×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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

Jobs

Natural Gas Relief Valve Detection

Natural Gas Relief Valve Detection

Natural Gas Relief Valve Detection

(OP)
Hello,

I have an application where we are removing the sulfur from natural gas via carbon beds at less than 15psig. We have relief valves on the tank, and if they were to pop off, we would obviously want to automatically shut off the supply.

Is there some type of sensor that could be placed on the vent stack from the relief valve that would detect the presence of natural gas (potentially with little to no sulfur!) that we could use to communicate with the main supply valves?

I've explored the use of a standard flowmeter, but my concern is that it may get false readings, or be hard to maintain it's accuracy. Also, I'm afraid it may not function properly during a short pop off burst of the relief valve.

Additionally, this will be at an unmanned site, so reliability of the equipment is a must.

Any direction or suggestions would be welcomed.

Thanks,
David

RE: Natural Gas Relief Valve Detection

LEL detector near the nozzle outlet?

Some PSV manufacturers offer a 'lift' indication.

http://www.leser.pl/pdf/czujnik_ruchu.pdf
I'm sure I remember one of the PSV vendors talking about it, Farris, AGCO?

RE: Natural Gas Relief Valve Detection

I prefer prevention, like a pressure transmitter on tank with set point just below PSV set pressure. There's probably (plans to have) a PT on the tank anyway.

If you still need detection - how about a rupture disk under the PSV with a BDI?

Good luck,
Latexman

RE: Natural Gas Relief Valve Detection

A differential pressure switch across the valve?

Best to you,

Goober Dave

Haven't see the forum policies? Do so now: Forum Policies

RE: Natural Gas Relief Valve Detection

(OP)
I've discovered that Leser offers a prox switch on their valve to indicate when it has lifted. Seems a bit more reliable than flow meter/detectors. Might have to investigate if other manufacturers have similar options.

RE: Natural Gas Relief Valve Detection

Silvz71 - yes, most other major manufacturers can supply that same switch. It's simple, cheap, and highly reliable. It fits onto the valve bonnet where the cap is installed, directly sensing movement of the valve stem.

US EPA is currently getting industry comments on new regulations that would require the owner to detect releases from PSVs in defined services. If this becomes law, these lift detectors will become common.

RE: Natural Gas Relief Valve Detection

Will the PSV often pop?

IF not then: Consider a bursting disc upstream your PSV. Pressurize the void space between the disc and the PSV (e.g. with N2) and then have a PALL at the SP of your PSV? Its a bit heavy on instrumentation but its a viable way? If your gas is sour you may also save someting on the PSV since now you can make it "non NACE".

Best regards

Morten

RE: Natural Gas Relief Valve Detection

You can actually buy a rupture disk holder with a sensor attached - it will alarm via a set of contacts.

RE: Natural Gas Relief Valve Detection

How about a noise detector? I've only been around a few PSVs that opened unexpectedly, but each time I went for hours with no hearing afterward.

Best to you,

Goober Dave

Haven't see the forum policies? Do so now: Forum Policies

RE: Natural Gas Relief Valve Detection

Seems silly, but we actually witnessed a plant with a vibration switch clamped to the body of the PSV.....seemed to work but I didn't stamp the drawings.

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!


Resources