In the previous paper
3) the authors discussed the agitation effect on the mixing of the outer side diffusional film of liquid droplets in liquid-liquid systems. In this paper the authors try to clarify the agitation effect on the mixing of the inner part of dispersed droplets.
The interfacial area and mass transfer rate were measured simultaneosly of the systems which were
(a) H
2O-(iso-valeryl chloride)-(α-nitropropane),
(b) H
2O-(iso-valeryl chloride)-tetraline,
(c) H
2O-(iso-valeryl chloride)-(CCl
4+paraffine oil).
Systems followed by diffusion-controlling chemical reaction.
Conclusions:
(1) In the range of low agitator speed, the state of mixing of the inner part of dispersed droplets is nearly equal to that of perfect mixing.
(2) When the agitator speed is increased, the mixing rate of the inner part of droplets is somewhat decreased, as the result, i.e., the increase in mass transfer rate is not proportional to the increase in the interfacial area in a system of Δ
ρ=0
(3) When the agitator speed is increased and the diameter of droplets is decreased, the values of the mass transfer rate, estimated on the assumption that the mass transfer is caused by molecular diffusion only, are nearly equal to the estimated values of the mass transfer rate in perfect mixing. Therefore in the range of high agitator speed, the effect of agitation on the mixing of the inner part of droplets is slight in extent.
(4) Even when high viscosity liquid is used for the solvent of dispersed phase, in the range of low agitator speed, the inner part of droplets represents a state of almost perfect mixing.
(5) Generally speaking, in liquid-liquid extraction systems the difference in density between phases is not large, so that the increase in agitator speed has its effect principally on the increase in interfacial area.
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