Multiphase phase equilibrium calculation

[RPeter18]

Dear Mr. Morten Hammer,

I hope this finds you well. First and foremost, I would like to express my sincere gratitude for your generous contribution to the Thermopack library on GitHub. It has proven to be an incredibly powerful and invaluable tool, especially for someone like me who is new to both programming and thermodynamic calculations. Your contributions have made thermodynamic calculations more accessible and have been of immense assistance to individuals in the fields of research and engineering.

As a novice in both programming and thermodynamic calculations, I have some questions and would greatly appreciate your guidance:

If I were to make modifications to the Peng-Robinson (PR) equation, would these changes typically be made within the Fortran code and then called upon using Python?

My specific area of interest involves the phase equilibrium of injecting CO2 into oil reservoirs, which typically involves at least three phases: oil, gas, and water. I have noticed that the Python examples provided are primarily focused on two-phase equilibrium using the two_phase_tpflash function. Could you kindly provide an example or guidance on how to compute three-phase equilibrium, incorporating the PR equation of state, as well as possibly PC-SAFT or CPA?

I understand that your expertise in this field is invaluable, and I greatly appreciate your time and consideration in addressing these questions. Your insights would be of immense help as I venture into this complex and fascinating domain.

Once again, I extend my heartfelt appreciation for your open-source contributions that have made a significant difference in the world of thermodynamics. Thank you for your generosity and dedication.

Warm regards,

[morteham]

Thank you for the kind words. I am glad you find Thermopack an interesting tool and consider it for CO2 injection simulations.

The multiphase capabilities are currently limited in the open-source version of Thermopack, but we have flash algorithms we hope to publish in 2024.

Regarding the PR model you can do quite a lot of model tuning from the python side. On init you can define what alpha-correlation to use, and if you are to include volume translations. On init you also define what mixing rules to apply. After init you should also be able to modify the parameters of some of the alpha correlations and the volume translation parameters. You will also be able to modify the interaction parameters like the kijs. Further you should be able to modify the ideal heat capacity parameters using the python interface.

[vegardjervell]

Hi, for tuning cubic models it might be helpful to take a look at this doc page for an overview of the different initialiser keys and available set methods. That page is for ThermoPack v2.1.0 (the current version on PyPI), the docs for the most up-to-date version on GitHub (if you're building from source) are here.