6 replies to this topic

[Zack Adam]

Hi,

Really need your experties advice...

How to size the PSV for the flowline? I have seen one of our design consultant qouted that the governing case is SSV leakage. I am not so sure since I could not find such case in API 520.



Regards
Zack

[Zack Adam]

Hi,

Really need your experties advice...

Sorry, I have made a mistake on the Flowline PSV Sizing....

It should be called Production Header PSV Sizing....

How to size the PSV for the Production Header ? I have seen one of our design consultant qouted that the governing case is SSV leakage. I am not so sure since I could not find such case in API 520.



Regards
Zack

[pleckner]

Please define "SSV" and be a bit more specific. Sounds like a leaking control valve or such. Yes?

[Zack Adam]

Dear Phi...

SSV is a surface safety valve (shutdown valve). To my knowledge, I never come across any of the SSV that will cause any overpressure in production header.


Regards

Zul

[djack77494]

Zack,
I think the situation you describe is common in oil production facilities, especially when producing from high pressure reservoirs. You normally flow from a well through various safety-required open/close valves and through a "choke". Downstream of the choke, the pressure is much lower, and often so is the design pressure of piping and equipment.

One of the key overpressure hazards that must be examined is what happens when the outlet side of things gets isolated; e.g. a block valve closed. If all valves worked perfectly, this would not be a problem. However, there will be leakage through "closed" valves, which are the devices intended to isolate the well from the production header. (No one expects the choke valve to be leak-tight.) Thus you must consider the case where a downstream valve is closed (and it seals perfectly), but there is leakage through your primary line of defense against overpressure - the SSV. You then design a PSV to protect the piping and equipment from this hazard.
HTH,
Doug

[muralimuthu]

Hi,

Really need your experties advice...

How to size the PSV for the flowline? I have seen one of our design consultant qouted that the governing case is SSV leakage. I am not so sure since I could not find such case in API 520.



Regards
Zack

Hi,

Flowline PSV sizing willl be of blocked case. no need of doing other cases, just check it should not cross crical pressure and temperature of the fluid while sizing

regards,
M.Murali
process Engineer,
Petrofac

[JoeWong]

Hi,

Flowline PSV sizing willl be of blocked case. no need of doing other cases, just check it should not cross crical pressure and temperature of the fluid while sizing

Agree with blocked discharge case.

Any specific reason should not cross critical pressure ?
What to do if cross critical pressure ?