KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 17 , Issue 1
Showing 1-35 articles out of 35 articles from the selected issue
  • Noriyuki Yamada, Eiichi Abe, Hideharu Hirosue
    1991 Volume 17 Issue 1 Pages 1-8
    Published: January 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Change in density distribution with time caused by segregation in the vertical direction of a continuous fluidized bed was investigated theoretically and experimentally. A model for simulation was constructed, basically by a mass balance. In the model it was assumed that the sample was segregated at the moment when it was fed into the bed and that the light particles were discharged in a constant thin layer from the upper outlet of the bed and the heavy particles from the lower outlet according to a partition function determined experimentally. The experiments were carried out by using fly ash as model particles having a continuous density distribution owing to unburned carbon content. The density distribution in the fluidized bed varied with the ratio of the discharge rate from the lower outlet to the feed rate. Steady state was achieved in a period five times the mean residence time of particles. Calculated results of the variation of density distribution with time were in reasonably good agreement with the experimental ones.
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  • Naoki Furukawa, Wataru Okada
    1991 Volume 17 Issue 1 Pages 9-14
    Published: January 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The neutralization rate of fatty acid to calcium fatty acid in a coagulation particle using calcium hydroxide solution was studied. The coagulation particles were made by the seed coagulation method, using hydrochloric acid solution as the coagulant.
    The following results were obtained.
    (1) A model of the neutralization rate in a particle was proposed, based upon the unreacted core model in which the rate-controlling step was the diffusion of the hydroxyl ion in a particle.
    (2) To design the neutralization reactor, relation between the conversion X [-] and time t [s] can be simulated when the hydroxyl ion diffusion coefficient D [m2·s-1] is obtained in neutralizing experiments, using the following equation provided that the model density of fatty acid ρ [mol·kg-1], radius of particle R [m] and neutralizing condition pOH are given.
    tR2· {3-3 (1-X) 2/3-2X} /6·10POH·D
    In this study, the hydroxyl ion diffusion coefficient D was 2.91×10-8 m2·s-1 at 358 K.
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  • Katsuhiko Kanari, Yoshiyuki Abe, Kotaro Tanaka, Yoshio Takahashi, Ryuj ...
    1991 Volume 17 Issue 1 Pages 15-21
    Published: January 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The present paper describes experimental and computer simulation results for horizontal U-tube latent thermal storage units with a eutectic of sodium hydroxidesodium nitrate. Through 1000 melting-freezing (charge-discharge) cycle tests on two 30 kWh scale storage units of bare-tube and finned-tube stypes, the heat transfer characteristics were evaluated. Computer simulations of both types of storage units were performed with a two dimensional model. For the finned-tube type, the effect of fin was included in the effective thermal conductivity of molten salt around the tubes. The calculated results were in good agreement with experimental ones. The heat transfer characteristics were evaluated for various storage units with different parameters such as number of passes, and number of heat transfer pipes.
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  • Atsushi Ikari, Yasuo Hatate, Goh Nishino, Shinya Iiyama, Yukio Hamasak ...
    1991 Volume 17 Issue 1 Pages 22-28
    Published: January 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Distillation experiments with shochu mash were carried out at 12.7kPa and atmospheric pressure by use of a 100-l pot-still fitted with two trays. Distillation curves of ethanol and 18 flavor components were obtained. The effect of the trays was examined by comparing the calculated distillation curves with the experimental ones.
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  • Zen'ichi Yamada, Koichi Ohta, Satoshi Takeuchi, Kenji Suzuki, Toshiaki ...
    1991 Volume 17 Issue 1 Pages 29-34
    Published: January 10, 1991
    Released: November 12, 2009
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    Two kinds of heat-stable antibacterial clay interlayer compounds were prepared by exchanging Na-montmorillonite with cationic ammine complexes of silver and copper. The one contained only silver ions, the other silver and copper ions. The extent of elution of Ag+ from the former antibacterial clay was dependent on the ligand. For the latter, the amount of Ag+ eluted was decreased markedly by adding copper ammine complex. However, it was possible to control the extent of elution of Ag+ by changing the loading amount of copper ammine complex. When the antibacterial clay was mixed with plastics, the concentration of Ag+ eluted from the resultant plastics was also dependent on the kind of antibacterial clay. The antibacterial effect for Staphylococcus aureus was observed by mixing only 1 wt% of the clay with plastics. For Bacillus subtilis, though the antibacterial clay having only Ag+ was effective by mixing its 1 wt%, more than 3wt% was necessary for the clay having Ag+ and Cu2+ cations. The toxicity test using mice and rats was found to be negative, indicating that the toxicity of the antibacterial clay was negligible.
