What's the difference between Thermodynamic Frameworks? AQ, MSE vs MSE-SRK?

The limits are thermodynamic framework dependent. There are three frameworks available in OLI Software. MSE (default in version 11.5), MSE-SRK, and AQ.

1. For MSE the ranges are:

Temperature: Up to 0.9* Tcritical. For a water-rich solution this would be approximately 340 oC Pressure: 1500 Atmospheres Ionic Strength: No limit TDS: No Limit Concentration: infinite dilution to fused salt.

For MSE-SRK the ranges are: Essentially the same as for MSE but targeted at a smaller set of chemistries. In the water-rich liquid phase the ranges are the same.

In the non-water-rich phases (including vapor), CO2 and/or H2S rich in light hydrocarbons – C1 to C7 and pressures greater than 80 bar. I do have a wiki for this: https://wiki.olisystems.com/wiki/MSE-SRK

For AQ the ranges are: The older AQ thermodynamic framework is much more limited.

Temperature: 0 oC to 300 oC Pressure: 1500 Atmospheres Ionic Strength: 30 mol/Kg H2O