LIQUID SEALS ANS KNOCK-OUT DRUMS
Liquid seals and/or K.O. drums may be designed as horizontal vessels located at a reasonable distance from flares or as vertical vessels in which case they can be incorporated at the base of the flare. A good design indicates to locate the vessels as close to flares as possible in order to avoid condensate accumulation in the flare header.
LIQUID (WATER) SEAL
K.O. Drums are designed to remove effectively entrained liquid droplets from the flaring gases. Removal of entrained liquid from the flaring gas is very important for two reasons. Primarily, the presence of liquid in the flaring gas promotes intense smoke during combustion. Also, if liquid passes through the flame at the flare burner it will cause “flaming rain” onto the ground below causing a serious safety problem. The design of these drums is based generally on the criteria defined in API RP-521 and it considers residence time and drop-out velocity of the liquid particles in the vapour flow. K.O. Drums can be designed as gravity separators and in this case they are usually horizontal vessels installed at a reasonable distance from flare.Also they can be designed as centrifugal separators (cyclones) installed vertically at flare base. In this type of separators the flaring gas enters tangentially into the vertical vessel. K.O. Drums will be designed to avoid the accumulation of hydrocarbon liquid and they are equipped with instrumentation, control and pumps.
COMBINED K.O. DRUM / LIQUID SEAL DRUM