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  • Takashi Mano, Shinjiro Mitsuda, Eitaro Kumazawa, Gosei Kawanishi, Shin ...
    1991 Volume 17 Issue 1 Pages 35-40
    Published: January 10, 1991
    Released: November 12, 2009
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    For the continuous preparation of alginate gel beads coated with polyurethane we used a device consisting of a vessel equipped with a double cylindrical nozzle. Alginate gels were formed in the vessel by introducing cell-alginate mixture into CaCl2 solution. The gels slowly fell to the end of the inner nozzle, where urethane prepolymer (PU) was flowing in the outer nozzle for coating the gels. Addition of alumina powder into the cell-alginate mixture made it easy to prepare the immobilized gel beads on a continuous basis. Furthermore, the alumina caused desirable changes in structure of the gel matrix for growth of mouse hybridoma cells secreting antierythropoietin antibodies. Cell growth depended on characteristics of the PU used. PU with low content of isocyanate as a functional group helped to minimize damage to the cells. In addition, PU with high content of ethylene oxide (91%) was better for cell growth and antibody production than that with less ethylene (57%).
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  • Yasuyuki Watanabe, Tomonari Saito
    1991 Volume 17 Issue 1 Pages 41-47
    Published: January 10, 1991
    Released: November 12, 2009
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    As a step in clarifying the acceleration mechanism of Na3PO4·12H2O crystals for nucleation of NaCH3COO·3H2O melt (m.p. 331K), the composition and growth behavior of Na3PO4 hydrate crystals precipitated in the melt were investigated in detail at temperatures from 343 to 373K. The precipitated crystals were not the original Na3 PO4·12H2O crystals, but were Na3PO4·6H2O crystals at temperatures below 348K and Na3PO4·0.5H2O crystals at temperatures over 353K. At temperatures between 348 and 353K, the first precipitated crystals of hexahydrate gradually dissolved into the NaCH3COO·3H2O melt accompanying the growth of the hemihydrate crystals. Such dehydrating transition from hexahydrate to hemihydrate occurred at temperatures from 30 to 35K below the ordinary transition temperature (383K) in aqueous solution. The transition to the hemihydrate is thought to be related to the appearance of acceleration function for nucleation.
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  • Yasuyuki Watanabe, Tomonari Saito
    1991 Volume 17 Issue 1 Pages 48-53
    Published: January 10, 1991
    Released: November 12, 2009
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    To clarify the activation phenomenon of Na3PO4·12H2O as a nucleation agent, added to a melt of NaCH3COO·3H2O as a heat storage material (m.p. 331K), the nucleation characteristics of such activated samples were investigated in detail at various heating temperatures for activation treatment from 333 to 371K. For samples including an agent crystallized as hexahydrate salt by heating at a temperature lower than 348K, the ratio of the number of samples in which nucleation occurred was about 65% during continuous cooling to room temperature (293K). For the case of the agent crystallized as hemihydrate salt at a temperature beyond 353K, nucleation occurred in all samples up to 325K, which was a temperature 6K lower than the melting point of the heat storage material, and strong nucleation activity was observed. At temperatures from 348 to 353K, the nucleation activity became strong by change of the agent's crystal structure from hexahydrate to hemihydrate, due to the temperature elevation. However, the nucleation agent began to lose its activity by heating at a temperature beyond 363K and was inactivated completely at 371K, its nucleation capability was restored by reactivation treatment.
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  • Norio Hirokawa, Yoshio Harano
    1991 Volume 17 Issue 1 Pages 54-59
    Published: January 10, 1991
    Released: November 12, 2009
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    A novel method of characterizing a plastic solid-liquid dispersed system by simultaneous measurement of solid content εp and size of solid dp in the system is presented, taking some solid-fat products as examples.
