Hi,
I am in the midst of sizing a PSV that is used to protect hydrocyclone. Fire exposure is the only viable relief contigency I can think of. Can anyone shed some light what other credible scenario could be?

Besides, I would appreciate if someone can explain to me what happen to the fluid in the hydrocyclone when it is exposed to fire, will it liquid vapourization or gas expansion in the vessel?

Thank you in advance.

If the hydrocyclone design pressure is identical to upstream system design pressure, then probably fire case is the only relief contingency.

During fire, the hydrocyclone is filled (almost 100%) with heavy (e.g. produced water) and light liquid (e.g. condensate). Liquid expansion and/or vaporisation are likely. The most difficult part is if the two phase relief can occur in the PSV due to liquid flashing, foaming tendency, etc...
Gas expansion will only occur for extended fire case where all liquid vaporized and relieved...

Hi Joe,

I appreciate your valuable input. Thanks.