2 replies to this topic

[gupta rajesh]

How is packing hold up volume is related to column flooding. Is there any thumb rule to know it as percent of packing volume or HETS to relate it to flooding. This question is regarding IMTP70 packed H2S absorber.

[siretb]

The liquid holdup is directly linked to how close you are from flood point.
Normally, with random packing the liquid holdup will be near 3%. You may have more. When you approach Flooding, this holdup can get up to 10%, and then... you flood. You have to account for foaming tendency, also

I would advise you have a look to
Packed towers in processing and environmental Technlogy, by Reinhard Billet. ISBN 3-527-28616-0

The HETS height equivalent to a transfer stage, will decrease just before the flood point, meaning that, just before the flood point you more efficient. This is a very unsafe tregion to operate into because your flowrates will not be absolutely steady, and a little upset means you initiate flooding. The recommendation is never to operate a packed column (absorber) beyond 80% flooding)

[USR]

from what i have understood from the flooding loading curves that is pressure drop vs. gas flow rate at a particular liquid flow rate..the pressure drop increase closely follows gas flow rate increase in the loading region...but at flooding point there is a steep increase in pressure drop...this basically occurs because at high gas flow rates the gas flow is resisted by the high liquid hold up which occupies a significant portion of the tower cross section..(the increased liquid hold up is caused due to the high gas flow rate which restricts liquid flow)