    This method consists of measuring the permeation rate of the liquid component in the dispersed system through a membrane under constant hydrostatic pressure and of estimating εp and dp by Tempel's and Kozeny-Carman's relations. By its use along with application of the dilatometric method and SEM observation to a standard sample, this method has been found suitable for characterizing plastic solid-liquid dispersed systems such as solid fat products.
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  • Chisato Marumo, Niro Shiomi, Eiji Hayata, Fujio Watanabe, Masanobu Has ...
    1991 Volume 17 Issue 1 Pages 60-66
    Published: January 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The object of this study is to examine the feasibility of producing granular molecular sieving carbon (MSC) from polyvinyl alcohol (PVA) /phenolic resin and the possibility of its practical use for air separation by a pressure swing adsorption (PSA) method. In the present work, laboratory-scale air separation experiments with a PSA apparatus were carried out. As the basic property of MSC, the diffusivity ratio of oxygen and nitrogen was estimated from experimental data of adsorption equilibrium and adsorption rate in a single-component system. From these experiments, the following results were obtained. 1) The fraction of nitrogen in product gas obtained in PSA air separation using granular MSC was more than 99.99%, and the possibility of industrial use of this MSC is strongly suggested. 2) In PSA air separation, the purification of nitrogen was promoted by choosing the most suitable length for pressure equalization and adsorption, and by enlarging the PSA apparatus. 3) Since no significant difference in amount of oxygen and nitrogen adsorbed at equilibrium was found, the separation properties of the granular MSC in this work is suggested to be due to the difference in diffusion rate between oxygen and nitrogen.
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  • Ryoichi Kuboi, Hisakazu Tanaka, Isao Komasawa
    1991 Volume 17 Issue 1 Pages 67-74
    Published: January 10, 1991
    Released: November 12, 2009
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    The effect of various salts added to an aqueous two-phase system on the hydrophobicities of the system and proteins to be separated has been studied as a basis for the effective separation of proteins by this system. In the PEG/Dex (dextran) system, addition of salt causes an increase in the hydrophobic factor (HF) of the system, differing in extent from that in the PEG/salt system. The factor is correlated with a simple relation with concentration difference of PEG in the two phases, as in the case of the PEG/salt system. The salt causes an increase in the surface hydrophobicities of solutes such as amino acid, peptide and protein. Although the absolute value of the hydrophobicity of amino acids is dependent on the salt concentration, the relative value based on glycine is found to be constant in the presence or absence of salt, indicating the validity of the estimation method for HF using the relative hydrophobicity of amino acid defined by Tanford. The increment of the surface hydrophobicity of protein caused by salt addition becomes greater with molecular weight of protein. This is reasonably interpreted by the entropy change of water by salt addition to each system.
    The present results indicate that salt addition is very effective for the separation of proteins of differing surface hydrophobicities and molecular weights.
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  • Ryoichi Kuboi, Hisakazu Tanaka, Isao Komasawa
    1991 Volume 17 Issue 1 Pages 75-80
    Published: January 10, 1991
    Released: November 12, 2009
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    The separation of several proteins of different molecular weight (M=12, 40064, 500), isoelectric point (pI =7.011) and surface hydrophobicity (HFS=-20843.7kJ/mol) has been studied in aqueous two-phase systems consisting of PEG/dextran and PEG/ salt. For proteins of different surface hydrophobicity, HFS, the hydrophobic effect can be used for separation by controlling the hydrophobicity of the system, HF. For proteins of different molecular weight, M, the salt effect can be used for separation since the extent of variation of HFS by the addition of a large amount of salt depends on the molecular weight of the proteins. The electrical potential difference can be controlled by employing a salt with different affinity for one of two phases or varing the partition of a salt between two phases. For proteins with different isoelectric point, pI, the electrostatic effect can be used for separation. Proteins with different surface hydrophobicity, isoelectric point and molecular weight can, therefore, be separated effectively by single or combined effects.
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  • Tadashi Kimura, Toshinori Kojima
    1991 Volume 17 Issue 1 Pages 81-87
    Published: January 10, 1991
    Released: November 12, 2009
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    A numerical model for the local behavior of gas and particle in fluidized bed grid zone was developed and the model was applied to the production of polycrystalline silicon from monosilane diluted with argon via CVD. The validity of the description considering gas and particle behavior in the present model was confirmed by comparison of numerical results with experimental cold-model data of particles velocity and temperature relaxation. A simulation of the level of local monosilane conversion, the rate of production of fine powder and the possibility of clogging in a grid zone considering the local rate of thermal decomposition of monosilane was carried out. The numerical results were compared with previously reported experimental data. The results showed that the contribution of fines formation in the grid zone to total fines formation was negligibly small. And it was considered that fines formed mainly in the upper part of the fluidized bed, i.e. the bubbling zone. The relative ratios of reaction rates, reaction rates to mass flow rate of silicon particle, were defined and calculated as indicators to predict the possibility of clogging. The numerical results of possibility of clogging coincided well qualitatively with our experimental results for the effects of gas velocity, bed temperature, inlet silane concentration and type of gas injector.
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  • Takao Igarashi, Kazuhisa Ohtaguchi, Kozo Koide
    1991 Volume 17 Issue 1 Pages 88-94
    Published: January 10, 1991
    Released: November 12, 2009
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    Saccharomyces cerevisiae containing YEp vector were grown vegetatively. YEp behaves like nuclear DNA and replicates only once during S stage. Our research was aimed at elucidating functions causing the alterations in gene product content under constant dosage by monitoring activity of β-lactamase (bla) from Escherichia coli encoded on the vector. A mathematical description was made to interpret changes in the activity on the basis of the cell cycle, which suggested that the activity per cell could increase or decrease with growth independenly of copy number. We have found that the culture age of inoculum is effective in the upward or downward trend of the activity per cell in logarithmic growth. When cultures from the logarithmic growth phase were inoculated. bla activity per cell decreased with growth. Inocula from the stationary phase, where turnover of bla had progressed, caused an increase. Such trends are seemingly determined at the time of inoculation, Considering that the yields of gene product per cell are variable even under the control of the vector of constant copy number, it is difficult to estimate copy numbers from the yields of gene product.
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  • Hiroshi Ooi, Yoshiharu Tsugou, Mototake Yano, Yoshio Harano
    1991 Volume 17 Issue 1 Pages 95-102
    Published: January 10, 1991
    Released: November 12, 2009
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    NiO/SiO2 fine powdery products prepared by chemical fumed deposition (CFD) were characterized by means of TEM. XRD and TPR. The mechanism of exhibiting the catalytic activity by hydrogen reduction was studied.
    It was observed by TEM that NiO primary particles were agglomerated to form secondary particles of several hundred nm, and that the secondary particles of NiO were dispersed in amorphous SiO2 matrices.
    The presence of readily reducible NiO species was clearly observed by TPR. Coarse NiO particles decomposed into fine nickel particles during hydrogen pretreatment, and sintering phenomena were also observed at high temperatures.
    From the experimental results at several reduction temperatures it was found that the optimum pretreatment temperature was 723K for carbon monoxide methanation.
    Furthermore, if the nickel component is prepared from gaseous phase, one might expect to improve the dispersion of NiO and the reproducibility of the catalyst properties.
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  • Kazuhiko Kudo, Hiroshi Taniguchi, Kehui Guo, Takao Katayama, Takahiro ...
    1991 Volume 17 Issue 1 Pages 103-110
    Published: January 10, 1991
    Released: November 12, 2009
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    Three-dimensional combined radiative and convective heat transfer processes in a furnace for LPG reforming are simulated by introducing the radiosity concept into the radiative heat ray method for accurate radiative heat transfer analysis. Together with an analysis of the chemical reaction in the reactor tubes of the furnace, the heat transfer simulation gives the three-dimensional profile of the combustion gas temperature in the furnace, the tube-surface heat-flux distribution and the composition of the product gas obtained from the reforming.
    The results obtained are as follows.
