Drum Type Vessels

A.  Liquid drums are usually horizontal.  Gas/Liquid separators are usually vertical
B.  Optimum Length/Diameter ratio is usually 3, range is 2.5 to 5
C.  Holdup time is 5 minutes for half full reflux drums and gas/liquid separators
Design for a 5-10 minute holdup for drums feeding another column
D.  For drums feeding a furnace, a holdup of 30 minutes is a good estimate
E.  Knockout drum in front of compressors should be designed for a holdup of
10 times the liquid volume passing per minute.
F.  Liquid/Liquid separators should be designed for settling velocities of 2-3 inches/min
G.  Gas velocities in gas/liquid separators, velocity = k (liquid density/(vapor density-1))^0.5,
where k is 0.35 with horizontal mesh deentrainers and 0.167 with vertical mesh deentrainers.         k is 0.1 without mesh deentrainers and velocity is in ft/s
H.  A six inch mesh pad thickness is very popular for such vessels
I.  For positive pressure separations, disengagement spaces of 6-18 inches before the mesh
	pad and 12 inches after the pad are generally suitable.