3 replies to this topic

[divyas]

Are pumps required for the reboiler and condenser in a distillation column?

[USR]

I have not seen pumps used for the purpose of reboiling because I have basically worked with thermosyphon reboilers. I guess forced circulation reboilers are in use somewhere because I can remember having read about them. But in thermosyphon reboilers the circulation of the reboiling liquid is purely  by the principles of natural convection. For condensers also there is no need for pumps as flow is generally by gravity.

[divyas]

I was asked this question and i answered that in case of reboilers it depends on the operating pressures, if the column is at a higher pressure pump will not be required and for the case of condensers pumps are not required. I did not mention anything about reflux.

So was it a completely wrong answer then?

[Art Montemayor]

Divyas: 

 

You were not completely wrong; but you were still wrong.

 

The question is: Are pumps required for the reboiler and condenser in a distillation column?

 

The correct answer is: It depends on the type of reboiler and condenser that are employed.  A distillation column’s pressure does not determine whether a pump is required to allow a reboiler or a condenser to operate successfully on the column.

 

However, a pump is required to make a pump-through reboiler work.  Additionally, a pump is required to make an overheads condense work when the condenser is located at grade level.  Both of these pumps can be eliminated if a thermosyphon or kettle reboiler is used and if an elevated condenser is employed over the top of the column to allow gravity return of reflux.