A distillation column can flood due to dry damage, undersized liquid downcomers, high liquid level in the bottom of the tower, foulcommonly encountered in natural gas conditioning. The troubleshooter should first check for flooding due to excessive vapor velocities. The following correlation may be used for trayed columns 2 feet or more in diameter with a standard 2—foot tray spacing:
This equation is not intended for design purposes; rather it is based on field observations for towers exhibiting noticeable but tollerable glycol looses. These towers had been in service for some time and had been exposed to a moderate amount of fouling. If the actual volume of gas exceeds the allowable volume as calculated above, you may be confident that an intolerable glycol loss is due to an excessive vapor velocity. Note that for sizing a new contactor tower, a coefficient of 2.0 in the above equation would be suitable.