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[Olidin]

Hello,
 

Has anyone dealt with supercritical fluid hydraulics? I have been working with a supercritical relief through a PSV. However, API 520 Part 1 appendix B did not explicitly explain how to calculate pressure drop through piping and fittings.

 

A similar to question raised by djack77494 in This post. And the post concluded with him using HYSYS with Peng-robison equation of states but he did not mention the method chosen for calculating pressure drop via pipe and fittings.

 

My concern is that HYSYS does not seem to have a calculation method for supercritical fluids. According to their Unit Operation Guide, pg 6-54, all 12 methods are "all been developed for predicting two-phase pressure drops".

 

Then I question whether I should trust the simulation file results. Either way, the answer could have been simply: "we don't know, we don't have any research for stuff like that."

 

Has anyone had experience with this?

 

I'm about to resort to basic energy balances and use the simulator for enthalpy and entropy if needed.

[Bobby Strain]

A supercritical fluid is single phase. So no problem with calculation. For the relief valve you must check to determine whether two phases develop in the valve and use the appropriate calculation method. If the outlet is two-phases, then use the two-phase correlations.

 

Bobby