In mass transfer operation of a cross-currently contacting system of two fluids, it is theoretically discussed how the change of outlet concentrations caused by the variations of inlet concentration and flow rate are affected by the degree of longitudinal mixing of a fluid. The degree of mixing is expressed by “diffusion model” and “mixing cell model, ” and the transfer functions are derived for both mixing models. In each model, the effect of mixing on the transfer functions is concentrated only in the “Mixing function” MD (s) or M_p (s) defined by Eq.(18) or (35) in this paper. The mixing functions for unsteady state, M_D (s) and M_P (s) are seriously influenced by the values of Pe and n respectively. The transfer function is considerably affected by the degree of longitudinal mixing of a fluid whose dynamics is under consideration, while the other transfer functions for concentration change and for flow rate change are not greatly influenced. In addition, it is pointed out that the results based on these two models are different from each other even if both models are quite equivalent from the steady state viewpoint.

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“Modified cold bypass operation” which the author has tentatively named, is called alien cold bypass operation in oversea literatures.
This operation specifies itself with those chemical equilibrium changes through the addition of a coolant.
Optimization of this kind of operation is already reported by R. Aris in his book. However, his method was through dynamic programming.
The author derived here an optimization theory for the same through analytical procedures, which saves much labor in the trial and error in design calculation.
The author divided modified cold bypass operations into two divisions for the convenience of analysis.
1) Pure modified cold bypass (special)
2) Hybrid modified cold bypass (more general)
Optimization conditions for several conceivable cases were derived. These necessary conditions are expected to be applicable in the designing of multistage reaction operation.

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In this paper, it is shown that the problem of the stability of the fluidized bed reactor for the heterogeneous exothermic reaction can be considered in a similar way as for the homogeneous process, except for a few points; e.g., the elutriation of particles and the number of the phase in the reactor.
By using the dimensionless basic equations as shown in equations (12), (13), (14) and (15), the Routh-Hurwitz formulae are obtained. Since these formulae are too complicated to determined the stable operating conditions, the approximate formula is developed.
As an example of the heterogeneous exothermic process, the oxidation of low grade coal with air is carried out in the fluidized bed reactor. From equations (16) and (17) and, the experimental results of gas analysis, the specific rate of reaction is obtained as shown in Fig. 8. From equations (18) and (19) and the results of gas temperature measurement in the reactor, the specific rate of heat generation by reaction is obtained as shown in Fig. 9.
By using these experimental results and the inequality (33), the stability of reactor is discussed.

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In this paper, it is shown that the specific rate of heat generation by heterogeneous exothermic reaction is obtained by the measurement of the reaction temperature change in the fluidized bed reactor, and that this method is available when the composition of both the basic material and reaction products is not sufficiently known and the composition of each solid particle is not uniform.
As an example of the heterogeneous exothermic reaction, the oxidation of low grade coal with air is selected. From the equation (13) and the curve of the reaction temperature change as shown in Fig. 3-7, the specific rate of heat generation by the reaction is obtained. The results are shown in Fig. 8-9. From these, it is found that the relation between the specific rate of heat generation by the reaction and the reaction temperature is described by Arrhenius equation and the apparent activation energy is about 17 (Kcal/mole) in the range of T₇=600°K-900°K.

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A continuous process of manufacturing Ethylsilicate (Si (OEt) ₄) from EtOH and Tetrachlorosilane (SiCL₄) was developed.
This reaction is the rapidly consecutive reaction, remarkably exothermic, and generating a large quantity of HCL. Furthermore, the formation of the byproduct (polysilicate) increases when the reaction temperature rises above 0°C, and therefore there must be rigid control of the reaction temperature. From thermodynamic calculation, it was concluded that the calolification in the reaction was almost all caused by the heat of the solution of HCl in unreacted EtOH. When EtOH containing the suitable quantity of HCl is used, the calolification in reaction is not evolved.
Basing upon this conclusion, the continuous process was developed and carried out on a small pilot plant scale using EtOH-HCl. Reactor consisted of two stages, the first was a jet pump, and the second a stirred tank.
Data showing the effect of flow ratio (EtOH/SiCl₄) and concentration of HCl in EtOH on the yields of Si (OEt) 4 were presented. From these results, the optimum condition was determined and the cost of production of this continuous process compared with that of the former batch process.

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To establish the continuous distillation system of crude lactam obtained by the neutralization of isomerized cyclohexanoneoxime, a pilot plant test was carried out.
Based on the preliminary consideration of crude lactam, the first column test was made to separate water cut, lactam cut and residue and it was observed that a continuous operation is possible by discharging about 3% of residue to feed and that the concentrated crude lactam is preferable from the standpoint of yield.
To scale up the above system, Kestner and wetted wall type evaporators were used and the overall heat transfer coefficients were measured. The results show Kestner type to be better than the wetted wall type because of the completeness of the evaporation. The consequent continuous distillation of lactam cut was carried out and lactam of a quality and distillation yield better than the batch system was obtained in this continuous system.

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On the pressure drop across Venturi scrubbers in high temperature region, few reports are available. Precooler is sometimes used to cool hot gases, but in order to pass hot gases of over 700°C directly into Venturi scrubbers, it is necessary to know about this pressure drop.
The author applied an equation Δp=k_pu_t²·γ/2g (1+L) to experimental results in which k_p was the correction factor, and making a study of the relation between k_p and the temperature drop across the Venturi scrubber obtained a relation k_p=3 (Δt)-0.28.
With the relation to dust collection efficiency, it is said that the pressure of injection water should be made higher the more the throat diameter of Venturi scrubbers is enlarged, but actually the injection pressure seems to have only slight effects on the pressure drop of Venturi scrubbers.
The author performed experiments on this point, and ascertained that the pressure of injection water seems not to affect so much to the pressure drop of gas, as far as the range of water pressure is from 0.3-2.0kg/cm², as is ordinary used.

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