KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 27 , Issue 4
Showing 1-22 articles out of 22 articles from the selected issue
Special Issue [The Latest Frontiers of Bubble Columns and Slurry Bubble Columns]
  • Eiichi Kojima
    2001 Volume 27 Issue 4 Pages 419-429
    Published: July 20, 2001
    Released: December 30, 2008
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    Bubble column and airlift bioreactors are widely used in a broad spectrum of cultivation because of higher mass transfer rates, lower power input, relatively low shear stress to the cells, and simplicity of design. This paper reviews recent reports in reference to the relationship between hydrodynamics and performance of bioreactors such as product formation, biomass production, and decomposition of pollutants. In the culture systems of microorganisms, topics such as the relation between performance of aerated reactors and process parameters in large-scale reactors including pilot-scale units, effective production systems using pellet-shaped or immobilized cells, and cultivation of microalgae are presented. Product formation by plant cells in suspended callus culture or in differentiated cells such as hairy roots are described. Damage to animal cells suspended or grown on microcarriers is also reviewed, as well as the effect of additives and oxygen supply. Regarding wastewater treatment, a hydrodynamic model for the biofilm airlift suspension reactor, the mechanisms of biofilm detachment, and treatment systems of toxic or refractory pollutants are discussed.
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  • Yoshiyuki Bando
    2001 Volume 27 Issue 4 Pages 430-442
    Published: July 20, 2001
    Released: December 30, 2008
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    The flow characteristics in bubble column with draft tube were studied from a viewpoint of equipment dimension. Especially, the effect of length of each part such as draft tube length, upper and lower clearances, was examined. The effect of column aspect ratio (column height/column diameter) on the liquid mixing time and the effect of distance between the upper end of draft tube and the liquid surface at aeration on the liquid circulation flow rate were clarified. The relation between the circulation flow rates of liquid and gas was obtained.
    The results in bubble columns with contrived draft tube were shown. In the bubble column with perforated draft tube, the performances of gas-liquid mass transfer and liquid mixing were greatly improved because of the unique flow behavior. A series of studies such as combinations with packing and countercurrent bubble column, were shown. The application studies in viscous liquid and wastewater treatment were described.
    The effect of equipment dimension on the flow characteristics in three-phase fluidized bed withdraft tube was discussed.
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  • Koichi Terasaka, Hideki Tsuge
    2001 Volume 27 Issue 4 Pages 443-448
    Published: July 20, 2001
    Released: December 30, 2008
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    To promote liquid circulation in an airlift bubble column with an inner draft tube, a propeller was set in inside the draft tube. By revolving the propeller, the liquid is forced to flow upward in the draft tube and to flow down in the annulus. For a bubble column of constant diameter and a highly viscous liquid, the effects of the diameter of the draft tube and the revolution rate of the propeller on gas holdup, liquid circulation rate and volumetric mass transfer coefficient were investigated experimentally.
    In the pressure drop throughout the circulation of highly viscous liquid in the internal airlift bubble column, the pressure drops at the walls of the draft tube and in the annulus were much larger than the other pressure drops.
    By the combination of previous dimensionless empirical equations, the averaged volume tric masstransfer coefficient in the whole bubble column was estimated relatively well.
    The additive liquid stream generated by the revolution of the propeller promoted the increase of gas holdup in the annulus and the increase of volumetric mass transfer coefficient.
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  • Keiji Yasuda, Masayoshi Oga, Misako Tachi, Lei Rong, Yoshiyuki Bando, ...
    2001 Volume 27 Issue 4 Pages 449-453
    Published: July 20, 2001
    Released: December 30, 2008
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    For the treatment of including refractory material in wastewater, an airlift ultrasonic reactor was proposed. The reactor was a bubble column with a draft tube and an ultrasonic oscillator attached at the column bottom. The gas was sparged into the draft tube or into the annulus between column and draft tube. The gas velocity was changed and the apparent decomposition reaction rate constant of tetraphenylporhyrine tetrasulfonic acid was measured. Regardless of the mode of sparging gas, the apparent reaction rate constant increased with increasing gas velocity.
