Lee Kesler Plocker on Hysys

[Abirus]

Hello, while using the EOS of Lee Kesler Plocker for the degassing of oil, I got one vapour phase and two liquid phases as a result. Can anyone please explain why I got two liquid phases? (Knowing that when I use the EOS of Peng Robinson I get only one liquide phase but a flow of vapour that equals zero). Thank you in advance.

 

[PaoloPemi]

in principle many thermodynamic models including cubic EOS (Soave, Peng-Robinson ...), corresponding states (Lee-Kesler...) etc. can predict multiple liquid phases...
but it could also depend from some numerical instability in the solver (Lee-Kesler has multiple roots) and so on...
I am not familiar with Aspen (I utilize mainly Prode Properties library) but I assume that solver is stable, if you thing the result is not correct check for abnormal values of critical properties or interaction parameter...