JOURNAL OF CHEMICAL ENGINEERING OF JAPAN
Print ISSN : 0021-9592
Volume 13 , Issue 5
Showing 1-17 articles out of 17 articles from the selected issue
  • HIROYASU OHASHI, TAKUO SUGAWARA, KEN-ICHI KIKUCHI, MICHIHITO ISE
    1980 Volume 13 Issue 5 Pages 343-349
    Published: October 20, 1980
    Released: April 03, 2006
    JOURNALS FREE ACCESS
    The concentration and velocity profiles of particles were measured for solid-liquid two-phase flow through vertical and horizontal tubes by a conventional photographic method, and through vertical tubes by two newly developed laser methods. Solid materials used were ion-exchange resin particles and glass beads with diameters of 321 to 1840 μm and densities of 1190 to 2500 kg/m3. Tube diameters were 1.92, 3.00, and 5.42cm.
    The average particle velocity, Up, calculated by the local values of particle concentration and velocity, was correlated with modified Froude number and particle Reynolds number based on the terminal settling velocity in a stagnant fluid with a standard deviation of 5.1 %: for vertical upflow,
    Up/(Us)av=exp(0.010 Re0.40p)-0.0059 Re0.69p[(Us)2av/{DTg(ρpw-1)}]-1/2
    for horizontal flow,
    Up/(Us)av=exp(0.016 Re0.36p)-0.24 Re0.22p[(Us)2av/{DTg(ρpw-1)}]-1/2
    4<Rep<540, 2<(Us)2av/{DTg(ρpw-1)}<120, md<0.05
    where (Us)av is average slurry velocity, DT is tube diameter, ρp and ρw are particle and liquid density, respectively, and md is delivered concentration of particles.
    The laser methods, one for the local concentration and the other for the local velocity, were successfully adopted as more convenient techniques for getting precise information on the behavior of particles than the conventional photographic method.
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  • R. P. SINGH, K. K. NIGAM, P. MISHRA
    1980 Volume 13 Issue 5 Pages 349-353
    Published: October 20, 1980
    Released: April 03, 2006
    JOURNALS FREE ACCESS
    Turbulent flow velocity profiles for the inner and outer flow regions of annul! are proposed. Theoretical expressions for friction factors and entrance region pressure drops are developed and are further extended to the limiting cases of pipes and parallel plates. Experimental data are found to be in good agreement with theoretical results.
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  • AKIRA HIRATA, YOSHIZO SUZUKI
    1980 Volume 13 Issue 5 Pages 354-360
    Published: October 20, 1980
    Released: April 03, 2006
    JOURNALS FREE ACCESS
    A theoretical study was made of mass transfer in a laminar boundary layer through a mobile interface with high mass flux condition. The laminar boundary momentum and diffusion equations are solved numerically with Blasius-type similar transformations. The numerical results are obtained for mass transfer rates by taking account of the diffusional flow due to rapid mass transfer and interfacial velocity due to motion of interface simultaneously. Mass transfer rates are given as function of transfer number B (a dimensionless driving force of mass transfer to be related to diffusional flow), interfacial velocity parameter us/U and Schmidt number. The results show that the interfacial velocity increases the mass transfer rates in the case of high mass flux as well as for low mass flux. This effect is very important in the high-Schmidt number region. The previous theories of high mass flux phenomena with fixed interface can be applied to high mass flux mass transfer with mobile interface as long as the effect of the interfacial velocity, in increasing the mass transfer rates, is considered.
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  • NOBUYUKI IMAISHI, KATSUHIKO FUJINAWA, TEIRIKI TADAKI
    1980 Volume 13 Issue 5 Pages 360-365
    Published: October 20, 1980
    Released: April 03, 2006
    JOURNALS FREE ACCESS
    Condition for the onset of interfacial turbulence in mass transfer is investigated by a linear stability analysis. In a previous paper, it was revealed that inclusion of the Rayleigh effect as well as the Marangoni effect into analysis alters the stability limit and removes the contradiction between many experimental results and the Sternling and Scriven criteria of stability.
