6 replies to this topic

[alles]

can any1 tell me wat are 2 possible causes of high liquid level in the bottom of a distillation column?
pls give me a brief explanation. thks

[Ankur Shah]

hey!

firstly, why are u looking for 2 causes????

i would say the mail problem would be of insufficient heat being sent in through the reboiler. gen all DCs have a liquid level at the bottom though.

someone, please correct me if i am wrong.

thanks!

Ankur

[abhi_agrawa]

As per my understanding of Distillation, a high liquid level in the column sump can be due to insufficient bottoms product draw from the column. If the product draw from the column is less than the requirement for the material balance, liquid will accumulate in the sump and the liquid level wil keep on increasing. This will lead to the flooding of the column. The flooding will start from the bottommost tray.

I do not think that less reboil would lead to an accumulation in the column sump. It will only change the operating line and the product quality will suffer.

abhishek

[virat_chem05]

hi, i think, level at bottom increase , when we decrease the residue withdrawl, when all other parameter does n't change like, reboiler vapour , feed quantity and all temp and pressure condition.....

[Thushara]

Reduction of heat energy to the distillation clmn
High reflux

[sheiko]

Alles,
Excessive pressure drop and pressure build-up in the reboiler return line or liquid level control loop failure can also lead to the rise of the liquid level inside the column.
But what is your exact problem regarding this subject? What is the context?

Edited by sheiko, 22 November 2010 - 01:44 PM.

[rathodms]

Alles,

there are quite a few reasons for increase in the liquid level at the bottom of the distillation column.
1. low pressure drop across the column
this can happen because of
a. low vapor flow ( insufficient heating in the reboiler) or
b. increase in the back pressure of the column downstream.

2. low liquid / residue withdrawl from reboiler
reasons for this to happen can be reboiler liq. outlet control valve failuare/ problems in level control system

3.high reflux flow
- again this can happen because of faulty control system or the failure in coolant valve to the condenser


regards,

Madan.

Edited by rathodms, 30 December 2010 - 06:16 AM.