JOURNAL OF CHEMICAL ENGINEERING OF JAPAN
Print ISSN : 0021-9592
Volume 21 , Issue 1
Showing 1-18 articles out of 18 articles from the selected issue
  • TADACHIKA SENO, SHIZUO KAGEYAMA, RYUZO ITO
    1988 Volume 21 Issue 1 Pages 1-5
    Published: February 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    The behavior of vortex rings in the initial region of an axisymmetric pulsed jet was simulated by replacing an annular shear layer with a particular vorticity distribution by an array of discrete vortex ring filaments. This modeling was restricted to an inviscid and axisymmetric condition. Consequently, the detailed structure in a real jet cannot be explained by this model. Nonetheless, it provided a good representation of the rolling-up of the shear layer, the vortex ring formation and the transport velocity of the vortex ring. The experimental result, that the pattern of vortex ring formation was roughly classified into three types by Strouhal number, was also explained by this model. The behavior of the vortex ring after formation (for example, vortex ring coalescence) was successfully simulated by replacing a vortex ring by a single vortex ring filament. It was found that vortex ring motion in the initial region of a jet was essentially inviscid.
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  • MASAKUNI MATSUOKA, AKIRA SUMITANI
    1988 Volume 21 Issue 1 Pages 6-10
    Published: February 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    When crystalline particles of binary solid solution mixtures of the m-chloronitrobenzene-m-fluoronitrobenzene system were placed in an atmosphere at elevated temperatures close to their equilibrium liquidus point (sweating), they gradually changed their compositions to approach the equilibrium solidus composition and also changed shape from rigid plates to porous ones. These changes continued even after 360 h, which is significantly different from the behavior observed for simple eutectic systems reported in a previous study. Quantitative analysis of the rates of composition changes were made on the basis of the diffusion mechanism of the recrystallization process during sweating.
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  • XIA HUANG, HAJIME UNNO, TAKASHI AKEHATA, OKIHIKO HIRASA
    1988 Volume 21 Issue 1 Pages 10-14
    Published: February 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    The effects of salt solution on water-absorbing temperature-sensitive poly(vinylmethylether) gel (PVMEG) prepared by γ-ray irradiation were experimentally studied. The swelling and shrinking behavior of PVMEG were affected solely by the kind and concentration of anion group independently of relevant cation. The equilibrium volume of gel in a salt solution was determined by both the valency and radius of the anion group. The transition temperature of PVMEG, below and above which the gel swells and shrinks, respectively, was 310 K independently of the kind and concentration of salt.
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  • YAN SUN, TAIHEI NOZAWA, SHINTARO FURUSAKI
    1988 Volume 21 Issue 1 Pages 15-20
    Published: February 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    The gas-liquid volumetric oxygen transfer coefficient in a three-phase fluidized bed bioreactor was studied using Ca-alginate gels as the solid phase. The coefficient, kLa, in three-phase fluidized beds was smaller than that in bubble columns, regardless of gel diameter. This result was a new finding, and was shown to be characteristic of low-density gel beds. The value of kLa decreased with decreasing gel diameter and with increasing particle concentration in the liquid suspension. This indicates that an optimal gel diameter and particle concentration exist in application of gels to the bioreactor. Dimensionless correlations are proposed for kLa and εG.
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  • YAN SUN, SHINTARO FURUSAKI
    1988 Volume 21 Issue 1 Pages 20-24
    Published: February 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    The volume-surface mean diameter of bubbles dvs was measured using the electroresistivity probe method. From the mean bubble diameter and volumetric mass transfer coefficient kLa, interfacial area a and mass transfer coefficient kL were obtained. The solid phase, Ca-alginate gels, had almost no effect on bubble breakup, and a decrease in kLa with decreasing gel diameter was found to be caused by the corresponding decrease in kL. The mean bubble diameter increased significantly with increasing particle concentration. The value of kL was not affected by particle concentration. Thus, a decrease in kLa with increasing particle concentration was mainly attributed to the corresponding decrease in interfacial area. Dimensionless correlations were proposed for dva, a and kL.
