Liquid-dispersed contactors

TABLE 22-5 Comparison of Axial-Dispersion Coefficients for Several Liquid-Solid Contactors... 

Fig. 2. Typical data for the bubble-size distribution in a gas-liquid dispersion produced in a new type of contactor without a pressure drop per stage (G4). Dispersed phase air. Continuous phase water. The solid lines were calculated from Eq. (17) and Eq. (258) or (260). [after Gal-Or and Hoelscher (G5)].

Horizontal contactors are essentially bubble columns with an aspect ratio less than one, and the gas is sparged at the bottom as turbulent jets. In order to get fairly uniform gas-liquid dispersion, multiple injection points are employed for the gas. The gas-liquid contact can be further improved using impellers (Fig. 33). The impellers are of a modified propeller type and are mounted on a horizontal shaft. 

The determination of the driving force for the interfacial mass transfer is very difficult in extraction columns since no pure plug flow exists within the column This is one of the most important differences between gas-liquid and liquid-Uquid contactors. Because of the small density differences in liquid-liquid systems there exists a relatively high rate of axial backmixing of dispersed as well as of continuous phase. Backmixing reduces the concentration differences along the column height. 

Unique also is the extensive analysis of dispersed phase systems, whether these are gas bubbles in liquids, sprays, a liquid-liquid dispersion or a liquid-solid system. Characteristics of different contactors for such systems are summarized in Tables 1.1 to 1.3 and Figs. 1.1 and 1.2. 

Continuous liquid/disperse gas-phase contactors (Type B)... 

Separation of Ionic Liquid Dispersions in Centrifugal Solvent Extraction Contactors, Sep. Sci. TechnoL, 41(10), pp. 2205-2223. 

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