    In this paper, the analysis is further extended to include oscillatory instability, which was neglected in the previous analysis.
    The results show that oscillatory instability takes an important role in the onset of instabilities, and also that oscillatory instability always takes place when the destabilizing Rayleigh effect and the stabilizing Marangoni effect are competing.
    It is suggested that the oscillatory instability of this kind may be correlated to the onset of violent interfacial turbulence or eruption.
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  • HIDEHARU HIROSUE
    1980 Volume 13 Issue 5 Pages 365-371
    Published: October 20, 1980
    Released: April 03, 2006
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    For the purpose of making clear the mechanism involved in the axial mixing of particles in rotary dryers and coolers, the axial mixing of particles in batch systems was measured.
    The diffusion model has been applied to the axial mixing of particles in batch and continuous systems and the influence of the operating variables on the diffusion coefficient in batch systems and on the axial dispersion coefficient in continuous systems has been examined.
    As a result, it is found that the influence of the operating variables on both the coefficients is essentially the same and that the ratio of diffusion coefficient to axial dispersion coefficient is approximately equal to 0.7 under the same experimental conditions. This result indicates that as the axial mixing of particles in the batch system is considered to be due to collision and bounce between the particles falling from the flights and the bare wall, the lifting flights and the particles deposited in the lower part of the dryer collision and bounce may be a major mechanism involved in the axial mixing of particles in continuous rotary dryers and coolers.
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  • N. S. TAVARE, M. R. CHIVATE
    1980 Volume 13 Issue 5 Pages 371-379
    Published: October 20, 1980
    Released: April 03, 2006
    JOURNALS FREE ACCESS
    The analysis of a batch dilution crystallizer is presented for different modes of operation using the Bransom crystal growth rate model and power law nucleation rate model. This analysis is used for potassium sulphate crystallization from aqueous solution using ethanol as a diluent. The process configuration is analysed over a wide range of variables in each mode of operation and suitable value of the operating variable is suggested for better and safer performance of a given batch dilution crystallizer.
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  • FRANK M. TILLER, O. V. ANANTHARAMAKRISHNAN
    1980 Volume 13 Issue 5 Pages 380-385
    Published: October 20, 1980
    Released: April 03, 2006
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    Filtration characteristics of slurries with varying concentration under constant applied pressure were studied. The problem was investigated by considering addition of feed slurry to a filtration chamber initially containing particulate free liquid.
    Theoretical analyses of two limiting cases of perfect displacement and complete mixing are presented. Constant pressure filtration experiments on Westex talc designed for variable slurry concentration under complete mixing conditions confirm theoretical predictions.
    Analyses of experimental data ignoring the variations in slurry concentration would be incorrect and would lead to erroneous results. Based on theoretical conclusions, a method of analysing experimental data under such conditions is presented.
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  • YUJI SATO, YASUHIRO MURAKAMI, TSUTOMU HIROSE, YOSHIFUMI URYU, Kon HIRA ...
    1980 Volume 13 Issue 5 Pages 385-389
    Published: October 20, 1980
    Released: April 03, 2006
    JOURNALS FREE ACCESS
    Dilute emulsified particles (C≈300g⋅m-3, DP≈8μm) of heavy oil A were removed in a 65 mm-diameter, 0.32 m-deep column with a solution of pH 4 which minimized double-layer repulsion.
    Firstly, flotation by bubbling through glass frits of three different pore sizes shows that the removal rate is proportional to the oil concentration to the first order at low gas velocity (0.01≤ Ug≤0.05cm⋅s-1) and to the second order at high gas velocity (0.1≤Ug≤3cm⋅s-1). This fact implies that the predominant rate step is oil particle-bubble collision in the former region and particle-particle collision in the latter. Mechanical agitation by a paddle gives the same removal rate as bubbling in the high gas velocity region when the power consumption per unit volume is the same. This fact implies that the role of bubbling there is to give adequate turbulence to the liquid.
