Mass transfer model for liquid-liquid micromixing systems

The effect of total flow rate on membrane dispersion extraction efficiency was studied for liquid-liquid micromixing systems.Mass transfer coefficient and mass transfer rate were obtained from the experimental results for the micromixing process. In order to predict mass transfer performance of the micromixing process, some traditional mathematical models were tested.Total and individual mass transfer coefficients were calculated, and compared with the experimental results. The results showed that main factors affecting mass transfer coefficients were residence time and droplets size, and mass transfer coefficients increased with the reduction of residence time.Mass transfer coefficients in the micromixing process could reach as much as 1.2×10 -4 m·s -1,which was about 10—100 times higher than that in a traditional column extraction process. The mass transfer performance in the micromixing process could be predicted neither with the model in which mass transfer resistance of any one phase was ignored, nor with the simplified average equations.So mass transfer performance in the micromixing process was much different from the traditional column extraction process.The authors’results showed that mass transfer coefficients could be predicted with the full traditional two-phase resistance model by considering both steady and non-steady states, and the calculated values were in good agreement with the experimental values.