JOURNAL OF CHEMICAL ENGINEERING OF JAPAN
Print ISSN : 0021-9592
Volume 20 , Issue 1
Showing 1-21 articles out of 21 articles from the selected issue
  • MOMPEI SHIRATO, MASASHI IWATA, MASAHIRO WAKITA, TOSHIRO MURASE, NIICHI ...
    1987 Volume 20 Issue 1 Pages 1-6
    Published: February 20, 1987
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    In a batch wise constant-rate expression process, a material is compressed at a constant deliquoring rate by increasing the expression pressure. When the pressure reaches a specified, predetermined value, the pressure is held constant until the final equilibrium compression is obtained. In this paper, the constant-rate expression process of homogeneous semisolid materials is discussed and a method for analyzing this constant-rate process is presented. The following assumption is made: the internal condition of consoh''dated cake is the same under an instantaneous pressure p in constant-rate operation as under such a pressure p in constant-pressure operation when the same volume of liquid is removed from the same amount of the original materials in both operations. Using this assumption, the changes of sample thickness and the expression pressure in the constant-rate process can be calculated with the analytical equation for the constant-pressure process. A useful graphical method is also shown for determining the change in expression pressure with time.
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  • KENJI OCHI, KAZUO KOJIMA
    1987 Volume 20 Issue 1 Pages 6-10
    Published: February 20, 1987
    Released: April 19, 2006
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    Vapor-liquid equilibrium (VLE) data for a mixture at extreme dilution in the range 10-2 to 10-5 mole fraction are necessary in a high-grade purification by distillation. However, it is difficult to measure the VLE data in such a dilute concentration range by the conventional methods.
    This paper presents a method for measuring the VLE data at extreme dilution using the ebulliometer, by which bubble temperatures of the mixture of charged composition can be accurately measured by taking account of the vapor-phase holdup. This method has been applied to measurement of VLE data for four binary systems of water with alcohols as dilute solutes at 101.325 kPa.
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  • KENJI OKADA, YASUHARU AKAGI
    1987 Volume 20 Issue 1 Pages 11-15
    Published: February 20, 1987
    Released: April 19, 2006
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    A method and an apparatus to measure the ξ-potential of bubbles has been developed. The apparatus is of microelectrophoresis type. Small bubbles of 20-40μm in diameter are generated by pressure reduction of a solution containing dissolved air and are introduced into an electrophoresis cell of 0.972 mm thickness. As the movement of the bubbles is followed over 4 seconds in this arrangement, the measurement error due to the rapid rising of the bubbles can be considerably decreased. The bubbles were positively charged in a cationic surfactant solution of cetyltrimethylammonium bromide (CTAB) and the charge decreased with increasing electrolyte concentration in the solution. In an anionic surfactant solution of sodium dodecyl sulfate (SDS), both the bubbles and oil particles were negatively charged. But, by the addition of Al2(SO4)3, the oil particles maintained their negative charge while the charge of the bubbles was changed to positive. The situation of the attaching of oil particles to bubbles was observed photographically.
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  • HITOSHI FUNAHASHI, MASAO MAEHARA, HISAHARU TAGUCHI, TOSHIOMI YOSHIDA
    1987 Volume 20 Issue 1 Pages 16-22
    Published: February 20, 1987
    Released: April 19, 2006
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    The effects of agitation by a flat-bladed turbine impeller on the microbial production of xanthan gum were studied. The results showed that the intensity of shear flow of an impeller was particularly important compared with other physical factors relevant to agitation. It was also observed in an equipment of defined shear rate that the specific production rate of xanthan gum and the specific oxygen uptake rate were influenced by the shear stress but not by the shear rate. Both of these rates increased with increasing shear stress in the range of 0-40 Pa, beyond which they were constant. Increase in glucose concentration, as the driving force of glucose transfer from the medium into the cells, resulted in increase of the specific production rate of xanthan gum. These results suggest that the shear stress was particularly important for xanthan gum production and that the microbial production of xanthan gum might be limited by the mass transfer of the materials from the medium into the cells at low shear stress.
