KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 7 , Issue 2
Showing 1-22 articles out of 22 articles from the selected issue
  • Gong-Hong Hong, Ryohei Yamazaki, Genji Jimbo
    1981 Volume 7 Issue 2 Pages 109-114
    Published: March 10, 1981
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Slug properties such as minimum bubbling velocity, slug frequency, slug velocity, slug length and bed expansion were measured in a two-dimensional fluidized bed made of quartz glass at different temperatures up to 560°C.
    In the case of large particles (umb > 2.2 cm/s), it was found that slug properties were affected by bed temperature, and that changes of slug frequency and slug length corresponded to changes of minimum bubbling velocities with temperature.
    On the other hand, slug frequency and slug length for small particles (umb < 2.2 cm/s) were found not to change with bed temperature.
    Taking the change of bed temperatures into account, experimental equations of slug properties are presented.
    It was also found that slugging flow pattern was subject to change with increase of bed temperature.
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  • Masayuki Sato, Shigeru Miyazaki, Masao Kuroda, Takeshi Sakai
    1981 Volume 7 Issue 2 Pages 115-119
    Published: March 10, 1981
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    It was found that gas bubbles produced in distilled water developed in exact synchronization with the frequency of an AC potential applied between a nozzle and an opposite earth electrode. The lower limit of frequency of synchronization was similar to the natural bubbling rate without the applied potential. The upper limit was decided by the inner diameter of the nozzle, i.e. the frequency became higher when nozzle size was decreased. The frequency range was from about 10 to 4, 800 Hz within the conditions of these experiments.
    The upper or lower limits of the synchronizing regions were decided by the functions of the applied potential and the inner radius of nozzles where the frequency was constant. The diameter of bubbles being formed synchronously was determined directly by gas flow rate and applied frequency; moreover, the bubbles were essentially uniform in size. In these experiments, uniform bubbles ranging from about 150μm to 5 mm in size were obtained successfully, although they had been difficult to produce by normal methods. The proposed technique should be useful for application in industry and research laboratories where controlled uniform bubbles are required.
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  • Tatsuo Nishimura, Yuji Kawamura
    1981 Volume 7 Issue 2 Pages 120-125
    Published: March 10, 1981
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Flow pattern in the separated region of a single cylinder was studied. In particular, in order to focus on the flow near the surface of a cylinder, diffusional current distribution was measured by an electrochemical method. Furthermore, flow visualization near the surface of a cylinder was performed by the hydrogen bubble method. It was found that the flow pattern in the separated region was divided into two regions, a thin-layer region of reversed flow and a moving-wake region, and these regions varied with Reynolds number (Re= 1, 000 5, 000). On the basis of those results the flow pattern in the separated region was investigated in a wider Reynolds number range, including the results of previous work. It was indicated that at low Reynolds number the thin-layer region of reversed flow was dominant, while the moving-wake region appeared with increasing Reynolds number and spread throughout the separated region at about the critical Reynolds number.
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  • Takeshi Kano, Fumiaki Takeuchi, Eiji Yamazaki, Hidenori Tsuzuki
    1981 Volume 7 Issue 2 Pages 126-131
    Published: March 10, 1981
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    To give a vibratory motion to the pipe used in the plug-type pneumatic conveying of granular materials is thought to reduce the friction of the plug against the wall of the pipe and therefore to save power consumption.
    In this study, the effect of vibratory motion induced in a pipe wall on power consumption is theoretically and experimentally examined.
    First, a theoretical equation for the air pressure required to move a plug through a vibrating pipe is developed.
    Second, the values calculated by the equation are confirmed to be in good agreement with the data obtained in experiments performed using horizontal and vertical pipes 1 m in length and 25 mm in diameter and calcium carbonate powder as granular material.
    It is concluded that the application of vibration to the pipe is effective in reducing power consumption for the plug-type pneumatic conveying of granular materials. The optimum design conditions are briefly discussed.
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  • Katsuhiro Nozawa
    1981 Volume 7 Issue 2 Pages 132-137
    Published: March 10, 1981
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The properties of complex heat transfer by both natural convection and radiation are experimentally observed in the fusion of vertical cylindrical ice.
    Heat transfer of fusion Nucmelt of natural convection on the vertical cylindrical ice is obtained by the following semi-theoretical equation, by taking away radiation heat transfer Nur from the experimental value of complex heat transfer of fusion Numelt.In this case, the range of application is Grl from 107 to 109.
    Nucmelt=0.8Grl1/4
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  • Mitsunori Hozawa, Hiroshi Yokohata, Nobuyuki Imaishi, Katsuhiko Fujina ...
