4 replies to this topic

[awesome]

Guys,

Which EOS is better to be used for Natural gas and why?

I read PR is better as it predicts Liquid densities better than SRK?
Say if you run process simulation in HYSYS one is going to use PR; is this correct?

[Zauberberg]

Using any of the two will yield good results. Peng-Robinson is considered more accurate as it has been continuously updated and upgraded with experimental values, at least according to the software developers.

[PaoloPemi]

In the past PR was considered capable to model better fluids with higher acentric factors (while SRK the best for methane etc.) but now with TWU, Mathias etc. extended Alpha functions this is not true and both can produce very accurate results, check that your sofware does include one of these extended correlations (by the way my sofware has the three TWU parameters for almost all the fluids in database)

[hshethna]

The new version of HYSYS also has GERG which is very accurate for predicting liqui density

[DOXA]

When detailed laboratory analysis is available a common practice is to input those data in software package

however, as no one knows what happens between two successive laboratory measurements the calculated values may be unreliable.
Apart from this a software package offers the advantage to calculate a large number of different properties with great accuracy.
a suitable equation of state (Peng Robinson, Soave Redlich Kwong , GERG or others) can calculate very accurate VLE values, for hydrocarbon mixtures typical errors are whithin 1-2 C of measured values.
For values as density AGA or GERG again are very accurate (typical errors < 0.3%).

Edited by DOXA, 05 December 2011 - 02:43 PM.