Case Study

Flare Header & Knock Out Drum Redesign

Challenge:

A refinery-wide flare study revealed a substantial deficiency in the capacity of a knock out drum in one of our client’s units. Without sufficient capacity or retention time, there was a threat of liquids being sent to the flare tip or vapors being routed to the facility's slop line in the event of system over-pressurization. The existing knock out drum was located underground, which also reduced the ability to inspect and maintain the system. Any modification needed to be completed within an existing turnaround schedule.

Solution:

Valdes evaluated layout options and performed front end and detailed design services to properly size the refinery flare header and knock out drum for increased capacity, as well as to allow the existing UG system to be abandoned. Our design included placing the tank aboveground and elevating the pressure safety valves (PSVs) to prevent any back pressure, and rerouting the header across a 70’ long pipe bridge spanning a refinery access road.

Valdes also conducted a hydraulic analysis of the existing slop line to ensure compatibility with the new system. This involved specification and installation of new pumps and associated piping to transfer slop oil from the new primary Flare KO Drum to slop tanks.

The system was designed to be installed in three phases to coincide and be completed within the facility’s TAR schedule.

Valdes also provided the following:
Selected and specified multi-stage vertical can pumps with seal pots and several flow, pressure, level and temperature instruments and developed a control system strategy to ensure safe, reliable system operation
Provided layout and stress analysis of 2,000’+ of large bore flare header piping
Selected/specified closed loop flare sample station to allow safe sampling of flare gas

Impact:

Valdes delivered a design to install the flare header and knock out drum in three phases to coincide and be completed within the facility’s turnaround schedule. Hydraulic analysis was conducted on the existing slop line to ensure compatibility with the new system. The design incorporated various elements to ensure safe and reliable system operation.

SERVICES: