Journal article
On the Combinatorial Part of the UNIFAC and UNIQUAC Models
Technical University of Denmark1
Center for Phase Equilibria and Separation Processes, Department of Chemical and Biochemical Engineering, Technical University of Denmark2
Department of Chemical and Biochemical Engineering, Technical University of Denmark3
Center for Energy Resources Engineering, Centers, Technical University of Denmark4
The excess Cibbs energy of liquid mixtures may be predicted using group contribution models (f.ex. UNIFAC and ASOG), or it may be correlated using molecular models such as UNIQUAC. Group contribution models and the UNIQUAC model contain a combinatorial contribution which accounts for size- and shape-effects and a residual contribution which accounts for interactions among groups or molecules.
A new expression for the combinatorial contribution is given which yields much improved predictions of the excess Gibbs energy of systems where the residual contribution may be expected to be zero (e.g., mixtures of aliphatic hydrocarbons). It is shown that it is advantageous to incorporate the new combinational expression into future modifications of the UNIFAC model.
Language: | English |
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Year: | 1980 |
Pages: | 253-258 |
ISSN: | 1939019x and 00084034 |
Types: | Journal article |
DOI: | 10.1002/cjce.5450580218 |