Overall rate of aqueous homogeneous reaction, 2FeCl₃+SnCl₂=2FeCl₄, taking place in aqueous droplets dispersed in continuous benzene-phase in an agitated vessel has been measured experimentally, to know how far the aqueous droplets coalesce and redisperse during the mean residence-time of the dispersed phase.
The agitated vessel is operated in a continuous manner, with aqueous FeCl₃ and SnCl₂ solutions continuously fed and aqueous reaction product steadily taken out. The experimental apparatus and dispersion of the aqueous droplets are illustrated in Figs. 1 and 2, respectively.
When the aqueous droplets coalesce and redisperse so rapidly that the concentration of each droplet is equalized during its mean residence-time, the mean concentration of the aqueous stream outgoing from the vessel should fall, according to the theory, on the curve “Homo-Continuous” in Fig. 4, but when each aqueous droplet behaves independently of one another with neglisibly small coalescence and redispersion, it should fall on the curve “Hetero-Continuous.”
As obvious from the experimental data plotted in Fig. 4, coalescence and redispersion of the dispersed aqueous phase take place only neglisibly under the experimental condition chosen here for the benzenaqueous solution system.

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Attempts were made to increase the heat transfer in a packed bed by soldering the contact points between the wall and packings and among the packings. For the purpose, fused solder was poured into the packed bed kept at a high temperature. The heat transfer was measured by means of the apparatus given in Fig. 2. The overall heat transfer coefficients of the soldered packed-bed were found to be generally several times as large as those of the ordinary packed bed, while the pressure drop did not change appreciably for the same flow of air.
Nusselt number for the soldered steel-ball-packed bed could be well correlated by the following empirical equation:
D_ph₀/k_g=1.26(D_pG/μ(1-ε))^0.576(D_p/D_t)^-0.28
and for the ordinary steel-ball-packed bed:
D_ph₀/k_g=0.778(D_pG/μ(1-ε))^0.576(D_p/D_t)^0.22
The authors, by breaking the soldered steel-ball-packed bed, found that the number of contacts or the number of junctions formed by the hold up of solder for each ball was generally six instead of eight as had often been assumed in the theories on hold up.

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This report has been drawn up as the result of fundamental studies on mass transfer in the centrifugal gas-liquid contactor in which liquid is spouted from the small holes drilled through a rotating cylinder wall, and where gas is sent cross-currently to the water jets in an annular space between the rotating cylinder and a stationary concentric outside cylinder.
Many experiments on pure CO₂ gas absorption by water jets spouting from rotating small holes were carried out at 20°C, and the effects of the following variables on the liquid mass transfer rate were studied: diameter of the rotor, diameter of the small hole, number of the small holes, width of the annular space, gas flow rate, liquid flow rate, revolution of the rotor, time of contact, etc.
In these experiments, the diameter of the small hole was 0.52.0mm, the average velocity of water, 55950cm/sec, and the travelling length of water (the distance between two cylinders), 15cm. Under these conditions, the water jet might present laminar flow. Therefore, assuming that the concentrations of gas and liquid were equilibrium on the interfacial surface, the mass transfer coefficient of the liquid film, k_L, was defined by a well-known Eq. (10), derived theoretically from the unsteady-state diffusion theory. The contact area per unit volume of water jet, a [cm²/cm³], and the liquid film capacity coefficient, k_La [1/sec], was obtained experimentally.
As the result, the following equations were derived:
k_La=2a√D_L/πθ=E_ML/θ
a=0.0875(D_L/πθ)^-1/2(d^-1.2)(r₁n/ω)^β
=36.5(d^-1.2)(r₁n/ω)^β
Where β=0.72 for d≥1.0mm
=3.93d^0.74 for d<1.0mm
The gas absorption rate by water was observed to be large immediately after the liquid was spouted from the hole, as is obvious from above equations. Therefore, for the practical designing of this kind of contactor, it would be advisabe to prepare a multi-rotor-type contactor in order to make many jets of liquid as possible.

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