3 replies to this topic

[Adam80]

Hi;

 

I have pipeline transporting propylene at liquid phase (not liquified), for locked in scenario i want to know the P increase due to T increase. intial condition before shut in are; P1=20 barg and T1=-10C, ambient conditions :  P2=???, T2=25C

 

Shall i apply the Equation of state with the corresponding state theory? or

The formula for hydraulic expansion shown in API521, Chapter 15, is it applicable?

 

Cheers.

[Zauberberg]

You can't apply equation of state (used for gases) for hydraulic expansion (liquids). These are two completely segregated phenomena.

 

You can use the equations presented in API 521 section 4.4.12 (the latest API 521 edition). Also refer to http://www.chemwork....l_expansion.pdffor simplified method.

[Adam80]

Thanks

[serra]

for a many liquids you can find values for compressibility and thermal expansion, with these and volumetric expansion of piping (due to temperature and pressure)

you can estimate the P increase  (as suggested by Zauberberg you may find several discussions about this topic)

with an equation of state (you must select a model reasonably accurate for liquid phase, see for example Refprop and some models in Prode)  you can estimate dV/dp and dV/dt , with a EOS you can calculate the values in a range of t, p and fluid conditions.

Edited by serra, 24 September 2015 - 01:11 PM.