Thermodynamics Research Center / ThermoML | Fluid Phase Equilibria

ABSTRACT

Knowledge of diffusion coefficients in liquids is of great importance for the calculation and simulation of mass transfer processes. In the literature, only a few models for multicomponent diffusion coefficients are found. Due to lack of experimental multicomponent diffusion data, these models have not been verified for real systems until now. To overcome this limitation, multicomponent diffusivities were measured within the whole concentration space of four ternary systems. Fick diffusivities were transformed to less concentration dependent Maxwell Stefan diffusivities using the thermodynamic correction factor. Four prediction models were tested by comparing predicted values with experimental data. In systems with nearly ideal thermodynamic behavior, multicomponent diffusion prediction shows promising results. In strongly non-ideal systems, all tested prediction models show large deviations. Thus, the quality of predicted diffusion coefficients strongly depends on an accurate thermodynamic description of the system.