Effects of Channel Size on the Mass Transfer Performance

4 Effects of Channel Size on the Mass Transfer Performance 

The extraction of dioxouranium(VI) ions from nitric acid solutions (3 M) by TBP/ [Cqmim] [NTf2] (30 %, v/v) in channels with different diameters (0.5-2 mm), was measured for different residence times, flow rate ratios, and mixture velocities, with a mean relative error of 4.3 %. To smdy the effects of residence time (i.e. t = Vd,/ Qmix) on mass transfer at the different channel sizes, the channel length was varied from 10.5 to 31.5 cm. In Fig. 6.10 the extraction efliciency (%Eeff) of dioxouranium 

The effect of mixture velocity on extraction efficiency can be seen in Fig. 6.11 for the three different channel sizes. The length of the channels was in all cases equal to Lch = 10.5 cm. The results illustrate that for a given channel size, as the mixture velocity increases, the extraction efficiency decreases, and that for the same mixture velocity the extraction efficiency is always higher as the channel size decreases. 

An increase in mixture velocity decreases the residence time available for mass transfer. At the same time, as the mixture velocity increases, the recirculation time within the plugs decreases and consequently the mixing becomes more intense (see Fig. 5.17). In addition, the specific interfacial area available for mass transfer 

6 Liquid-Liquid Mass Transfer Using Ionic Liquids 

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