3 replies to this topic

[rs20170808@gmail.com]

Can a deethanizer column work without reflux?

[PhilippM]

The entire rectifying section of the column is nothing more than a very large pipe in which vapor rises without doing anything if you don't have a reflux of some kind. A pumparound leading to the uppermost tray is also possible, but you need liquid to flow down and get in contact with the vapor in order to achieve any separation.

[Chemitofreak]

Can I know the reason why have you ask such kind of question?

 

I assume that a every Chemical Engineer know the reason for having a reflux in a Distillation Column.  

 

If not then, reflux provides cooling and condensation of the up-flowing vapours thereby increasing the efficiency of the column.

Edited by Chemitofreak, 18 September 2019 - 02:40 AM.

[PingPong]

In general: reflux is required for a distillation column if there is a purity spec on the distillate, which is normally the case.

 

However if there is no spec on the distillate then the distillation column could be designed as a stripper with part, or all, of the cold feed entering on the top tray.

 

So if one does not care how much LPG (and heavier) is present in the fuel gas product from a deethanizer then one could design it as a stripper. This would then however result in unnecessary loss of valuable LPG to fuel so even when one designs the deethanizer as a stripper, with cold feed to the top tray, one would normally add a small condenser to recover most of this LPG from the overhead and send it back into the column as a small reflux mixed with the feed.