    1981 Volume 7 Issue 2 Pages 138-142
    Published: March 10, 1981
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Liquid-phase mass transfer coefficients kL at the free surface of an agitated vessel were measured by the oxygen tracer method for five solvents (water, methanol, benzene, carbon tetrachloride and nitrobenzene), and the effect of surface tension σ on kL was studied experimentally.
    The following experimental equation, which correlates the data of this work and those of previous workers within 20% average error, is proposed.
    Sh=const.Sc0.5Re0.8 (σ/σW) e6
    e6=-1.05n-0.49
    where (σ/σw) means the ratio of surface tension of the solvent to that of water, and n is agitation rate [1/s].
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  • Toshinori Kojima, Terukatsu Miyauchi
    1981 Volume 7 Issue 2 Pages 143-150
    Published: March 10, 1981
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Extraction and stripping rates of copper by the industrial extraction reagent LIX63 are measured with an extraction apparatus with porous Teflon membrane. Three mass transfer resistances (copper and hydrogen ion in the boundary film of the aqueous phase and reagent in the membrane) are separated and the results are analyzed using the diffusion model accompanied by mono-complex formation and dissociation reaction in the aqueous phase. In the region of NM∝ [(HR) i/ (H*)] 2, extraction rate is limited by mass transfer of the complex in the membrane, and in the region of NM∝ [(HR) i/ (H*)] 2 extraction rate is limited by chemical reaction and diffusion of the complex in the aqueous phase, where NM, (HR) i and (H) * are respectively extraction rate and concentration of active component of LIX63 and hydrogen ion in the reaction zone.
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  • Masaaki Nakamura, Katsunori Tashita, Sachio Sugiyama
    1981 Volume 7 Issue 2 Pages 151-156
    Published: March 10, 1981
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Radial dispersion coefficients of liquid Er in a packed bed with gas-liquid cocurrent upflow were measured in the air-water system with three spheres of 4.0, 5.0 and 6.6 mm diameter, and compared with radial effective thermal conductivities Ker under the same conditions. The following results were obtained :
    1) In the cocurrent upflow system, the flow pattern changes from bubble flow to pulse flow, increasing the gas flow rate at constant liquid flow rate. In the bubble-flow region, Er is very much larger than in the liquid-phase flow, and a maximum value of Er exists. In the pulse-flow region, Er decreases gradually or is constant.
    2) In the previous paper, it was shown that Ker also has a maximum value in the bubbleflow region of the cocurrent upflow system. Effect of the gas flow rate on Er is analogous to effect of the gas flow rate on Ker.
    3) In the pulse-flow region, Er of the cocurrent upflow system is consistent with that of the cocurrent downflow system.
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  • Toshiyuki Yokota, Toshihiko Iwano, Hiromi Deguchi, Teiriki Tadaki
    1981 Volume 7 Issue 2 Pages 157-163
    Published: March 10, 1981
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A new statistical approach is proposed to estimate the light absorption rate in a gas-liquid photochemical reactor in which the light rays were scattered by bubbles. The light absorption rate was estimated, based on the probability distribution function of the light path length in the reaction zone. The distribution function could be determined by the Monte Carlo simulation of the travel of light rays scattered in the reactor.
    Experiments such as photoreduction of potassium ferrioxalate solution with gas bubbling supported the validity of the estimating method described above.
    As a convenient approximation, it was also proposed to consider the light absorption rate in a reactor with no bubbles, computed using the following modified attenuation coefficient μ* as that for a heterogeneous system.
    μ*=μ (1+hψ), h= (3.6/db) 0.66
    where μ is the attenuation coefficient of liquid phase [cm-1], db is bubble diameter [cm] and ψis gas holdup.The equations above are valid for the case of μ<0.4 cm-1. For 0.4 cm-1<μ, the effect of light scattering by bubbles can be neglected.
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  • Toshiyuki Yokota, Toshihiko Iwano, Akira Saito, Teiriki Tadaki
    1981 Volume 7 Issue 2 Pages 164-170
    Published: March 10, 1981
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Photochlorination of toluene was performed in a bubble column photochemical reactor. In the reactor, chlorine was transferred from gas phase to liquid phase and radical reaction was carried out at room temperature by absorption of light.
    From the experimental results, it has become clear that the reaction rate is first order with respect to chlorine concentration and to light absorption rate respectively, and the control stage of rate process under these experimental conditions was a photochemical reaction in the bulk of the liquid phase. The performance of such a photochemical reactor could be estimated satisfactorily from the information about mass transfer and kinetics and the light absorption rate computed by the method based on light path length distribution.