    1) Increasing the jet angle of the heating burner raises the gas temperature and the tube surface heat flux near the burner entrance
    2) The flame shape is the most important factor for deciding the heat flux distribution of the tube surface because the heat transferred by flame radiation is much more than that by convection of the combustion gas.
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  • Jiro Koga, Hiroshi Yamada, Eiji Suzuki, Kazuo Takeuchi, Shiro Matsumot ...
    1991 Volume 17 Issue 1 Pages 111-118
    Published: January 10, 1991
    Released: November 12, 2009
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    A finite difference scheme was proposed to determine the compressible fluid flow in the impactor. This scheme, based on the Lax & Wendroff and MacCormack ones, does not contain an explicit artificial dissipative term. The simulation results showed that the flow pattern and the separation efficiency of particles were determined by the ratio of downstream to upstream pressure. The effect of the jet-toplate distance and pressure ratio on the separation efficiency curves was studied. The Stokes number for the low-pressure impactor can be defined in terms of gas viscosity and mean free path at the nozzle as for the ordinary pressure impactor. The comparison between separation efficiency curves determined by simulation and measurements showed fairly good agreement at 50 % cut Stokes number.
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  • Masao Sudoh, Takayuki Mukouyama, Masayuki Katsumata, Hiroshi Aoyanagi, ...
    1991 Volume 17 Issue 1 Pages 119-126
    Published: January 10, 1991
    Released: November 12, 2009
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    Bovine serum albumin crosslinked membrane, polyvinylalcohol crosslinked membrane, collagen, chitosan and cellulose acetate membrane were prepared and evaluated by transport properties of oxygen, hydrogen peroxide and glucose through the membranes. A rotating-disk electrode was covered with a membrane, and transient currents by chronoamperometry and steady-state currents were measured to obtain diffusion coefficients and distribution coefficients of oxygen and hydrogen peroxide within the membrane. A diffusion cell was used to obtain permeability of glucose through the membrane. Permeabilities of three substances decreased with decreasing water contents of membranes. Distribution coefficients were close to water contents of the membranes, but the distribution coefficient of oxygen was found to be largest. The permselectivity of oxygen to glucose was found to become larger with decreasing water content of the membrane. Polyvinyl alcohol crosslinked membranes had superior properties of oxygen permselectivity among the other membranes used in this work.
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  • Shigeru Hagimori, Chiaki Kuroda, Masaru Ishida
    1991 Volume 17 Issue 1 Pages 127-134
    Published: January 10, 1991
    Released: November 12, 2009
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    A simulator for continuous bulk polymerization of polystyrene in a stirred reactor, which took account of the inhomogeneity of temperature and concentration in the flow direction, was constructed. By its use the choice of operational variables and rule-based inference in the fuzzy control for changing the conversion were investigated.
    It was found that the univariable fuzzy controller involving manipulation of the coolant temperature operates well when an appropriate mixing speed is chosen. And the cause of unsuccessful control is clearly analyzed from the viewpoint of thermal balance. Controllability is much improved by applying a multivaliable fuzzy controller by manipulating both the coolant temperature with a long time constant and the feed rate of the cool reactant with a short time constant. In continuous operation, the feed rate which has once been used as an operational variable should be restored to a constant set value. This kind of problem is also successfully solved by fuzzy control.
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  • Yukitaka Kato, Takuya Honda, Atsushi Kanzawa
    1991 Volume 17 Issue 1 Pages 135-142
    Published: January 10, 1991
    Released: November 12, 2009
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    A new chemical heat pump using the reaction system of isobutene/water/tertbutanol was proposed for converting low-temperature thermal energy below 373 Kinto high-temperature thermal energy. The possibility of such a heat pump was investigated by equilibrium and kinetic evaluations. The equilibrium evaluation showed the possibility of raising low-level thermal energy above 313K and of raising the temperature more than 40K. The coefficients of performance of the heat pump were calculated from the equilibrium compositions. The activity coefficients of the equilibrium compositions were calculated by the UNIFAC method. The effectiveness of the UNIFAC method was confirmed in practice by the estimation of the solubility of isobutene in tert-butanol solution. The exothermic reaction of isobutene hydration was chosen for kinetic evaluation. The reaction rates were measured and the reaction rate equation was derived from the measured rates. The output capacity was calculated from the exothermic reaction rate and the equilibrium concentration. The kinetic evaluation showed that the output and storage capacities of the reactor were comparable to those of a conventional absorption heat pump.
