

My problem is i have to design a batch distillation packed column for this feed composition.

i tried it by using a continous column and i am attaching the excel sheet for variable composition.

Regads
Kuldeep

Attached Files

•  designing of multi component distt .xlsx   13.36KB   181 downloads

Edited by Art Montemayor, 08 December 2012 - 08:44 AM.
readability; composition

[kuldeep singh]

Dear Sir

i calculated all the normal boiling points by GROUP CONTRIBUTION METHOD.

Regards
Kuldeep

[breizh]

Let you find some text book , I've attached a reference where you can find detailed calculations for multicomponent distillation , including Short Cut methods :

Separation process principles by J.D Seader and Ernest J Henley ( JohnWilley&Sons, Inc)

Breizh

[kuldeep singh]

Thanks for your support. i'll try by going through the texts which you have sent

Regards
Kuldeep

[kuldeep singh]

Dear Sir

Please do something in my excel sheet. I am not getting the proper way of designing.

Regards
Kuldeep