API RP 12J, Ninth Edition, 2024 – Process Design of Oil and Gas Separators and Scrubbers

API RP 12J provides requirements and recommendations for the process design of pressure-vessel-based gas–liquid and gas–liquid–liquid separators operating on static facilities and facilities subject to motion such as floating production, storage, and offloading (FPSO) and tension leg platforms. Separators covered by this document may be vertical (e.g. scrubbers, knockout drums) or horizontal (e.g. free water knockout) and are limited to those containing conventional, longstanding, separation internals such as inlet devices, mist eliminators, agglomerators, and distribution baffles. Other internals such as solids jetting systems are addressed by company requirements and/or technology supplier designs.

As instrumentation is a key part of separator design, guidelines are given for the pressure, temperature, and level sensors necessary for separator process control and troubleshooting.
While there are well-established mechanical design codes for pressure vessels, the process and mechanical designs are related and as such should not be performed as separate exercises. General steps in establishing the parameters to consider when designing the mechanical aspects of the separator are also included.

Separators outside the scope of this document include spherical separators, flare knockout drums, electrostatic separators, inline separators, mono-cyclone separators, filter separators, de-oiling equipment, and de-sanding equipment.