Binary Data Fill for Liquid Activity Methods

This window is used to define the method for supplying binary activity coefficients that are missing from the equation of state databank(s). Note that when values are estimated by one of the methods below, the estimated data are used to regress activity coefficients for the Liquid Activity Method that has been selected for the simulation.

Mark this checkbox to supplement activity coefficient data with data from the azeotrope data bank. When checked, the azeotrope data banks are searched after searching the activity coefficient data banks, and before invoking any estimation method selected below. When the checkbox is left unmarked, the azeotrope data bank does not influence activity coefficient values. This option may be used with any of the estimation options.

Click the radio button of the estimation method to generate missing activity coefficient data. The estimation method fills parameters still missing after the activity coefficient data banks (and the azeotrope data bank, if checked above) have been searched. The available fill options are:

None	No fill; all missing parameters are set to zero.
UNIFAC	The original UNIFAC method, where the van der Waals area and volume parameters are calculated from individual structural groups. It provides good order-of-magnitude estimates.
Connectivity Index (CI) UNIFAC	This is also called as CI UNIFAC, where the original UNIFAC method is used along with CI databank. The UNIFAC ”r;CI” bank is a self-contained VLE bank. Most of the VLE data in the UNIFAC ”r;SIMSCI” bank also shows up in the CI bank. This means the CI bank can be used standalone. In CI-UNIFAC fill option, main group interaction parameters data for UNIFAC structural groups is taken from CI bank and is used to calculate van der Waals area and volume parameters. The SIMSCI bank also contains LLE interaction data, but the CI bank does not contain LLE interaction data.
Lyngby	A modified version of UNIFAC that includes a three-parameter temperature-dependent form for the binary interaction parameter. In general, this generates better estimates than original UNIFAC. The keyword for this method is UFT1. The temperature-dependent portion of this method has the form: where To= 298.15K
Dortmund	Another form of the UNIFAC method that employs a quadratic temperature-dependent equation. The temperature-dependent portion of this method has the form: This generally is recognized as being developed more fully that the Lyngby form. The keyword for this method is UFT2.
Regular Solution	This fills missing parameters using the Regular Solution Theory developed by Hildebrand. It requires values for pressure, liquid molar volumes, and solubility parameters. It is suitable for nonpolar mixtures, but should not be used with highly non-ideal systems. Liquid molar volumes are measure at 1.0 atmosphere and 77F (25C). Users should be aware that this differs from standard liquid densities (or specific gravities) which are measured at (60F or 15.5556C).
Flory-Huggins	This method often is considered a correction to the Regular Solution Theory method. It considers the entropy effects of mixing molecules differing greatly in size. That make is suitable for polymer/solvent systems, especially when the molecules are non-polar.

All these methods, with their governing equations, are thoroughly discussed in the PRO/II Reference Manual, Volume I, Chapter 2.

Press the OK button to confirm the choices and exit the window. The Cancel button discards any changes.