In order to design a sieve plate tower operating at a low gas-liquid ratio, experimental studies were made on the pressure drop and foam height at low gas rates (U=1-8cm/sec) and high liquid rates (L'=1, 200-14, 400kg/m·hr), using several series of perforated plates (Table 1). The results obtained are as follows:
(1) It is considered that ΔP is composed of the sum of ΔPh, ΔPd, and ΔP_σ, as shown by Eq. (1), each of which can be deduced experimentally.
(2) The aerating factor, f, defined by Eq. (5), is represented by Eqs. (9) and (10).
(3) ΔPd can be calculated by Eq. (2). ΔP_σ is independent of gas rates and may be represented by Eq. (11), in case uh>300cm/sec. When uh'<300cm/sec., deviations were observed between the results obtained from Eq. (11) and those by experiments. The data given in Figs. 8 and 9 are to be considered as an anomaly occurring at low gas rates.
(4) The experimental results obtained of h, ΔP_f/ρ_l and ρ_f are classified into two groups with the limiting liquid height (Z+ΔZ=1.3cm) as a deverging point.
(5) In the region where Z+ΔZ<1.3cm, h, ΔPr/ρl and ρf are independent of liquid helghts and can be represented experimentally by Eqs. (12), (14) and (15), respectively.
(6) In the region where Z+ΔZ<1.3cm, h, ΔPf/ρ_l and ρ_f are dependent on liquid heights and can be represented by Eqs. (13), (16) and (17), respectively.

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(1) The equation simplified by Bierlein (Eq. 5) can represent quite well the transient behavior of most of the thermal diffusion process except for the starting period of t/θ 0.4. The authors simplified this Bierleim's rigorous equation still further, obtaining Eq. 9, which showed good agreement with the results of the experiments for the whole period of t/θ.
(2) A graphical method was developed, for estimating the diffusion coefficients and the Sorret coefficients for binary liquid systems, from short-time experiments. Unlike in ordinary cases, when this method was employed, there was no need of continuing the observation until the equilibrium state was reached.
(3) The experimental apparatus of Korsching type¹⁾was compared with that of Tanner type²⁾, and it was experimentally confirmed that the former was practically convection-free but that the latter was not.

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The rate of isotopic exchange between heavy hydrogen and normal water, catalyzed by suspended platinum-active carbon catalyst, was measured in a stirred reactor at atmospheric pressure, and the total rate of exchange, R, was calculated by the use of Equation (15). The rate of strring, the bubbling velocity and the diameter of the catalyst particle exhibited remarkable effects upon the total rate of exchange as shown in Figures 4 to 8 and by Equation (21). It may be concluded that the chemical reaction at the catalyst surface is extremely rapid and the mass transfer of hydrogen through the liquid is the rate-controlling step in this reaction.
Since the total rate of exchange controlled by mass transfer may be related to the over-all mass transfer coefficient by Equation (8), the experimental data on the exchange are to be correlated in the similar way as given in the previous paper(¹⁰⁾) under the assumption that the resistance to the mass transfer consists of two separate parts: namely, the resistance in the liquid surrounding the bubbles and that in the liquid surrounding the suspended solid particles.
The general equation derived from the above assumption:
(22)
was in a satisfactory agreement with the experimental data as shown in Figures 12 to 14. Equation (22) was also compared with the previous one, Equation (23), which had been derived from the experimental data on the hydrogenation of alpha-methylstyrene carried out by using a palladium-alumina catalyst. A fairly good agreement was obtained in the order of the magnitude of the total rate of exchange calculated by means of the two equations that were based upon entirely different chamical reactions which took place in different reactors having different sizes and different mechanical constructions and for which different kinds of catalysts were employed. In order to explore the possibility of employing a single or series of continuous stirred reactors for the commercial production of heavy water, the reactor volume required for obtaining some conversion was estimated for the operation at 100 atmospheres, assuming that the mass transfer remained the controlling step even at such a high pressure.

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This work was undertaken with a view to obtaining a general correlation for liquid phase mass transfer in wetted-wall columns. Studies were made on the absorption of pure solute gases by various solvents in columns of varied dimensions. The column dimensions, the systems employed and the ranges of the variables covered are given in Table 1.
It was observed that the gas rate had no effect on the values of HL when the ReG was below 7, 000 or so, as shown in Fig. 3, and the difference obscrved by Emmert and Pigford4) between the HL valucs for absorption and those for desorption could not be noticed.
The plots of HL vs. Re on logarithmic coordinates showed two distinctly different regions, A and B, as seen in Figs. 4-10. In region A, the values of HL varied with Re^1.0 Sc^0.5 and (μ/ρ)^2/3 but were independent of z and σ. In region B, the HL values were proportional to Re^0.5 Sc^0.38, (μ/ρ)^0.59, z^0.12and σ^0.15
The data we e correlated with Eqs. 12 and 14, for region A and region B. The agreements of the data with the equations were good, as seen in Figs. 13, 14 and 15.

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