Floating Roof Tank Vapor Recovery System

Floating roof tanks reduce the vapor space above the stored liquid, but vapor can still be released through seals, fittings, product movement, roof movement and connected transfer operations. A recovery system must account for the roof design, tank pressure behavior and the way vapor is collected.

Design points for floating roof tanks

Point	Questions for the project
Roof type	Is the tank an internal or external floating roof tank? How is vapor controlled around the roof and seals?
Seal and fitting condition	Are seals, vents, legs, gauges and fittings maintained and suitable for the product?
Vapor collection	Where does vapor enter the header, and how does the connection move with the roof?
Transfer operation	What flow peaks occur during filling, emptying or loading?
Pressure balance	What pressure and vacuum limits apply to the tank and recovery header?

Typical equipment arrangement

The system may include a flexible or guided vapor connection, knockout and filtration, pressure control, recovery process, liquid return and instrumentation. Condensation + adsorption and adsorption + absorption are both reviewed against the vapor composition and operating cases.

Maintenance and operation

• Inspect seals, fittings, flexible connections and drains.
• Check liquid carryover and filter condition.
• Track pressure drop, bed temperature and valve switching where applicable.
• Confirm the recovery system does not create excessive backpressure.
• Keep emergency isolation and bypass procedures available to operators.

Information required for equipment sizing

Provide tank drawings, roof type, seal arrangement, product composition, tank dimensions, transfer rates, pressure settings, vapor connection details, climate, utilities and the desired recovery or emissions objective.

Related: skid-mounted VRU · equipment supply scope.