Drain systems

PAB 2073

Drain Systems

Drain systems are important to allow equipment to be drained, opened, inspected and repaired

If else, process fluids would have to be collected in containers to prevent spillage to sea

Drain pipings ran throughout the platform and routed to vessels (caissons) on the lowest level of the platform – gravity drainage

2 separate drain systemsOpen drainClosed drain

OPEN DRAIN SYSTEMS

Open drain systems deals with drain fluids at atmospheric pressure

Open drain lines converge into headers and then flow to Open Drain Caisson

Water is then disposed into sea and oil is skimmed off and pumped into Closed Drain Vessel

Open Drain Caisson has atmospheric vent to release gas

Example drain linesDeck drains Drains under vessels, pumps, equipment

skidsRainwater, chemicals from chemical injection

package, spent lube oil from generators, diesel fuel overflow and wash water from decks

CLOSED DRAIN SYSTEM

Process drain system Closed drain lines connects to a Closed Drain

Header and fluid flows to a Drain Vessel Drain vessel separates oil and water, oil pumped

back to oil surge vessel, water disposed to sea via Closed Drain Caissons

Closed Drain Caissons has pumps to return skimmed fluids back to Drain Vessel

Closed Drain Caisson has atmospheric vent to release gas

Example closed drain linesHydrocarbon liquid lines from water treatment

tanks, fuel gas filter separators, flare scrubbers

High Pressure Drains from wellheads, hydrocarbon vessels low points and instruments and pipeline pig launchers

Drain Vessel last separation stage before closed drain fluids go to

caissons Gas line to atmospheric vent Internals to separate oil and water

Oil water separation section Oil boot Water overflow section

Pump to return oil into the main separation process Water flows into Closed Drain Caisson