PSV Discharge Coefficient for Dense Phase Fluids 1

[ChemEngSquirrel]

I'm sizing a PSV for a dense phase fluid. It will enter the PSV as dense phase but will become two phase leaving the PSV.

What discharge coefficient should I use for preliminary PSV sizing. Based on API 520 Part 1 guidance I'm unsure whether to use 0.975 (gas) or 0.85 (two phase).

Thanks.

 

[apetri]

see the discussion about rigorous models in API,
you may try to estimate the vena contracta conditions and then decide which parameter to apply, for the procedure see

"

http://eng-tips.com/viewthread.cfm?qid=329093"

 

[EmmanuelTop]

Without further information available from vendors, value of 0.85 should be assumed.
See also the attachment and

http://people.clarkson.edu/~wwilcox/Design/reliefv2.pdf

and

http://frame.leser.com/engineering/...Code-Sect-VIII-and-API-RP-520-and-API-521.pdf

for further info.

Dejan IVANOVIC
Process Engineer, MSChE

 

[EmmanuelTop]

And the attachment.

Dejan IVANOVIC
Process Engineer, MSChE