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  • TOSHITAKA FUNAZUKURI, TETSUYA TAKANASHI, NORIAKI WAKAO
    1987 Volume 20 Issue 1 Pages 23-27
    Published: February 20, 1987
    Released: April 19, 2006
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    Samples from a used automotive tire were subjected to subcritical and supercritical extraction with water. Supercritical water was found to be almost as effective as supercritical n-pentane. For a 9-mm cube sample the rate of supercritical extraction with water followed a first-order kinetics with an activation energy of 170kJ/mol. Dynamic TGA data for 0.13-0.35 mm samples showed that pyrolysis at temperatures of 690-730 K had almost the same activation energy as did supercritical extraction with water.
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  • MIKI FUKUMA, KATSUHIKO MUROYAMA, AKIRA YASUNISHI
    1987 Volume 20 Issue 1 Pages 28-33
    Published: February 20, 1987
    Released: April 19, 2006
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    The effects of solid concentration and liquid viscosity on bubble properties such as bubble size and bubble rising velocity were measured with a dual-electroresistivity probe in a slurry bubble column of 0.15m diameter. The behavior of volume-surface mean bubble diameter, dvs, was analyzed.
    By addition of solid particles at small gas velocity, the bubble size distribution shifted to a large-size region and the bubble velocity distribution shifted to a large-velocity region. At the same time, the flow pattern changed from homogeneous flow to heterogeneous flow. The effect of solid particles on bubble size, however, became small as the particle diameter decreased or the liquid viscosity increased.
    The following equation was derived to estimate dvs.
    dvs=0.59(VDg)2/g
    where VD is the drift flux of gas, εg is the cross-sectionally averaged gas holdup and g is the gravitational acceleration.
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  • MASAO SUDOH, HIROSHI KAMEI, SUSUMU NAKAMURA
    1987 Volume 20 Issue 1 Pages 34-40
    Published: February 20, 1987
    Released: April 19, 2006
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    The concentration of cupric ion was studied with a flat-plate dialyzer having a single cation exchange membrane. The exchange equilibrium constants were expressed as a function of the ionic strength of the bulk solution. The flux of osmotic water was linearly proportional to the difference of ionic strength between the feed and the strip solutions. The maximum values of the enrichment ratio obtained experimentally became smaller than those calculated from the relationship of Donnan equilibrium. The experimental changes of enrichment ratio with time, however, agreed well with the values calculated by using the measured values of physical properties of the membrane, self-diffusion coefficients, distribution coefficients of ions, liquid film resistances and the flux of osmotic water.
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  • ISAO KOMASAWA, YASUNOBU MAEKAWA, TSUTAO OTAKE
    1987 Volume 20 Issue 1 Pages 41-46
    Published: February 20, 1987
    Released: April 19, 2006
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    The extraction of cobalt was studied, employing benzene as a diluent to weakly solvate the extractant. In benzene, the extractant needs to surround itself with stabilizing molecules. A simple extraction scheme is presented which assumes that the extraction of cobalt occurs via reaction with the monochloride acid-complex of the extractant, i.e., via the replacement of water and acid in the salt hydration sphere by cobalt ion. The data obtained at acid concentrations of 2-7 mol/l and loading ratios up to maximum were analysed according to the scheme. Three species of the extract were considered. The fraction of 1:1 complex, R3R''NCL·COCL2, was very close to 1 at very low loading. The fraction of monomeric 2:1 complex, (R3R''NCL)2·COCL2, was less than 0.02 over the whole range observed, while the dimeric species, {R3R''NCL·COCL2}2, increased with loading ratio of the extractant. Self-association of the extract entity seems to be needed to stabilize itself in the relatively inert diluent.
