Flare knock-out drum

Company / operator legend practice (API 6A, API 521, API 537) / PIP PIC001 / API 521

Drawn as

A horizontal drum with flare inlets at one or both ends on top, the gas outlet to the flare from the top centre, and a liquid outlet underneath (often to pumps).

Meaning

Flare KO drum: catches liquid droplets before the flare. Becomes horizontal-separator with service KO, fed by the flare header.

Variants

Vertical KO drums are drawn as a vertical vessel
Liquid seal drums (water seal) are drawn with a dip pipe