Overfilling tower

[BZLAM21]

Hi;
I want to calculate the overfilling time of a distillation tower in case of blocked outlet . So i have to consider the height of the column from the bottom till the feed nozzle or the gas outlet nozzle on the top.Is there a specific way to calculate it or any other considerations.
Best regards.

 

[georgeverghese]

There will be some liquid holdup in each tray that should be accounted for in this estimate.