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  • ISAO KOMASAWA, TSUTAO OTAKE
    1987 Volume 20 Issue 1 Pages 46-51
    Published: February 20, 1987
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    The extraction of cobalt was studied, using solvating effect diluents such as chloroform and 2-ethylhexyl alcohol, and was compared with results obtained previously for benzene diluent. The solvating effect diluent causes a decrease in the requirement for water and acid as stabilizing molecules for the extractant, and thus prevent water and acid from taking part in the mechanism of cobalt extraction. Aggregation of the extracted cobalt species is also interfered with in the diluent. These effects simplify the mechanism of cobalt extraction. The principal effect is, however, to reduce the extraction performance of the extractant due to stabilization with the diluent. Actually, the extractant is stabilized by forming a bisolvate with alcohol molecules. The extraction equilibrium formulation was established for each diluent, covering a wide range of conditions. The extracted species were monomeric 2:1 complex, (R3R''NCL)2·COCL2, for chloroform diluent, and monomeric 2:1 and 1:1 complexes, (R3R''NCL)2·COCL2 and R3R''NCL·COCL2, for alcohol diluent.
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  • HAJIME UNNO, KAZUO TAGUCHI, TAKASHI AKEHATA
    1987 Volume 20 Issue 1 Pages 52-57
    Published: February 20, 1987
    Released: April 19, 2006
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    Permeation of liquid through a membrane unit of (poly)tetrafluoroethylene (PTFE) was investigated to analyze the effects of liquid properties and the geometrical properties of the membrane unit on permeation. The liquid permeation rate was expressed by a Darcy-type equaton. The permeability coefficient was greatly affected by the interaction between the liquid and the membrane material. Moreover, when the exit-side surface of the membrane is exposed to the air, geometrical conditions such as the geometry of the plate which supports the membrane, and the inclination of the membrane surface affect significantly the permeation rate.
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  • MANABU SHIMADA, KIKUO OKUYAMA, YASUO KOUSAKA, KENTARO OHSHIMA
    1987 Volume 20 Issue 1 Pages 57-64
    Published: February 20, 1987
    Released: April 19, 2006
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    The diffusive deposition of aerosol particles onto a rough wall in a turbulent flow field has been experimentally studied, using a stirred tank having a sand-roughened inside wall and uncharged monodisperse particles of 0.01-0.2 μm diameter. The experimental results showed that the deposition rate of particles onto the rough surface is enhanced, as the roughness increases, compared with that onto a smooth surface. The enhancement depends upon size of particles, intensity of turbulence and roughness of the wall, and is found to be significant when particle size and turbulent intensity are large. To explain the mechanism of the deposition, a model in which the existence of a particle-free layer above the bottom of the roughened wall is assumed is presented. The enhancement of the deposition obtained in the experiments can be described well by this model, and the enhancement results mainly from turbulent diffusion near the wall.
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  • HIROMOTO USUI, YOSHITO YAMASAKI, YUJI SANO
    1987 Volume 20 Issue 1 Pages 65-70
    Published: February 20, 1987
    Released: April 19, 2006
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    The laminar heat transfer coefficient for a round tube flow of highly loaded coal-water mixture (CWM) was measured in a pressurized recirculating flow loop. It was found that when the slurry temperature was less than 100°C the heat transfer coefficient for CWM could be estimated by a usual Newtonian correlation within experimental error, and that the viscosity change of CWM with temperature could be evaluated by the viscosity change of the solvent. On the other hand, when the slurry temperature exceeded 100°C, both the augmentation of heat transfer coefficient and viscosity of CWM were observed. The augmentation of heat transfer coefficient was semiquantitatively explained by the increase in Bingham plasticity of CWM at higher temperature range.
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  • KUNIO KATAOKA, RYUICHI SAHARA, HISASHI ASE, TAKAO HARADA
    1987 Volume 20 Issue 1 Pages 71-76
    Published: February 20, 1987
    Released: April 19, 2006
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    A large-scale coherent structure responsible for the enhancement of stagnation-point heat transfer was successfully determined using a statistical analysis with conditional sampling in an impinging round jet. It was found that the optimal nozzle-to-plate spacing for maximal stagnation-point heat transfer is identical with the jet development length for a strong turbulent stream carrying large-scale energy-containing eddies. A physical model of heat transfer enhancement was experimentally derived from the viewpoint of turbulent surface-renewal induced by large-scale eddies impinging on the stagnation-point boundary layer. It was found that the effect of heat transfer enhancement is a function of the proposed surface-renewal parameter consisting of the characteristic turbulence intensity and frequency of the large-scale eddies.
