CI-UNIFAC - Description

This is also called CI-UNIFAC, where the original UNIFAC method is used along with CI databank. The UNIFAC "CI" bank is a self-contained VLE bank. Most of the VLE data in the UNIFAC "SIMSCI" bank also shows up in the CI bank. This means the CI bank can be used standalone. In CI-UNIFAC, 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.

SIM4ME Thermo 3.4 has introduced CI UNIFAC fill option where it retrieves all the binary interaction parameters from UNIFAC "CI" bank. This is integrated in PRO/II 9.1 for the "Liquid Activity" thermo methods whereever UNIFAC estimation method is accessible. The calculations are same as UNIFAC method. We can’t retrieve main group interaction parameters data from CI bank for LLE and VLLE cases. But, it is handled to use VLE data if LLE data is not available for CI UNIFAC fill option in PRO/II. The bank search order is applied on a group-group pair basis. The bank search order for a group-group pair stops as soon as some data is found in a bank.