11 replies to this topic

[jhonny]

please can anyone help me in selecting the heavier component to do the distillation of acetone aniline and water

 

[thorium90]

Why would you need people to decide which is the heavier component when gravity can decide that for you? Perhaps what you need are ternary diagrams.

Edited by thorium90, 24 February 2013 - 10:46 AM.

[jhonny]

i mean to say is that which component should i decide as the bottom product for the distillation column. as in i need to design  such a column where i get acetone as my top product and water and aniline at the  the bottom. top is fixed it has to be acetone . but at the bottom i am having problems while designing the bottom part.

[thorium90]

Perhaps looking at this curve will give you a better idea how to do it

Attached Files

•  azeo.jpg   83.86KB   38 downloads
•  ternary.jpg   86.12KB   38 downloads

Edited by thorium90, 25 February 2013 - 04:43 AM.

[jhonny]

thanxx a lot thorium.

i tried simulating the column but i could not since i am not able to decide the pressure and temprarure

at the bottom for aniline and water. so according to the data sent by u shud it be the azeotropic pressure??

[thorium90]

The likely range of pressures to use can sometimes be limited by the units upstream and downstream of the process. The temperature is therefore a consequence of the pressures selected. The azeotrope occurs at the pressure I simulated it at (1atm), at that composition and temperature. Perhaps reading the following link might help you understand the meaning of azeotrope

 

http://en.wikipedia....ic_distillation

Edited by thorium90, 25 February 2013 - 10:32 AM.

[jhonny]

okkay but then since it wil boil at 1 atm i will have to give the feed to the column at a lower

pressure right???

[jhonny]

actually i need the upper temprature to be 56 and that of the bottom to be 98 which is the boiling point for the azeotropic aniline water mixture. i am getting the upper one how can i do the bottom one??

Edited by jhonny, 25 February 2013 - 10:50 AM.

[thorium90]

Anything can possibly boil at any temperature depending on the pressure it is at. When the pressure increases, the boiling temperature increases. In this case, it is a mixture, so the composition also plays a part. The higher the fraction of higher boiling point component, the higher the starting point where it boils.

 

What do you mean by you are getting the upper one?

 

To be frank, your understanding of distillation concepts, chemical engineering concepts is very lacking. You might want to dig out your lecture notes and textbooks to revise.

[jhonny]

okkay thanxx

[jhonny]

can u give me some data on aniline water azeotrope?

[thorium90]

I thought post 4 was pretty detailed already? Its got the pressure, temperature and composition.. Unless, you need at different pressures, for which you would need a PT diagram. You can use the same fluid package to generate the PT envelope. UNIQUAC/RK seems suitable and it managed to detect azeotrope locations too.

Edited by thorium90, 26 February 2013 - 10:41 PM.