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  • GUANG-WEN WU, NAI-WEN ZHANG, XI-YIN ZHENG, HIRONOBU KUBOTA, TADASHI MA ...
    1988 Volume 21 Issue 1 Pages 25-29
    Published: February 20, 1988
    Released: April 19, 2006
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    Isothermal vapor-liquid equilibrium data of four binary systems -carbon dioxide+pentane at 311.15 and 329.15K, +diethyl ether at 313.15K, +methyl terf-butyl ether at 310.15, 329.15 and 338.15K, and +1-pentene at 303.15, 313.15 and 328.60 K-were determined by using an apparatus with vapor and liquid alternative circulation over a pressure range from 0.5 to 9.1 MPa.
    Experimental data were correlated by applying the Soave-Redlich-Kwong equation of state with the conventional quadratic mixing rule and the DDLC-EOS unified model based on the conformal reference state. Results show that both models correlate the present data satisfactorily.
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  • MASAHIRO HASEGAWA, KUNIO ARAI, SHOZABURO SAITO
    1988 Volume 21 Issue 1 Pages 30-35
    Published: February 20, 1988
    Released: April 19, 2006
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    The encapsulation of a fine inorganic powder for its surface modification was carried out by heterogeneous polymerization of methyl methacrylate in water. The powder used was calcium carbonate and the initiator was potassium per suit ate. The surfactant, sodium dodecyl sulfate, was adsorbed onto the powder prior to the polymerization. The polymerizations were conducted with various amounts of adsorbate and at constant concentrations of the powder, monomer and initiator, under a nitrogen atmosphere in an agitated tank. Time-conversion curves obtained varied remarkably with the amount of adsorbed surfactant. A simulation of the rate of polymerization was attempted by application of kinetic models previously applied to soapless emulsion polymerization in the absence of powder.
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  • ENHAO WANG, HIDETAKA HATANAKA, SHINJI IIJIMA, TAKAHIRO TAKEBAYASHI, ZH ...
    1988 Volume 21 Issue 1 Pages 36-40
    Published: February 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    From the amount of alkaline solution supplied for neutralizing the broth, lactate concentration was estimated on line in the fermentation of Streptococcus cremoris. Cell concentration in the broth was also monitored on line using a turbidimeter. The monitoring system was applied to the culture accompanied by filtration, and both cell and lactate concentrations were controlled at constant levels by on-off control. In this culture, cells and lactate were continuously produced at constant rates, and the concentrations in the fermenter were kept constant.
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  • SHIGEHARU MOROOKA, KATSUKI KUSAKABE, ATSUO KOBATA, YASUO KATO
    1988 Volume 21 Issue 1 Pages 41-46
    Published: February 20, 1988
    Released: April 19, 2006
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    The fluidity of submicron powders was studied in a small-scale transparent column. Powders of Ni, Si3N4, SiC, Al2O3 and TiO2 were smoothly fluidized when gas velocity exceeded the apparent minimum fluidization velocity. The electrical conductivity of the particles did not affect the fluidizing quality in the range of the present experiments.
    All the tested submicron particles formed agglomerates during fluidization. The agglomerate size and the apparent minimum fluidization velocity were dependent on species of particles and fluidizing gas. The equilibrium size of agglomerates calculated from the apparent minimum fluidization velocity and the sedimentation velocity was in the range of 70-700 μm. However, the agglomerates of CaCO3 and ZrO2 were very cohesive and could not be evaluated. The primary particle size was not a proper measure for the classification of fine particles.