    To examine the effects of liquid and gas velocities on the apparent reaction rate constant in the airlift ultrasonic reactor, a tubular reactor with an ultrasonic oscillator was used. In the tubular reactor, the liquid and gas velocities were independently controlled, and the apparent reaction rate constant was measured. The apparent reaction rate constant increased with increasing liquid velocity or with increasing gas holdup. The effects of liquid velocity and gas holdup were expressed by experimental equations. For the apparent reaction rate constants in airlift ultrasonic reactor, the results calculated from experimental equations agreed well with the measured data within an error of ±30%.
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  • Masayuki Toda, Shinobu Yoshikawa, Naoki Mogi, Jun Ikeda
    2001 Volume 27 Issue 4 Pages 454-460
    Published: July 20, 2001
    Released: December 30, 2008
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    In a draft tube gas-liquid-solid spouted vessel, the average gas holdups and annulus liquid circulation velocities were measured over a wide range of operating conditions, and the flow patterns were observed. The hydrodynamic characteristics obtained for the gas-liquid-solid three-phase system were also compared with those for the gas-liquid two-phase system. For low gas and liquid flow rates, gas holdups were strongly affected by the solid particles, and the gas holdups in the gas-liquid-solid three-phase system were always higher than those in the gas-liquid two-phase system. Experimental equations were also proposed to express the gas holdups in the whole range of gas and liquid flow rates. Annulus liquid circulation velocities obtained for the low liquid flow rate were greatly reduced by the solid particle beds on the bottom of a column. However, after all solid particles began to circulate in the column, the behaviors of annulus circulation velocities were found to be very similar to those in a draft tube gas-liquid spouted vessel.
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  • Tatsuya Hasegawa, Wei Chen, Koji Kuramoto, Ryuji Kikuchi, Atsushi Tsut ...
    2001 Volume 27 Issue 4 Pages 461-465
    Published: July 20, 2001
    Released: December 30, 2008
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    The instantaneous local heat transfer rates in a 2-D bubble column were measured by using a hot wire probe. An artificial neural network (ANN) was applied to correlate the fluctuation of heat transfer rates with dynamic motions of bubble and liquid. The optimal structure of the artificial neural network was determined for the prediction of heat transfer rates. The trained ANN model gives a good prediction of dynamic heat transfer with errors of less than 5%.
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  • Koji Kuramoto, Tatsuya Hasegawa, Atsushi Tsutsumi
    2001 Volume 27 Issue 4 Pages 466-469
    Published: July 20, 2001
    Released: December 30, 2008
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    To elucidate the microscopic turbulent structure around the rising bubbles in a continuous single-bubble flow system, instantaneous local flow behavior was investigated in conjunction with simultaneous visual observation using a high speed video camera in a two-dimensional column. A hot-wire probe with a filament of tungsten wire having a diameter of 10 mm allowed the local convective behavior around the rising bubbles to be measured in terms of the heat transfer rate with high spatio-temporal resolution. Time series obtained with the hot-wire probe was synchronized with the visual signals to clarify the microscopic flow structure around the rising bubbles. Local turbulence was promoted when the bubble is about to either make or break contact with the tip the of the hot-wire probe. The heat transfer rate exhibited a sharp peak in the stable wake region, which contains an energetic turbulent structure providing highly chaotic motions of liquid phase generated by the oscillations in bubble shape andmotions.
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  • Katsuhiko Muroyama, Tadayoshi Yoshikawa, Yuya Goto, Teruhiro Ariyoshi
    2001 Volume 27 Issue 4 Pages 470-476
    Published: July 20, 2001
    Released: December 30, 2008
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    In the present study, the cylinder surface-to-liquid mass transfer coefficient was measured in three-phase fluidized beds of 82 mm O. D., with glass beads (average diameter; 2.2-5.2 mm) and aluminabeads (average diameter; 0.75-3.0 mm) as fluidized particles, using the limiting current method. One of the cylinder electrodes used was vertically inserted along the centerline of the fluidized beds and the other was horizontally set in the transverse direction of the column cross section. The outside diameter of the two electrodes was commonly 20 mm. The effect of operating conditions such as liquid velocity, gas velocity and particle diameter on the mass transfer coefficient was investigated.