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  • Takashi Fukuda
    1981 Volume 7 Issue 2 Pages 171-177
    Published: March 10, 1981
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Gas-liquid contact areas in baffled horizontal stirred vessels equipped with flat-blade turbines were determined by means of gas absorption experiments on the NaOH-CO2 system and the Na2SO3-O2 system containing cobalt ion as a catalyst, accompanied by a pseudo-first order reaction. Effects of operating conditions, vessel conditions and power consumption on gas-liquid contact area were elucidated.
    Contact areas were correlated with the ratio of liquid volume to vessel volume, vessel length, number of impellers, number of blades and Froude number in the region of relatively low Froude number (Fr<0.8). In the region of high Froude number (Fr>0.8), contact areas were not correlated by Froude number, but by power consumption per unit volume of liquid.
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  • Sachiro Shitaokoshi, Shigeo Goto, Hideo Teshima
    1981 Volume 7 Issue 2 Pages 178-183
    Published: March 10, 1981
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The hydrolysis of ethyl formate in aqueous solution was studied by using ion-exchanger membrane as catalytically active wall in both empty and annular-wall tube reactors. The experimental values of average concentrations were compared with the theoretical ones for both laminar and plug flow patterns. Radial profiles of concentrations were also measured by withdrawing samples at various radial positions. Experimental values for the annular tube reactor were in good agreement with the theoretical ones for laminar flow pattern, but for the empty tube reactor we could not obtain good agreement. Therefore, annular tube reactors are suitable for reaction analysis by using tube wall reactors.
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  • Jusuke Hidaka, Shigeo Miwa
    1981 Volume 7 Issue 2 Pages 184-190
    Published: March 10, 1981
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Penetration testing of powder beds is attempted and dynamic behavior of the powder bed is discussed on the basis of penetration characteristic curves obtained in the testing.
    The penetration characteristic curve is quite sensitive to surface properties of the particles constituting the powder bed. The curves can be classified roughly into two types according to their shape, i.e., stepwise and smoothly continuous curves, which are closely related to the angular property of the powder. This interesting fact suggests that in the yielding behavior of powder beds there are two patterns which are essentially different.
    From consideration of the penetration characteristic curve, it has become possible to discuss the complicated dynamic behavior of powder beds with angle of static and dynamic internal friction.
    The penetration test is an effective tool for estimation and analysis of the dynamic behavior of powders.
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  • Takeshi Sako, Toshikatsu Hakuta, Hiroshi Yoshitome
    1981 Volume 7 Issue 2 Pages 191-195
    Published: March 10, 1981
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Vapor-liquid equilibria of hydrogen iodide-water and hydrogen iodide-water-iodide systems were measured, and the salt effect on the azeotropism was investigated. In the system hydrogen iodide-water-magnesium iodide, the relative volatility increased considerably with increase in salt concentration, and the azeotrope disappeared at 8.5 mole% of MgI2. Furthermore, the relation between azeotropic composition of hydrogen iodide and salt concentration is linear.
    The experimental data were correlated by Hála's empirical method, and the calculated values of hydrogen iodide in vapor phase, y1 (calcd.), agreed very well with the observed values, y1 (exp.), for hydrogen iodide-water and hydrogen iodide-water-potassium iodide systems. However, in the system containing high concentration of magnesium iodide, the two didn't coincide because of the large discrepancy from ideality due to the high ionic strength in the solution.
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  • Masanori Yoshiki, Kazumori Funatsu, Hisashi Shinohara, Toshinori Kojim ...
    1981 Volume 7 Issue 2 Pages 196-213
    Published: March 10, 1981
    Released: November 12, 2009
    JOURNALS FREE ACCESS
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  • 1981 Volume 7 Issue 2 Pages 214a
    Published: 1981
    Released: February 19, 2010
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  • 1981 Volume 7 Issue 2 Pages 214b
    Published: 1981
    Released: February 19, 2010
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  • 1981 Volume 7 Issue 2 Pages 214c
    Published: 1981
    Released: February 19, 2010
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  • 1981 Volume 7 Issue 2 Pages 214d
    Published: 1981
    Released: February 19, 2010
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  • 1981 Volume 7 Issue 2 Pages 214e
    Published: 1981
    Released: February 19, 2010
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  • 1981 Volume 7 Issue 2 Pages 214f
    Published: 1981
    Released: February 19, 2010
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  • 1981 Volume 7 Issue 2 Pages 214g
    Published: 1981
    Released: February 19, 2010
    JOURNALS FREE ACCESS
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