The program Recval3 is used for the rapid simultaneous regression of any number of binary phase equilibrium and excess property data sets. The following data can be included:

Data Types	Liquid Phase Models	Vapor Phase Models
Vapor-Liquid Equilibria Activity Coefficients at Infinite Dilution Azeotropic Data Liquid-Liquid Equilibria (Isoactivity) Excess Enthalpies Excess Heat Capacities Solid-Liquid Equilibrium Data (Eutectic Systems)	Regression Models Margules Van Laar Wilson NRTL UNIQUAC FlexQUAC Calculation Models (requires Predict Add-On) UNIFAC mod. UNIFAC COSMO-SAC COSMO-RS(Ol)	ideal Redlich-Kwong Soave-Redlich-Kwong Peng-Robinson Chemical Theory Hayden-O'Connell

Up to quadratic temperature dependence of the binary interaction parameters is supported. The format is compatible with major process simulators. Regressed parameters are reported in DDBSP and Aspen Plus format and can be exported to the parameter data bank ParamDB for further use.

Numerous dialogs allow detailled control over regression settings such as:

pure component vapor pressure adjustment to authors or user values for each component and data set
initial parameter values, step-width, convergence criterion
pure component properties used in the regression
weighting factors of data points, data sets, data type
up to three different deviation types for each data point can be simultaneously minimized (absolute and relative deviations in pressure, temperature, vapor mole fraction, activity coefficient, ....
data points inside the miscibility gap can be automatically excluded
...

Regression results are available as short or detailed text output or via a multitude of graphical representations. User settings for the different plots are stored with the project files. Data points in the plots can be selected and the resp. data point and data set dialogs for the marked point or data set can be accessed via the context menu.

The following figures show a few of the possible graphical representations for a regression of data for the system ethanol - acetone using NRTL:

Scientific Papers

2009	Recommended NRTL Model Parameters by Simultaneous Correlation of VLE, Infinite Dilution Activity Coefficients and Excess Enthalpy Data	Tochigi K., Rarey J., Gmehling J.	Journal	J.Chem.Eng.Japan, 42, 6, 376 380 (2009)
1989	Ermittlung Optimaler Modellparameter zur Beschreibung des realen Verhaltens von Nichtelektrolytsystemen durch simultane Anpassung an verschiedene Thermodynamische Daten	Rarey-Nies J.R., Tiltmann D., Gmehling J.	Journal	Chem.Ing.Tech., 61, 5, 407 410 (1989)