    Unified correlations were developed from the measured surface-to-liquid mass transfer coefficients for the liquid-solid and three-phase fluidized beds in terms of the modified Colburn j-factor, or in terms of the specific power group based on the energy dissipation rate per unit mass of liquid. The presence of an analogy was confirmed between the mass transfer and heat transfer through the liquid film on thecylinder surface.
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  • Yoshiyuki Bando, Makoto Chaya, Keiji Yasuda, Yukio Sakurai, Masaaki Na ...
    2001 Volume 27 Issue 4 Pages 477-479
    Published: July 20, 2001
    Released: December 30, 2008
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    The effect of oil dispersion on the flow characteristics in bubble column is experimentally examined. The kind and concentration of oil are changed, and oil is dispersed in tap water. The flow pattern of bubbles and the oil dispersion are observed, and the distribution of oil droplet, the gas holdup and the volumetric coefficient are measured.
    The flow characteristics in bubble column are changed due to small oil droplets. The gas holdupbecomes higher, but the volumetric coefficient becomes lower than those in tap water. From these, it is concluded that the mass transfer coefficient becomes lower in the oil dispersion system.
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  • Hiroshi Ishiyama, Haruki Kaneoka, Jun Sawai, Hiromitsu Kojima
    2001 Volume 27 Issue 4 Pages 480-483
    Published: July 20, 2001
    Released: December 30, 2008
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    The effect of pressure on gas holdup was investigated experimentally with gas-liquid systems, of nitrogen-water, and carbon dioxide-water, in a bubble column with diameter of 45 mm. Single nozzles of 1.4, and 4.0 mm in diameter were used as gas disperser. When the 4.0 mm nozzle was used, no effect of pressure on gas holdup was observed. When single nozzle of 1.4 mm with nitrogen as the gas phase, gas holdup increased with pressure. But when carbon dioxide was used as the gas phase, gas holdupshowed a maximum at pressure of 0.6 MPa. The gas holdup at 1.1 MPa was approximately the samevalue as that at atmospheric pressure. To explain these phenomena by the behavior of bubbles in thecolumn, bubble size near the wall and bubble frequency at the center of column were measured.
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Themodynamics, Physical Properties and Molecular Simulation
  • Kazuo Kondo, Yusuke Sekiya, Keisuke Fukui, Zennosuke Tanaka
    Type: Technical Research Paper
    Subject area: Themodynamics, Physical Properties and Molecular Simulation
    2001 Volume 27 Issue 4 Pages 484-486
    Published: July 20, 2001
    Released: December 30, 2008
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    Electrodeposited via-posts are important elements in wafer level CSP. Cross sections of these via-posts were observed for the via-posts with less than 100 μm cathode length. Heights of via-posts becomenon-uniform with the narrower via-post pitches. Via-posts become the higher for lower portion of electrode and lower for the upper portion of electrode. The uniformity increases for wider via-post pitches. The uniform height via-posts form via-post pitch of for longer than 700 μm at 100 μm cathode length. Uniform height forms for pitch of longer than 400 μm at 75 μm cathode length, longer than 250μm at 50 μm cathode length and longer than 100 μm at 25 μm cathode length. The solution becomes dilute because of consumption of copper ion at the cathode via. This dilute solution emerges from the via and becomes upper stream flow, which travels along the resist surface and flows into the vias atupper portion of the electrode. The upper stream flow mixes with bulk electrolyte along the resist surface and recovers its concentration. With longer resist surface distance, the flow mixes more with bulk electrolyte and increases recovery. This concentration recovery along the resist surface causes the height of via-posts as uniform.
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  • Masayuki Aoshima, Akira Satoh, Geoff N. Coverdale, Roy W. Chantrell
    Type: Note
    Subject area: Themodynamics, Physical Properties and Molecular Simulation
    2001 Volume 27 Issue 4 Pages 528-531
    Published: July 20, 2001
    Released: December 30, 2008
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    We have investigated the orientational distribution of a dilute colloidal dispersion of ferromagnetic spherocylinder particles for the case of a steady simple shear flow in a magnetic field parallel to the angular velocity vector of the shear flow. The results obtained are summarized as follows. When the flow field is dominant compared with the Brownian motion and the magnetic interactions, the particles rotate in the plane perpendicular to the magnetic field direction. As the magnetic field increases, the particles incline towards the magnetic direction, so that the viscosity is independent of the magnetic field and is zero.
