Butane Storage Bullet PSV or RD
Butane Storage Bullet PSV or RD
(OP)
I have an existing PSV on a butane bullet which is set at 250 PSIG. The PSV is too small for fire sizing. I have two choices: (1) Replace the PSV with a larger one or (2) Add an additional rupture disk to give the required relief rate. The vessel MAWP is 300 PSIG. I am thinking about installing a 300 PSIG rupture disk on the vessel. With fire sizing, I have thought about incidents where the metal weakens and the vessel explodes. A rupture disk would prevent this. How many of you do the above or protect your bullets with rupture disks? Any other ideas or comments are greatly appreciated. Thanks.





RE: Butane Storage Bullet PSV or RD
What are the incidents you are referring to?
RE: Butane Storage Bullet PSV or RD
RE: Butane Storage Bullet PSV or RD
1) There are few convenient methods to stop a release if the disk happens to activate.
2) Would you really send an operator out (in a fire) to block an activated disk?
2) An open disk is path for possible flame flash back into the tank.
3) The fluid will auto-refrigerates but hopefully not below the minimum metal temperature.
This sounds like an application for dual safety valves.
RE: Butane Storage Bullet PSV or RD
No doubt you can install a small PRV for small relieving scenario and a large relief device for large relieving load. This is pretty common in many installation.
Neither PRV nor RD will definitely protect a vessel from fire. Vessel will eventually collapse due to fire. Nevertheless, PRV (RD even better) may minimize catastrophe failure of vessel and buy time for passive protection.
One of the problem of installing RD is premature opening due to fatigue failure and lead to unnecessary release of inventory. Another issue is premature opening due to RD manufacturer tolerance.
Still think that a PRV is a better consideration...
JoeWong
Chemical & Process Technology
RE: Butane Storage Bullet PSV or RD
RE: Butane Storage Bullet PSV or RD
Best regards
Morten