Gas alarms activated without any gas leak

Asked by Normandy 7 years, 6 months ago | 2 Answers

What can be the root causes of a gas alarm going off without any gas leak on a FPSO?

2 Answers

pasmith 7 years, 6 months ago

The followings may also contribute to the gas detectors going off:

  • If FPSO was deployed to a field producing crude oil with a higher condensate fraction
  • Failure to recognize or assess the risk posed with the condensate removal package out of service and effect of cargo venting

Normandy 7 years, 6 months ago

Then it could be any of the following causes:

  • A combination of condensed Hydrocarbon vapors, and no-wind conditions probably allowed a slug of condensate to be discharged directly above the HVAC air intakes at the aft of the FPSO.
  • Undispersed Gas/Condensate released from Cargo tank vent pipe
  • Incorrect location of vent for crude containing residual gas (HAZID/HAZOP)
  • Inadequate design of condensate removal system (HAZOP)
  • On/off control of tank venting higher quantity of gas (Controls Philosophy)
  • Vent pipework design allowed condensate slug to form (Piping Design)
  • Operating without normal conditions – Production mode with Condensate removal system shut down was not formalized

​Anyone else has more to share or comment?