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Transport Phenomena, Fluid Mechanics and Mixing
Catalysis, Kinetics and Reactor Design
  • Takahiro Shimizu, Osamu Okuma
    Type: Fundamental Research Paper
    Subject area: Catalysis, Kinetics and Reactor Design
    2001 Volume 27 Issue 4 Pages 502-509
    Published: July 20, 2001
    Released: December 30, 2008
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    The reactivity of brown coal and upgraded brown coal (UBC), produced by coal-oil slurryde watering process, for low-temperature oxidation was investigated in comparison with steaming coals using kinetic analysis of O2 adsorption and weight variation during oxidation. The kinetic analysis was conducted by assuming first-order reactions of O2 adsorption to form oxides and of decompositions ofthe original and oxidized components of the coal. The natural logarithm of each calculated rate constant (k) for three such reaction paths was found to be a linear function of reciprocal temperature. The rateconstants of O2 adsorption obtained by different methods were plotted on the same line. These results indicate that low temperature oxidation process of the coals is expressed by such reaction scheme and rate constants. It is also recognized that O2 adsorption is affected by the pore structure of coals, and the rates of O2 adsorption and pyrolysis of brown coal are much larger than those of the steaming coals at lower temperature. The slurry dewatering process was found to reduce the susceptibility to spontaneous heating of dried brown coal because the reactivity of UBC was smaller than that of the brown coal dried in vacuo.
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  • Shi-Ying Lin, Yoshizo Suzuki, Hiroyuki Hatano
    Type: Note
    Subject area: Catalysis, Kinetics and Reactor Design
    2001 Volume 27 Issue 4 Pages 520-523
    Published: July 20, 2001
    Released: December 30, 2008
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    Char combustion rate in elevated pressure conditions was examined experimentally and theoreti-cally by changing factors such as particle size, gas flow rate, and oxygen concentration. These factorswere found to influence rate control regimes and change the pattern of pressure effect on rate. Forinstance, at same temperature, decrease in the particle size of char enhanced the effect of pressure onchar combustion rate.
    Mass flow rate, υgρg, or flow rate at standard temperature and pressure, υg,o, was used to evaluatethe diffusion resistance of the gas film. It was found that, char combustion rate increase with increasingυgρg or υg,o.
    Combustion rate can be expressed by using the oxygen concentration at standard temperature andpressure, Co, or the partial pressure of oxygen, Po2, as the gas reactant term in the rate equation.However, explanation of pressure effect on combustion rate was greatly different in both expressions.
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Separations
  • Masaru Fujiwara, Naotake Katoh
    Type: Note
    Subject area: Separations
    2001 Volume 27 Issue 4 Pages 510-512
    Published: July 20, 2001
    Released: December 30, 2008
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    To obtain a unimodal crystal size distribution, linear cooling of a batch crystallizer was experimentally examined. Sodium sulfate, which has a relatively large heat of crystallization, was crystallized.
    The condition for batch crystallizer operation within the metastable region was derived: the product of temperature derivative of solute saturation concentration and cooling rate must be less thana certain value.
    Experiments were carried out with cooling rate satisfying the operation condition. A nearly uni-modal product of sodium sulfate was obtained.
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Particle Technology and Fluidization
  • Junji Shibata, Katsuya Fujii, Kenichi Horai, Hideki Yamamoto
    Type: Fundamental Research Paper
    Subject area: Particle Technology and Fluidization
    2001 Volume 27 Issue 4 Pages 497-501
    Published: July 20, 2001
    Released: December 30, 2008
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    The relation between the flocculation and dispersion of metaloxide powders and the properties of solvents, such as dielectric constant and solubility parameter was investigated for TiO2, Al2O3 and Fe2O3. The median diameter of these metal oxides was measured in many organic solvents, from which theeffect of the solvents on the flocculation and dispersion of metal oxide powders was considered.
