Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


Oil Gas Separator PCV - Fail Open or Closed?

Oil Gas Separator PCV - Fail Open or Closed?

Oil Gas Separator PCV - Fail Open or Closed?

I'd like to know which kind of PCV valve to flare should we install to oil gas separator, ie, Fail to Open or Fail to close.

Thanks in davance

RE: Oil Gas Separator PCV - Fail Open or Closed?

Presuming there is no process safety function (i.e it is purely for process controls and it is not meant for ESD depressuring either), I'd go for FC since the hazard imposed by a PCV to flare failing full open are much worse than if the valve were to go FC (flow over load to flare system; high liquid entrainment in vapor stream to flare).
Besides, you've probably got other safety trip loops to address high pressure events on this separator, and you'd most likely want this PCV to go to close position during an ESD, given that one of the causes for an ESD could also be low pressure on the plant main instrument air header ??

RE: Oil Gas Separator PCV - Fail Open or Closed?

I agree, but without knowing what else is there it's difficult to say.

A PCV should not be a pressure safety device and therefore should fail close. There should be further higher integrity devices ( Spring relief valves, bursting discs etc) which protect against high pressure.

I'm more interested to know what this PCV is used for - normal operation?? to flare?? That's a criminal waste of gas if it is.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Oil Gas Separator PCV - Fail Open or Closed?

If its a kind of spill over valve then i would say fail close. If it opens then it would "drain" the pressure of of your upstream vessel. Fail close it will perhaps have to impact or sooner or later the system will trip.

Best regards, Morten

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close