Influences of Axial Mixing of Continuous Phase and Polydispersity of Emulsion Drops on Mass Transfer Performance in a Modified Rotating Disc Contactor for an Emulsion Liquid Membrane System
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- 作者：Lelin Zeng ; Li Yang ; Qi Liu ; Wensong Li ; Yunquan Yang
- 刊名：Industrial & Engineering Chemistry Research
- 出版年：2015
- 出版时间：October 14, 2015
- 年：2015
- 卷：54
- 期：40
- 页码：9832-9843
- 全文大小：647K
- ISSN：1520-5045
文摘
A mathematical model considering the effects of axial mixing of continuous phase and polydispersity of dispersed emulsion drops was developed to describe the mass transfer mechanism of an emulsion liquid membrane (ELM) in a modified rotating disc contactor (MRDC). The calculated results indicate that the axial mixing lowered the concentration gradient along the column, and the polydispersity caused the maldistribution of the interfacial area and the volume for the different sized drops, which also reduced the mass transfer performance. In order to evaluate the degree of the axial mixing and the polydispersity, the important variables affecting axial dispersion coefficient (EM), emulsion phase holdup (桅), and drop size distribution (伪 and 尾) including rotating speed, flow ratio, total flow, surfactant concentration, and stirring paddle width were also studied. It was found that the standard deviation of the drop size (尾) had same variation trend as the mean drop size (伪). The increase in the rotating speed and the paddle width enhanced the turbulence which increased the EM and the 桅 and simultaneously decreased the 伪 and the 尾. The increase in the flow ratio markedly increased the 桅, the 伪, and the 尾, whereas the increase in the total flow signally increased the EM. The increase in the surfactant concentration primarily decreased the 伪 and the 尾; meanwhile, the membrane leakage was obviously inhibited. Finally, the dimensionless correlations were established to predict these hydrodynamic parameters (EM, 桅, 伪, and 尾) with the AAREs of 5.2%, 7.5%, 2.7%, and 4.4%, respectively.