Continuous column design help

[lost_sense]

i need ur help i am new bee about aspen hysys

and i have a problem about this program maybe anybody can help me

i want to design a continuous distillation column and

my feed containing 292 kg acetonitrile
0,3 kg water
0,025 kg aceton
5,38 kg propionitrile
0,6 kg cis crotonitrile

i think that feed temperature 74 C or close it i wanna take all acetone from top
and also i wanna take nearly all acetonitrile as side stream.


i want ur help please help me

[leon_aurel]

could you be more specific about your problem?? i mean what is it exactly the problems you have..

[superandy]

Dear lost_sense,

I don't believe you can obtain the requested separation: liquid acetonitrile drawn from a tray (I guess a top tray) and acetone as vent in a partial condenser.

Probably you have to use two serial distillation.

The first one to remove as liquid at the top a mix with acetonitrile and acetone containing some impurities with a 99.9% of acetonitrile recovery.

The second one to split acetonitrile from acetone.

Let me know...

Regards
superandy

[lost_sense]

actually i did simulation but there are something which are not normal.

i wanna describe it to you

feed is aded from 1. stage @ 74 C ( stage number increasing top to bottom ). in here i think that acetone is vapor( boiling point nearly 56 C ) and i must goes up and it can be obtained from top .
and i wanna take acetonitrile as vapor from 6 stage as a side stream. boiling point is about 77 C.

and propionitrile and cis crotonitrile have boiling points repectively 97 C , 120 C.

so we dont have a chance to obtain these both propionitrile and cis crotonitrile from top i can take them from bottom.


but accoding to my simulation results i found nearly 3 kg crotonitrile in side stream.
and nearly no aceton is obtained from top.


there must be a wrong thing !

i didnt find it


pls help me maybe u can give me any good idea


and also how can i learn optimum column size? i dont know it too

thx all of u

Alper