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  • Naotake Katoh, Syuzou Nakazawa, Kazuhiro Mesaki
    1991 Volume 17 Issue 1 Pages 143-148
    Published: January 10, 1991
    Released: November 12, 2009
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    Sustained oscillations in solute concentration were experimentally verified by a continuous NaCl crystallizer.
    To prevent such instabilities, a double crystallizer system motivated by an idea proposed in the field of emulsion polymerization was examined both by simulation and by experiment.
    Appropriate selections of volume ratio of first to second crystallizer and feed flowrate ratio of first to second crystallizer enabled us to operate the crystallizer system without sustained oscillations.
    It is notable that stable crystallizer operation is realized at the design stage.
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  • Hirokazu Nishitani, Eiichi Kunugita, Yuan-Chen Wan, Masahiro Kujime
    1991 Volume 17 Issue 1 Pages 149-156
    Published: January 10, 1991
    Released: November 12, 2009
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    The dynamic behavior of a chemical plant, including various kinds of process variables, is characterized by linearized ordinary differential equations of which the eigenvalues vary widely in magnitude. In this study a procedure is developed for effective integration of such large and stiff systems. The procedure is composed of the steadystate approximation of some variables and partition into subsystems for reduction of the size of equations to be solved simultaneously. Information about eigenvalues and qualitative knowledge of the system are effectively used to apply these two reduction methods. Execution of these methods can be justified by the resultant eigenvalues. As an illustration, the behavior of a fuel cell power plant with 31 ODEs was simulated effectively by the proposed method.
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  • Hiroshi Takiyama, Yuji Naka, Eiji O'Shima, Takeshi Yamamoto
    1991 Volume 17 Issue 1 Pages 157-165
    Published: January 10, 1991
    Released: November 12, 2009
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    Studies of the static characteristics of a distillation system with a heat pump are carried out, based on simulation and experiments with a pilot plant. A heat pump system is installed between a condenser and an intermediate plate in the stripping section of the distillation system (C/SH distillation system). The main results are as follows.
    a) The relationships among the manipulative variables and the top and bottom products are very similar to those of a conventional distillation system.
    b) If the feed conditions of composition and flow rate change widely, the product specifications can be satisfied by operating conventional manipulative variables.
    c) Exchanging heat loads in the side cooler and heater depend on the compositions of the top and bottom products and on the degree of superheated temperature of a working fluid.
    d) If the optimum feed plate condition is neglected. the temperature difference between a condenser and an intermediate plate can be reduced. This makes the extent of energy recovery higher.
    e) This system reduces steam demand by 34 to 50% in comparison with a conventional column under the present experimental conditions.
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  • Hidefumi Toyohara, Yuji Kawamura
    1991 Volume 17 Issue 1 Pages 166-171
    Published: January 10, 1991
    Released: November 12, 2009
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    Circulation of fludized particles in side regions was studied in two-dimensional tapered beds with apex angles of 30° and 45° and an inlet cross section of 40mm × 40 mm. Colored particles were used as tracer and solid movement in the tapered bed was observed. The circulation rate of solid particles was measured from the descent of tracer particles.
    Steady circulation of fluidized particles was observed between the core and side regions. Incipient circulation velocity uB was measured and estimated. Circulation rate of particles v0 increased with excess gas velocity (ui-uB). The estimations of this rate agreed well with experimental results.
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  • Hidefumi Toyohara, Yuji Kawamura
    1991 Volume 17 Issue 1 Pages 172-178
    Published: January 10, 1991
    Released: November 12, 2009
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    In the case of a binary particle mixture fluidized in a tapered column, a partially fluidizing region was observed at velocities between incipient fluidizing velocity ubf and perfect mixing velocity upf, as observed in conventional fluidized beds with a uniform cross-sectional area. Jetsam particles segregated to the bed tottom. The bed formed core-type segregation that was greatly different from that of conventional beds. In this work, characteristics of such core-type segregation were studied. For this purpose ubf and upf were measured and estimated as well as segregation patterns at various conditions.