    Secondly, the bubble diameter was changed from 40 pm to 2 mm under the mechanism of bubbleparticle collision by electrolysis, dissolved and bubbling air flotation. With increasing bubble diameter, the collection efficiency decreases rapidly (≈to the -2 power) for small bubbles and much more gradually for large bubbles. This trend coincides with the existing and proposed trajectory theories.
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  • HIROSHI YUKAWA, KAZUMASA KOBAYASHI, MASARU HAKODA
    1980 Volume 13 Issue 5 Pages 390-396
    Published: October 20, 1980
    Released: April 03, 2006
    JOURNALS FREE ACCESS
    It was found in our previous paper that an electrokinetic filtration could considerably increase the filtration flow rate in comparison with that of the conventional filtration, because electrophoresis in the slurry and electroosmosis in the cake were caused by the electric field. This method is especially applicable to the filtration of slurries such as bentonite slurry, which is difficult to filter by mechanical pressure because of gelatinous cake formation. Tn this experiment, an electrokinetic filter made by modifying an Oliver filter was used and its performance was investigated. Calcium carbonate, white clay and bentonite were used as suspended particles. As a result, it was confirmed that electrokinetic filtration is applicable to practical filtration and that the equation for the electrokinetic filtration proposed in this paper is applicable to the design of a practical filtration process.
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  • MOMPEI SHIRATO, TOSHIRO MURASE, KUNIO ATSUMI
    1980 Volume 13 Issue 5 Pages 397-401
    Published: October 20, 1980
    Released: April 03, 2006
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    In industrial calculations for design of expression equipment, application of the rather complicated analytical solutions of the so-called consolidation equation may lead us to some difficulties, although the solutions can serve as a predominant basis for a firmer understanding of the mechanism of deliquoring of solid-liquid mixtures by compression.
    To afford a useful mathematical tool for industrial analysis of constant-pressure expression of filter cakes with inhomogeneous void ratio distribution, the simplified equation previously presented for constant-pressure expression of homogeneous semisolid materials is extended. The calculated results by using the simplified computational method presented in this paper have shown reasonable agreement with experimental results. It has been also demonstrated that the experimental values of both the modified consolidation coefficient C''e and the consolidation behavior index v can easily be determined by graphical methods. It should be noted that the v-value for filter cakes determined by the simplified computational method may tend to become larger than those for homogeneous semisolid materials.
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  • HIROMOTO USUI, YUJI SANO
    1980 Volume 13 Issue 5 Pages 401-404
    Published: October 20, 1980
    Released: April 03, 2006
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  • KATSUTOSHI INOUE, HIRONORI AMANO, ISSEI NAKAMORI
    1980 Volume 13 Issue 5 Pages 405-406
    Published: October 20, 1980
    Released: April 03, 2006
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  • HUNG-SHAN WENG
    1980 Volume 13 Issue 5 Pages 407-409
    Published: October 20, 1980
    Released: April 03, 2006
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  • TADASHI CHIDA, TEIRIKI TADAKI
    1980 Volume 13 Issue 5 Pages 410-411
    Published: October 20, 1980
    Released: April 03, 2006
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  • TATSUO KANKI, SATORU IUCHI
    1980 Volume 13 Issue 5 Pages 412-414
    Published: October 20, 1980
    Released: April 03, 2006
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  • HIROSHI YOSHIDA, TADASHI SHINKAWA, HIROSHI YUKAWA
    1980 Volume 13 Issue 5 Pages 414-417
    Published: October 20, 1980
    Released: April 03, 2006
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  • TETSUO AKIYAMA, TAKAHIRO NISHIOKA, HIROMI BABA, SATORU MITSUMORI, Kozo ...
    1980 Volume 13 Issue 5 Pages 417-419
    Published: October 20, 1980
    Released: April 03, 2006
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