JOURNAL OF CHEMICAL ENGINEERING OF JAPAN
Print ISSN : 0021-9592
Volume 12 , Issue 6
Showing 1-18 articles out of 18 articles from the selected issue
  • TAKAO SUZUKI, TADASHI UCHIDA
    1979 Volume 12 Issue 6 Pages 425-429
    Published: December 20, 1979
    Released: April 03, 2006
    JOURNALS FREE ACCESS
    A numerical solution is examined for calculation of the effectiveness factors for porous catalyst particles in the case of isothermal first-order reactions at steady state, as analytical solutions become complicated for irregular shapes.
    The correctness of the model and of the numerical solution is demonstrated by comparing the results obtained for cylindrical extrudates with the analytical solutions derived from diffusion limitation theory.
    The numerical solution was applied to the calculation of the effectiveness factors for extruded catalysts with various kinds of cross-sections, i.e. circle, capital letter L, dumbbell, trilobe and quadrulobe. Calculations show that non-cylindrical extrudates have effectiveness factors equivalent to those of cylindrical extrudates if the characteristic particle size is expressed as a ratio of particle volume to external surface area. Thus numerical analysis makes it possible to estimate the effect of diffusion limitation on the activity of any shaped catalyst.
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  • RYUZO ITO, TADACHIKA SENO
    1979 Volume 12 Issue 6 Pages 430-435
    Published: December 20, 1979
    Released: April 03, 2006
    JOURNALS FREE ACCESS
    Axisymmetric jets issuing from pipe, nozzle and orifice were observed to investigate the effect of exit geometries on downstream behavior, using the hydrogen bubble method for flow visualization. It is found that the disturbance mode on the jet column depends on boundary layer thickness, δ, at the exit. A thin boundary layer produces varicose (axisymmetric) disturbances, while a thick boundary layer produce helical (non-axisymmetric) ones. The critical value of δ, which distinguishes one mode from the other, is determined as about 0.21 times the exit diameter. In the case of the varicose mode, position and frequency of vortex ring formation, transport velocity and frequency of coalescence are measured and correlated with the operating conditions. Considering the important role of δ on downstream behavior, the Strouhal number, Sr, for various exit conditions is generally defined by taking δ as the characteristic length. A single correlation for the proposed Sr is obtained independent of different exit conditions.
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  • YOSHIKAZU MIYAKE, WATARU EGUCHI, MOTONARI ADACHI, RYUJI TSUKADA, SUSUM ...
    1979 Volume 12 Issue 6 Pages 436-442
    Published: December 20, 1979
    Released: April 03, 2006
    JOURNALS FREE ACCESS
    The effect of the presence of carbon dioxide on the absorption mechanism and the absorption rate of iodine vapor was investigated at 298 K using a laminar liquid jet column and continuous-flow stirred-vessel absorbers.
    The existence of carbon dioxide in the gaseous phase decreased the absorption rate of iodine. The first effect was an increase in the gas film mass transfer resistance. The second effect was a decrease in the hydrolysis rate of iodine dissolved in the liquid phase. This was caused by the competitive base-catalytic hydrolysis of the two acidic gases taking place in the aqueous phase. Moreover, the presence of hypoiodous acid was found to accelerate the hydrolysis rate of carbon dioxide.
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  • KATSUTOSHI INOUE, HIDEAKI OKUBO, FUMIYUKI NAKASHIO
    1979 Volume 12 Issue 6 Pages 443-447
    Published: December 20, 1979
    Released: April 03, 2006
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    The authors previously reported the extraction kinetics of copper by benzoylacetone in a stirred transfer cell and during drop formation. The extraction kinetics of the same system during drop rise is discussed in this paper.
    To interpret the influence of the concentrations of copper and hydrogen ion in the continuous phase and that of benzoylacetone in the dispersed phase on the extraction rate, a theoretical analysis was carried out, taking account of diffusion in a droplet and that accompanied by (1, l)-th order irreversible reaction in the continuous phase.
    On the basis of the results of this theoretical analysis, the experimental results were examined and it was clarified that the reaction which forms chelating complex in the continuous phase can be treated as a pseudo-first order reaction with respect to benzoylacetone under the present experimental conditions.
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  • YUJI SATO, YASUHIRO MURAKAMI, TSUTOMU HIROSE, YOSHIYUKI HASHIGUCHI, SH ...
    1979 Volume 12 Issue 6 Pages 448-453
    Published: December 20, 1979
    Released: April 03, 2006
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    A loop reactor is regarded as a new type of reactor for bulk polymerization of olefins. Several approaches to evaluate its performance are made herein.
    A simple model of discharge flow is proposed and related with the results obtained by measurement of average circulation velocity. The average circulation velocity is proportional to impeller speed and the sine of the impeller blade angle. It depends upon Reynolds number and dimensions of the impeller.
    Flow pattern was measured and the influence of baffles and impeller geometry is discussed qualitatively. In the case of unbaffled conditions, fluid flows in a helical motion. Intensity of this motion increases with impeller speed and pitched angle. In the case of baffled conditions, tangential velocity component is suppressed and normalized distribution of axial velocity is independent of impeller geometry.
    Pressure distribution was measured and pressure loss was obtained. Total pressure loss shows good agreement with the value calculated by superposition of frictional loss in straight parts and bend loss in bends obtained from established correlations.
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  • YUJI SATO, YASUHIRO MURAKAMI, TSUTOMU HIROSE, HIROYUKI YAMAMOTO, YOSHI ...