    It was found that the segregation tendency in a tapered bed was stronger than that in a conventional bed. This tendecy was evaluated by segregation index S.
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  • Jia-bing Wang, Reijiro Takahashi, Jun-ichiro Yagi
    1991 Volume 17 Issue 1 Pages 179-186
    Published: January 10, 1991
    Released: November 12, 2009
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    For developing a mathematical model of a sludge-melting furnace, a series of experiments were made to obtain the equation of motion for the solid. From the experimental data it was found that the kinematic model is favorable, supporting the applicability of the present mathematical model for estimating the solid flow in a moving bed.
    A staggered differencing technique on boundary-fitted curvilinear grids was used to compute flow and heat transfer in a sludge-melting furnace having an arbitrarily shaped domain. Ergun's equation with an inertial term was used for the equation of motion of gas and a kinematic model was used for the equation of solid flow. Fundamental equations of heat transfer in gas and solid were composed of terms for convection, conduction, heat exchange and heat source. Two-dimensional distributions for the velocities and temperatures of gas and solid were obtained numerically by applying the finite difference method. It was found that the temperature distribution was affected principally by gas and solid flow and that a significant temperature change and high solid velocity appeared within the gas inlet zone. Gas temperature is higher than solid temperatures except in the inlet zone.
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  • Noriyuki Miyazaki, Yuuichiro Aihara, Seiya Hagihara, Tsuyoshi Munakata
    1991 Volume 17 Issue 1 Pages 187-193
    Published: January 10, 1991
    Released: November 12, 2009
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    A computer program was devised for estimating the creep damage of a tube by use of damage mechanics, which has more definite physical meaning than does the linear cumulative damage rule. The program consists of three parts : heat conduction analysis, stress analysis and damage analysis. The finite element method was used for the first two analyses. Thermal strain, creep strain and temperature dependence of material properties are taken into account in the stress analysis. In the present analysis, we utilized the material properties of HK 40 alloy, a typical heat-resistant alloy. We made reference to a reformer furnace tube with respect to a typical size and thermal history of the tube.
    We studied the effects of the creep characteristics of material and operation modes on the life of the tube. The following conclusions were obtained from the present analysis. (1) The life of the reformer furnace tube is greatly affected by thermal stress. (2) The relaxation characteristics of thermal stress as well as creep rupture strength should be considered in selecting tube material. (3) The iterations of startup and shutdown of plants has a great effect on reducing the life of the tube.
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  • Osamu Miyatake, Kazuaki Fujita, Kozo Kibashi
    1991 Volume 17 Issue 1 Pages 194-200
    Published: January 10, 1991
    Released: November 12, 2009
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    An experimental study was carried out to investigate the effect of the installation of a horizontal circular baffle plate near the inlet on the thermal storage performance of a cylindrical water tank, by measuring transient water temperature responses for the case in which hot water wascharged through a vertical inlet tube into the upper part of a tank filled with cold water. Experimental parameters included the diameter of inlet tube, the diameter of baffle plate, the position of baffle plate, the hot-cold water temperature difference, the flow rate, and the water level.
    From the experimental results and theoretical considerations, dimensionless semiempirical equations suitable for predicting the amount of cold water mixed into the hot water region and the thermal storage efficiency of the cylindrical water tank were deduced as a function of the Archimedes number based on inflow conditions, the Peclet number, and three dimensionless geometric parameters.
    The general conclusion reached was that, for relatively low Archimedes numbers. the installation of a baffle plate improved the thermal storage efficiency appreciably due to the prevention of mixing of hot and cold water.
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  • Kazunari Ohgaki, Makoto Morishita, Seiichi Yamamoto, Takashi Katayama
    1991 Volume 17 Issue 1 Pages 201-203
    Published: January 10, 1991
    Released: November 12, 2009
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    High-pressure phase boundaries of binary mixtures consisting of pyrazole and CO2 or C2H6 were investigated around the critical point of the light component in the temperature range from 290 K to 340 K and pressures up to 30 MPa by means of a first-freezing point method.
