Compounds Equilibrium calculations

[Vanessa]

Hi

I am doing, mineral processing simulation and I had to add some compounds on my own. I was able to create a package in TEA but my challenge is of the compounds added, cobalt sulphate and sodium metabisulfite show the following error when I try to add them as feed streams.

"Failed to calculate feed stream: CalcEquilibrium failed: CalcEquilibrium failed: CalcEquilibrium failed: TP flash failed: Failed to obtain vaporPressure for compound Sodium Metabisulfite"

How can I correct this error? I have attached the flowsheet.

[jasper]

You are using NRTL for the liquid. This implies that the fugacity is calculated from the saturated vapor fugacity and the activity contribution. Therefore the vapor pressure must be known.

If these compounds can only appear in the liquid phase - just make the vapor pressure really low (e.g. a constant, 1e-100):

Screenshot 2021-12-20 164451.png (7.69 KiB) Viewed 181171 times

Same for cobalt sulphate. Then select T-correlation to be used for vapor pressure:

Screenshot 2021-12-20 164130.png (16.37 KiB) Viewed 181171 times

Unless these compounds to appear in a solid phase (and only in solid)? In this case, vapor pressure is not needed - all that is needed is density, enthalpy and entropy contributions:

[link]https://www.cocosimulator.org/index_help.php?page=TEA/solidonly.htm[/link]

[Vanessa]

Thank you for the information. These compounds should only appear in the liquid phase. I have entered data for the vapour pressure but I am still getting the following error.

[Vanessa]

.

[jasper]

Did you both enter vapor pressure data for these compounds, and select the vapor pressure routine for these compounds as shown in above images?

[Vanessa]

Yes, I did. I have attached the flowsheet.

[jasper]

Please make sure to also select the temperature correlations:

Screenshot 2021-12-22 092322.png (15.2 KiB) Viewed 181126 times

[Vanessa]

Thank you. It is now working after selecting Lee Kesler.

[jasper]

I suggest you do not use Lee Kessler for these compounds. Use the T Correlation instead, as you have defined it (a small value). With Lee Kessler you will probably find that a significant amount of these compounds will go to the vapor phase.