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  • KIYOSHI IKEMIZU, SHIGEHARU MOROOKA, YASUO KATO
    1987 Volume 20 Issue 1 Pages 77-81
    Published: February 20, 1987
    Released: April 19, 2006
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    The combination of ozone and UV radiation is useful in removing refractory compounds dissolved in water. In this paper, the decomposition of ozone with UV radiation was investigated by using a rectangular flow reactor equipped with transparent quartz walls. The decomposition rate of ozone in water was proportional to the UV irradiance and the ozone concentration. The dependence on OH- ion concentration was very weak compared to decomposition without UV radiation. Data were correlated with an experimental equation which was applicable in the pH range of 2-9.
    A simulation of ozone utilization in a model reactor indicates that unnecessarily intensive UV radiation destroys ozone in the gas phase before it is transferred into the liquid phase. This loss decreases the amount of ozone decomposed in the liquid phase and hence hinders the ozonation of dissolved pollutants. Ozone absorption and UV radiation have to be carried out in different parts of the reactor.
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  • MASABUMI NISHIKAWA, FUYUHIKO MORI, SHIGEO FUJIEDA
    1987 Volume 20 Issue 1 Pages 82-88
    Published: February 20, 1987
    Released: April 19, 2006
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    When two immiscible liquids are agitated, a dispersion is formed in which continuous breakup and coalescence of drops occur, and a dynamic equilibrium is attained between breakup and coalescence after a certain time. Effects of the volume fraction of dispersed phase, viscosity of liquid, impeller speed and impeller-to-vessel diameter ratio on the average drop size of a dispersion in a mixing vessel are discussed and correlative equations are proposed. It is also found that the dominant process in deciding average drop sizes in a mixing vessel changes from breakup to coalescence when the average energy dissipation rate or the volumetric fraction of dispersed phase is increased.
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  • TAKAO TSUKADA, MASAKAZU SATO, NOBUYUKI IMAISHI, MITSUNORI HOZAWA, KATS ...
    1987 Volume 20 Issue 1 Pages 88-93
    Published: February 20, 1987
    Released: April 19, 2006
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    The damping oscillation of a hanging drop on a nozzle in the air was studied theoretically and experimentally. In the experiments, an elongated drop on a brass nozzle by electrostatic force was made to oscillate by removing the electric field instantaneously and the subsequent drop motion was recorded by a high-speed camera. In the theoretical study, the time-dependent drop shape and flow inside the drop were simulated numerically by use of the finite element method. It was found that the experimental results of oscillatory behavior for a hanging drop of aqueous glycerin solution were in good agreement with the calculated ones and that the frequency of oscillation was affected by drop volume, surface tension and nozzle size.
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  • AKIRA OHKAWA, OSAMU MATSUBARA, NOBUYUKI SAKAL, KAZUO ENDOH
    1987 Volume 20 Issue 1 Pages 94-95
    Published: February 20, 1987
    Released: April 19, 2006
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  • YASUO HATATE, HIROSHI HAMADA, ATSUSHI IKARI, FUMIYUKI NAKASHIO
    1987 Volume 20 Issue 1 Pages 96-98
    Published: February 20, 1987
    Released: April 19, 2006
    JOURNALS FREE ACCESS
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  • AKIRA OHKAWA, YOSHIYUKI KAWAI, DAISUKE KUSABIRAKI, NOBUYUKI SAKAI, KAZ ...
    1987 Volume 20 Issue 1 Pages 99-101
    Published: February 20, 1987
    Released: April 19, 2006
    JOURNALS FREE ACCESS
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  • TATSUO NISHIMURA, TADASHI YOSHINO, YUJI KAWAMURA
    1987 Volume 20 Issue 1 Pages 102-104
    Published: February 20, 1987
    Released: April 19, 2006
    JOURNALS FREE ACCESS
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  • HIROMITSU KOJIMA, YASUKO UCHIDA, TAKASHI OHSAWA, AKIHIRO IGUCHI
    1987 Volume 20 Issue 1 Pages 104-106
    Published: February 20, 1987
    Released: April 19, 2006
    JOURNALS FREE ACCESS
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