    Pressure-temperature-composition relations were determined for the observed phase boundaries such as critical lines, three-phase coexistence lines, and critical end-points. These binary systems possessing two critical end-points show similar phase diagrams.
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  • Yuji Takenaga, Masahiro Nawata, Nobuyuki Sakata, Masaru Senuma, Taizo ...
    1991 Volume 17 Issue 1 Pages 204-206
    Published: January 10, 1991
    Released: November 12, 2009
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    The removal of pyrogen using immobilized histidine by a batchwise method was investigated. The pyrogen adsorption depended on ionic strength and was influenced by the shaking speed. The concentration of pyrogen in liquid phase decreased to less than 0.1 ng/cm3 from 20 ng/cm3 by batchwise adsorption with the immobilized histidine when the ionic strength was lower than 0.10 mol/dm3. This indicates that pyrogen could be removed practically by batchwise adsorption.
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  • Eiji Iritani, Takeshi Watanabe, Toshiro Murase
    1991 Volume 17 Issue 1 Pages 206-209
    Published: January 10, 1991
    Released: November 12, 2009
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    To attain high flow-rate separation of macromolecules or colloidal particles from a solvent, ultrafiltration experiments in which the filtrate flow is upward or the membrane is inclined were conducted under constant-pressure conditions, using a deadend filter. A much higher filtration velocity can be achieved by this newly developed technique than that produced by conventional downward dead-end ultrafiltration, because the gel cake growth can be significantly limited as well as the crossflow ultrafiltration. The filtration velocity in the inclined ultrafiltration tends to converge to a constant value which increases with increasing angle of inclination of the membrane.
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  • Kenji Takahashi, Sigeru Mori, Akira Tanimoto, Hiroshi Imai, Kazuo Endo ...
    1991 Volume 17 Issue 1 Pages 210-213
    Published: January 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Methods of evaluating the velocity of a particle falling in an oscillating fluid were proposed. The particle velocity was calculated by a numerical method and by an approximated analytical method in which the fluid drag was estimated by the 2/3-power law of energy dissipation. The calculated particle velocities were compared with the experimental values of Baird et al.. and it was found that the particle velocities were estilnated within ± 20% error.
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  • Norio Arai, Akio Yamamoto, Hitoshi Katsuyama, Masanobu Hasatani
    1991 Volume 17 Issue 1 Pages 213-216
    Published: January 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    An ultrasonic CT method was proposed previously as a new type of indirect thermometry which can measure the temperature distribution of an object without disturbing its internal condition, and its applicability was tested for an axi-symmetrical liquid jet flow. In the present study, to investigate the influence of the shape of the temperature distribution, the method in the previous work was applied to the temperature distribution of a non-symmetrical liquid jet flow and the results were compared with those measured by a thermocouple.
    A minor difference was found in the absolute values, but the temperature distributions measured by the ultrasonic CT method and by the thermocouple resembled each other closely. Consequently, the ultrasonic CT method is considered applicable to the indirect thermometry of a non-symmetrical liquid jet flow.
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  • Shun-ichi Kudoh, Jiro Koga, Shiro Matsumoto, Ichiro Inoue
    1991 Volume 17 Issue 1 Pages 216-220
    Published: January 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The size reduction of milk powder that occurs in a cyclone by the spray drying process increases its free-fat content and degrades its reconstitution properties and keeping quality. A new recovery system consisting of a virtual impactor and cyclones was developed to prevent the size reduction of milk powder.
    The impactor was effective in preventing size reduction and reduced the increase of free-fat content of milk powder.
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  • Hideo Shidara, Mikio Kanzaki, Kenji Mizuguchi, Shigeo Okonogi, Masafum ...
    1991 Volume 17 Issue 1 Pages 220-224
    Published: January 10, 1991
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The sterilizing effect of an ultrahigh-temperature short-time system applied to liquid food flowing in plate heat exchangers was experimentally investigated by the addition of heat-resistant spores. As a result, the addition of the sterilizing effect of the temperature-holding section to that of heating and cooling sections, obtained from calculating the temperature rising and falling curves of the fluid, was effective in estimating the actual death rate of spores.
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