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  • MASAO YAMAZAKI, KAZUSHI FUKUTA, YUAN-HENG LI, JUN-ICHI TOKUMOTO
    1988 Volume 21 Issue 1 Pages 47-56
    Published: February 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    Spatial distribution of emulsion-phase porosity and bubble frequency in a fluidized bed of cracking catalyst are determined by use of a seven-channel light transmission method developed for this purpose. The bed was operated at moderate gas velocity at atmospheric pressure or at low gas velocity in slightly pressurized conditions.
    Conversion was calculated by taking into account the physical properties of the emulsion phase such as porosity, interstitial gas velocity and volume fraction. Experiments revealed in general the non-uniform features within a bed; therefore reactant concentrations and conversions calculated numerically were compared with those from the analytical solutions for an isothermal first-order reversible reaction.
    The conversion in the emulsion phase was almost completed at 0.1m height above the distributor. Hence, the overall conversion was controlled in the bubble phase. Increasing bed pressure was accompanied by a decrease in the volume fraction of the emulsion phase, and the pressure effect on the overall conversion at the exit of the dense phase under 300 kPa, for example, amounted to approximately seven percent gain in conversion in comparison with the case of atmospheric pressure, when other factors such as reaction scheme, reaction rate, gas exchange rate and volume fraction of catalyst in bubble phase were assumed to be independent of pressure.
    It was also suggested that the conventional two-phase theory seemed to give approximately 1% higher conversion than the numerically calculated figure under the same assumptions.
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  • YOSHINORI ADACHI, HIDEZUMI SUGIE
    1988 Volume 21 Issue 1 Pages 57-63
    Published: February 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    With the linear mixing rule for a covolume parameter of a cubic equation of state, the calculated excess thermodynamic properties depend on the cohesion parameter only at the specified temperature, pressure and mole fractions. Any cubic equation of state with modified conventional mixing rules gives similar predictions of the excess molar enthalpy and the excess molar volume. The excess thermodynamic property calculations are strongly dependent on the binary interaction parameters of the modified conventional mixing rules. A new method to predict a mixture thermodynamic property is proposed which combines a cubic equation of state for the excess property and a correlation method or experimental data for the pure property.
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  • KOJI TAKAHASHI, TOSHIYUKI YOKOTA, HIROTAKA KONNO
    1988 Volume 21 Issue 1 Pages 63-68
    Published: February 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    A huge number of data prove that the dimensionless mixing time of pseudoplastic liquids with a helical ribbon impeller increases with an increase in the apparent Reynolds number in the laminar flow region, but starts to decrease with the Reynolds number above a certain critical Reynolds number. The mixing time is strongly affected by the liquid shear-thinning property, increasing as the liquid shear-thinning property increases. The mixing time in the laminar-flow region is correlated with liquid properties, impeller geometry and operational conditions. The optimum impeller geometry for the mixing of pseudoplastic liquids is predicted.
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  • WOO SIK KIM, HEE OEUL SONG
    1988 Volume 21 Issue 1 Pages 69-74
    Published: February 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    This study is concerned with anti-precipitation experiments to extend the life cycle of PCM by adding Celite, and also to determine melting heat transfer characteristics experiment of PCM in a PCM cylindrical heat exchanger with six fins. Experimental results are compared with theory to investigate the appropriateness of the unsteadystate two-dimensional heat conduction equation, and the effects of fluid inlet temperature and flowrate on the total melting time of PCM are investigated. Experimental results show that the optimum PCM mixture is 70.5 weight percent of Glauber''s salt and 0.25 weight percent of Celite as thickener, and they are within 5 % agreement with the enthalpy model. It is confirmed that the heat transmission enthalpy model is appropriate for analysis of the melting heat transfer characteristics of PCM. The total melting Fourier number has the following relationships with respect to the Biot number and Stefan number.
