Equilibrium calculations based on the Extended UNIQUAC model can be performed by calls from visual basic programs such as Microsoft Excel®. Dynamic Link Libraries (DLL-files) containing simulation tools for solid-liquid equilibrium and vapor-liquid equilibrium calculations are available. A sample program can be downloaded for free. The program includes the ions Na+, H+, Cl-, HSO4-, SO42-, and OH-. Based on the users input of temperature and composition, the program performs:
The calculation accuracy achieved with this sample program is typical for the performance of the extended versions of the program too. The license will expire after approximately one year. After the license has expired, you can come back and download a new version. The sample program comes with a short manual, that explains about installation and use of the program.
Extended versions of the program containing additional groups of compounds can be generated. More advanced versions of the program with multi phase flash (vapor-liquid-solid and vapor-liquid-liquid-solid equilibrium calculations) can also be provided.
The program is called via the Microsoft Excel® file included in the download. In the excel file you will see a number of calculation examples including:
A phase diagram for the binary NaCl - H2O system:
A phase diagram for the binary Na2SO4 - H2O system:
A phase diagram for the binary NaOH - H2O system:
A triangular phase diagram for the ternary NaOH - Na2SO4 - H2O system at 30°C
A Phase diagram for the Na2SO4 - H2SO4 - H2O system at 82.5°C:
Osmotic coefficients for Na2SO4 in dilute and in supersaturated solutions at 25°C. The precipitation of glauber's salt, Na2SO4·10H2O starts at 1.9 molal Na2SO4:
Mean molal activity coefficients of NaCl solutions at 50°C. The experimental data in this plot are from Clarke E.C.W. and Glew, D.N., Evaluation of the thermodynamic functions for aqueous sodium chloride from equilibrium and calorimetric measurements below 154 C., J. Phys. Chem. Ref. Data, 14(1985)489-610 (2):