4 replies to this topic

[Light]

Hello All

 

I have some questions pertaining to the feed stage location and the reflux and boil-up rate requirements of a distillation column. Keeping the total number of stages and the product purity as constant, what would happen to the reflux ratio and the boil-up ratio (or the condenser and reboiler duties) if the feed stage location is lowered down the column? And whatever be the effects, are they valid over the entire column no matter how much we lower the feed stage location?

How is the feed stage location decided ultimately?

Edited by Samir Khan, 17 August 2014 - 02:11 AM.

[Ali_gholamalian]

Dear Samir

First evaluate the feed zone via components in feed stream and also Heavy Key and Light Key components.

Kister books about design and operate columns are very helpful.

 

http://www.amazon.co...r/dp/0070349096

http://www.amazon.co...r/dp/007034910X

 

E-books are also available in every free e-book pages.

[breizh]

http://www.separatio...on/MainSet1.htm

 

This resource may support your query.

Hope this helps

Breizh

[Bobby Strain]

You can get distillation simulation software free. Google ChemSep.

 

Bobby

[Padmakar Katre]

Hello All

 

I have some questions pertaining to the feed stage location and the reflux and boil-up rate requirements of a distillation column. Keeping the total number of stages and the product purity as constant, what would happen to the reflux ratio and the boil-up ratio (or the condenser and reboiler duties) if the feed stage location is lowered down the column? And whatever be the effects, are they valid over the entire column no matter how much we lower the feed stage location?

How is the feed stage location decided ultimately?

Hi,

Answering your second question first, feed tray location is generally decided based on the feed temperature & composition and column tray temperature and composition profile wherever these are similar use that tray as a feed tray.

Sensitivity of feed tray location is surely there but it again depends on many factors such as product splits across columns, sensitivity by thermodynamic model used. You can check the same with a commercial simulator such as Hysys, Pro-II. You can change the feed tray location and see the effect on reboiler & condenser duty.