    (NFo)m=0.0551(NBI)-0.343(NSTE)-0.733
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  • NORIYUKI YAMADA, NORIO OUCHIYAMA
    1988 Volume 21 Issue 1 Pages 75-79
    Published: February 20, 1988
    Released: April 19, 2006
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    Based upon an analysis of the Kozeny-Carman equation, a general expression was developed for the fluid drag on a particle which is different in size from the other particles in the bed. It is expected that the limitations of usage of the general equation derived will be the same as for the Kozeny-Carman equation, except that the porosity dependence on the solid fraction of specified species in the theory should be determined otherwise. An interesting effect of the size ratios on the fluid drag was illustrated by use of past experimental data on packing porosity. The present analysis suggests a way of estimating the fluid drag on a particle in assemblages of solid particles of various sizes.
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  • SETSURO HIRAOKA, IKUHO YAMADA, TSUTOMU ARAGAKI, HIROYUKI NISHIKI, AKIO ...
    1988 Volume 21 Issue 1 Pages 79-86
    Published: February 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    A numerical algorithm for three-dimensional laminar flow in an agitated vessel was established by using the vector potential and the vorticity. This algorithm was applied to the numerical analysis of the velocity profile of a highly viscous Newtonian fluid in a closed cylindrical vessel with paddle impeller, because of the simplicity of the boundary conditions. The governing equations were solved by using the S.O.R. method. The calculated velocity profile agreed well with that observed by Yamamoto in the region between impeller and vessel bottom, where the boundary condition in the numerical analysis almost satisfied his experimental conditions. As the flow pattern near the impeller was scarcely affected by the nonexistence of a free liquid surface, the numerical results for power input and discharge flow rate coincided well with those observed by Nagata and Yamamoto.
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  • YASUSHIGE MORI, HITOSHI OHYA, HARUHIKO ONO, WATARU EGUCHI
    1988 Volume 21 Issue 1 Pages 86-91
    Published: February 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    Solvent extraction has recently attracted major interest for industrial-scale separation of lanthanoids, alike ion exchange. It is well known that di(2-ethylhexyl)phosphoric acid (henceforth D2EHPA) is an effective extractant for the mutual separation of lanthanoids, because of its high separation factor. 2-Ethylhexylphosphonic acid mono2-ethylhexyl ester (henceforth EHPNA), which is similar in its chemical structure as D2EHPA, has a higher ability of back extraction at low acid concentration than D2EHPA.
    In this paper, the extraction equilibrium of cerium, praseodymium and neodymium by EHPNA was investigated and was compared with that by D2EHPA.
    It was found that the existence of two kinds of complexes should be considered in the region of high concentration of EHPNA, unlike the case of D2EHPA. The extraction of metals from the solution of mixed lanthanoids can be explained based on the extraction mechanism of individual elements.
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  • HIROSHI IKEDA, HIDEKI ASABA, YASUSHI TAKEUCHI
    1988 Volume 21 Issue 1 Pages 91-97
    Published: February 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    Removal of H2S, CH3SH and (CH3)3N, mixed with air in a concentration range from 10 to 800 ppm at 303 K, by use of activated carbon impregnated with NaOH or Na2CO3 (IAC) or sulfonated activated carbon (SAC) was studied to obtain the basic data useful for design of a deodorization process.
    For the system of IAC-H2S or CH3SH, the adsorption equilibrium was of rectangular type and adsorption capacity could be increased as much as about 40 to 60 times of that of original carbon. For the system of SAC-(CH3)3N, the adsorption equilibrium obeyed the Freundlich equation and the effect of sulfonation was much larger when the concentration of (CH3)3N was lower in comparison with the original carbon.
    Intraparticle effective diffusivity, Dic or Diq, was determined by curve-fitting of calculated breakthrough curves with experimental ones. The value of Dic or Diq decreased with the increase of the amount impregnated or the amount of acidic functional groups (-SO3H and -COOH) introduced by sulfonation.
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  • YASUSHI TAKEUCHI, TAKASHI SUZUKI, HIRONORI ARAI
    1988 Volume 21 Issue 1 Pages 98-100
    Published: February 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
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