    The metal oxide powders of Al2O3, TiO2 and Fe2O3 tend to disperse in a solvent of higher polarity, whereas they are apt to flocculate in a solvent of low dielectric constant, because the Hamaker constant between the particles becomes larger in such a solvent. There are, however, some solvents that do not show these tendencies. It is possible to evaluate the flocculation and dispersion of these metal oxide powders in many solvents by using Hansen's three-dimensional solubility parameters (fp, fd and fh). Foreach metal oxide powder there exists a solvent producing optimal dispersion, and the optimal dispersion point of fp, fd and fh is determined by the combination of metal oxide powder and the solvent.
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  • Takami Kai, Koji Makado, Takeshige Takahashi, Toshio Tsutsui, Koh Sato
    Type: Note
    Subject area: Particle Technology and Fluidization
    2001 Volume 27 Issue 4 Pages 524-527
    Published: July 20, 2001
    Released: December 30, 2008
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    When alumina and FCC catalysts were mixed, the fluidity of the mixture was significantly lowerthan that of each particle type alone. A significant amount of dried particles adhered to the inner wallof a column, and channeling was observed. The main cause of these phenomena was found to besymmetrical electrification due to mutual friction between the two types of particles. This causedagglomeration of particles and the decrease in the fluidization quality. Adding 4 wt% of water to thepores of the particles reduced the influence of the electrostatic force. Increasing the bed temperatureabove 523 K also improved the fluidity of the beds.
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Process System Engineering
Biochemical, Food and Medical
  • Takenori Tanaka, Toshiteru Komatsu, Nobuharu Kotani, Masahito Taya
    Type: Note
    Subject area: Biochemical, Food and Medical
    2001 Volume 27 Issue 4 Pages 517-519
    Published: July 20, 2001
    Released: December 30, 2008
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    The effect of aeration rate on dissolved oxygen concentration in broth, CDO,obS, and specific oxygenconsumption rate, Q, was examined in industrial-scale culture of an alkaline cellulase-producingbacterium. In the two stage culture with fructose addition at a specific aeration velocity, SV=0.0075 s-1,CDO,obS was kept above 2.1 g/m3 throughout the culture period and a fall in the Q value was moderatedin the late stage of the culture. Moreover, DNA concentration in broth measured at the end of the twostage culture was comparable to that from the conventional batch culture at SV=0.006 s-1, indicatingthat cell lysis was suppresed in the two stage culture.
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  • Yoshiaki Shiba, Matabeei Katano, Takayuki Ohshima, Masayuki Sato
    Type: Prompt Paper
    Subject area: Biochemical, Food and Medical
    2001 Volume 27 Issue 4 Pages 532-534
    Published: July 20, 2001
    Released: December 30, 2008
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    The metabolic activity (glucose consumption and lactate production) of L-929 cells in a liquid/liquid interface system (culture medium/fluorocarbon) has been investigated in long-term culture. Thespecific glucose consumption rate and specific lactate production rate at the interface were found to behigher than those at a polystyrene surface. This result can be related to the fact that the cell adhesionat the interface is weaker than that at a polystyrene surface. It was suggested that cell culture at theinterface could be significant in raising yields from animal cell bioreactors.
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Safty, Enviroment and Energy
  • Jiaan Xia, Kiyoshi Noda, Shoji Kagawa
    Type: Fundamental Research Paper
    Subject area: Safty, Enviroment and Energy
    2001 Volume 27 Issue 4 Pages 487-492
    Published: July 20, 2001
    Released: December 30, 2008
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    In a series of studies on the production of activated carbon from the waste material (bagasse) remaining after pressing of sugarcane. We obtained produce activated carbon with a specific surface area of 1,096 x 103 m2/kg by treating the bagasse under the following conditions : activation temperature, 1,073 K, rate of temperature-increase, 5 K/min, retention time, 1.0 hour; and the amount of water, 6 kg/kg-bagasse. Next, an attempt to increase the hardness of the activated carbon yielded material with a hardness level of about 1/3 that of commercially available coconut-shell activated carbon. The adsorption equilibrium of the hardened activated carbon, for 13 different organic compounds in single-solute aqueous solutions at 298 K was then measured in a concentration range of 0.01 to 500 mol/m3. The amount of solute adsirbed by this activated carbon at each concentration was found to be the same as or higher than that of the ordinary CAL activated carbon. With respect to the obtained adsorption equilibrium, the Langmuir equation was solved and the result was found to fit to the equation.
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