    1979 Volume 12 Issue 6 Pages 454-459
    Published: December 20, 1979
    Released: April 03, 2006
    JOURNALS FREE ACCESS
    Dilute emulsified particles (≅300 mg•dm-3, da≅8 μm) of heavy oil A were removed in a 50×50mm-square and 0.32m-deep column by flotation using small bubble swarms (da≅80 μm) generated by a rapid depressurization of supersaturated liquid. Pressure at which air was dissolved was varied within 2-4.5×105 Pa. The flotation efficiency is best at 3×105 Pa and decreases at higher pressure in spite of higher bubble holdup, probably because of excessive liquid disturbance.
    The flotation is also influenced significantly by the chemical species added and their concentrations. A solution of pH 4 shows the best flotation in the pH range investigated (pH 2-10). A microelectrophoresis measurement shows that the zeta potential ξ of both oil particle and bubble shifts from positive to negative with increasing pH through a PZC (point of zero charge, ξ=0) around pH 4 and the best flotation at pH 4 can be explained by the great reduction in repulsive interaction of the electric double layer. Flotation efficiencies are improved in CaCl2 and A1C13 solutions with increasing concentration (10-5-10-2 mol-dm-3) while they decrease [slightly in NaCl solution. This trend is discussed semiquantatively in the light of the variation of zeta potential with concentration.
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  • KO HIGASHITANI, YOSHIZO MATSUNO
    1979 Volume 12 Issue 6 Pages 460-465
    Published: December 20, 1979
    Released: April 03, 2006
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    A modified Smoluchowski theory in which the hydrodynamic interaction and Van der Waals-London potential between particles are taken into account is proposed for the rapid Brownian coagulation of colloidal dispersions and compared with experiments on coagulations of polystyrene latex particles in KC1 solutions. It is found that the theory is physically consistent with experiments and predicts the time-dependent behavior of particles for a sufficiently long time with considerable accuracy. The existence of an asymptotic particle-size distribution, the self-preserving distribution, is confirmed by experiments. These results indicate that the theory is applicable to the floe formation process where large and irregular particles are dominant, as well as to the initial stage of coagulation.
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  • KAZUMASA KOBAYASHI, MINORU IWATA, YUKIO HOSODA, HIROSHI YUKAWA
    1979 Volume 12 Issue 6 Pages 466-471
    Published: December 20, 1979
    Released: April 03, 2006
    JOURNALS FREE ACCESS
    Electroosmotic flow through a perforated membrane consisting of straight and circular capillary tubes was analyzed on the basis of the Navier-Stokes equation, taking account of the effect of an electric field. Two cases were theoretically investigated, i. e., that where the volumetric density of true electric charge in the liquid near the wall of the capillary tubes is constant and corresponds to the average, and that where the electric charges in the electric double layer are distributed in the radial direction of the capillary. Experiments were performed under several applied voltages using membranes of various capillary diameters. A single membrane and several membranes with different capillary diameters arranged in series were used. The electroosmotic pressure was directly proportional to electric current density and decreased with increase of capillary diameter. The rate of electroosmotic flow was directly proportional to current density and increased with increase of diameter. These results were in good agreement with the theoretical results derived from the assumption that the volumetric density of true electric charge is constant.
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  • YUSHI HIRATA, RYUZO ITO
    1979 Volume 12 Issue 6 Pages 472-474
    Published: December 20, 1979
    Released: April 03, 2006
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  • AKIRA HIRATA, KOICHIRO KIRA, YOSHIZO SUZUKI
    1979 Volume 12 Issue 6 Pages 474-477
    Published: December 20, 1979
    Released: April 03, 2006
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  • RYUZO ITO, KAORU TOMURA
    1979 Volume 12 Issue 6 Pages 477-478
    Published: December 20, 1979
    Released: April 03, 2006
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  • SHIGERU MORI, AKIRA TANIMOTO
    1979 Volume 12 Issue 6 Pages 478-480
    Published: December 20, 1979
    Released: April 03, 2006
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  • NORIAKI WAKAO, SEIICHIRO KAGUEI, J. M. SMITH
    1979 Volume 12 Issue 6 Pages 481-483
    Published: December 20, 1979
    Released: April 03, 2006
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  • RYUZO ITO, KAORU TOMURA, MASAO YAMAMOTO, YUKIE OKADA, NOBUHIRO TSUBOI, ...
    1979 Volume 12 Issue 6 Pages 483-485
    Published: December 20, 1979
    Released: April 03, 2006
    JOURNALS FREE ACCESS
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  • YASUSHI TAKEUCHI, YOSHITAKE SUZUKI, Em FURUYA
    1979 Volume 12 Issue 6 Pages 486-488
    Published: December 20, 1979
    Released: April 03, 2006
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  • SUSUMU FUKUSHIMA
    1979 Volume 12 Issue 6 Pages 489-491
    Published: December 20, 1979
    Released: April 03, 2006
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  • KAZUMASA KOBAYASHI, MASARU HAKODA, YUKIO HOSODA, MINORU IWATA, HIROSHI ...
    1979 Volume 12 Issue 6 Pages 492-494
    Published: December 20, 1979
    Released: April 03, 2006
    JOURNALS FREE ACCESS
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  • KENJI KUBO, AKIRA MISHIMA, TOSHIRO ARATANI, TAKEO YANO
    1979 Volume 12 Issue 6 Pages 495-497
    Published: December 20, 1979
    Released: April 03, 2006
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