combining two property packages within one

[jasper]

That document seems incomplete - the stream is not associated with a property package (and there are two) and hence has no input compositions.

[Stephan]

Indeed. Please connect teststream to prop pack test18.
This should reproduce te error,
when combining water and methanol within the teststream.

[jasper]

You set up ChemSep as fugacity provider instead of letting ChemSep solve the flash. ChemSep does not provide fugacity derivatives.

Instead, set up a new TEA package. Then start with loading a ChemSep package as the equilibrium provider:

Screenshot 2020-10-13 113612.png (3.15 KiB) Viewed 11630 times

then you can use the equilibrium server as calculation method as well. And you can add other external calculation methods.

Let me know if the trouble continues.

[Stephan]

I have done the recommended settings.

Calculations work now.

However, they are quite slow.

Solving a flowsheet that consists of one stream only takes up to 30 seconds,
although Cofe shows a solving time of 50 ms.

Using TEA-internal models and equilibrium solver results in much faster calculations,
However, this is not an option due to the absence of desired models.

Is there any trick to avoid those long calculation times?