KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 10 , Issue 2
Showing 1-24 articles out of 24 articles from the selected issue
  • Atsushi Inaba, Toshio Yamakawa
    1984 Volume 10 Issue 2 Pages 133-138
    Published: March 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    For the purpose of prospecting the operability of noncatalytic coal liquefaction with solvent, experimental results for Taiheiyo-coal, Wandoan-coal and Yallourn-coal briquet were compared with results computed from a model for the mixed-flow reactor. This model comprised the gas-liquid equilibrium of solvent and disintegration of swelling coal during liquefaction.
    The results of calculation showed that the amount of solvent in the liquid phase of the slurry was small under the conditions in which plugging trouble broke out in the reactor. From this model it was suggested that evaporation of the solvent in the slurry was one of the causes of the coking trouble in the reactor and that the difference of operability with nature of coal was attributable to the difference in the conversion of swelling coal.
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  • Takeshi Kano, Fumiaki Takeuchi, Shuichi Iida, Nobutoshi Mima
    1984 Volume 10 Issue 2 Pages 139-144
    Published: March 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Prior to the experimental study, the stream lines of the flow around the opening of nozzles were analyzed theoretically by conformal mapping so as to predict the most effective type of suction nozzles.
    Four types of nozzles of different shapes were experimentally tested using polystyrene pellets as sample granular material. The mass flow ratio and the power consumption required per unit mass of transported material were compared, and optimal nozzle proportions determined.
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  • Yutaka Hagihara
    1984 Volume 10 Issue 2 Pages 145-149
    Published: March 10, 1984
    Released: November 12, 2009
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    Experiments on molecular distillation of a multicomponent system-polyethylene glycol (average molecular weight=0.3 kg/mol) -were performed by use of a pot still under a residual air pressure less than 0.13 Pa. The following results were obtained : (1) In the domain of evaporation without molecular-burst (M-B) evaporation, polymerization grade (mob) of distillate observed at each fraction is equal to the value (mcal) calculated under the condition of ideal solution and constant liquid surface temperature (140°C). This result indicates that a multicomponent solution can be regarded as an ideal solution in this domain. (2) In the domain of evaporation with M-B evaporation, mob does not agree with mcal. The cause of this disagreement is that relative volatility becomes smaller than the theoretical value by M-B evaporation. In this domain, a multicomponent solution cannot be regarded as an ideal solution. (3) An equation which represents the relationship between liquid weight and its composition in the pot still can be derived from the evaporation rate equation (Langmuir's equation). In the domain of evaporation without M-B evaporation, the relationship obtained experimentally is accurately estimated by using this equation and theoretical relative volatility.
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  • Masayoshi Sadakata, Yasushi Kurosawa, Tadao Arai, Junichi Saito, Atsus ...
    1984 Volume 10 Issue 2 Pages 150-157
    Published: March 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The effect of primary air velocity on the emission of NOx from pulverised coal combustion was investigated by using a model furnace which was designed to realize practical combustion conditions. The primary air velocity is an important aerodynamic parameter in the combustion of volatile matter. Measurements of velocity profile in the furnace were carried out by using a symmetrical type probe. This probe was newly developed for the measurement of velocity under the combustion conditions of pulverized coal. The following results were obtained.
    The emission of NOx was decreased to less than half of that at maximum velocity as the primary air velocity was decreased from 68 m/s to 11 m/s. The measurement of NOx distribution in the furnace revealed that this decrease of NOx at the furnace exit was associated with the decrease in emission of volatile NOx in the volatile combustion region. From the measurement of stable species concentration distribution, it was indicated that the emission of volatile NOx was suppressed by the appearance of a local reduced region which was formed in the volatile combustion region under the condition of low primary air velocity. The formation mechanism of this local reduced region, which significantly contributed to the reduction of NOx was revealed from the measured result of the axial change of the primary air jet flow quantity and the observed result of the ignition point.
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  • Akira Sannomiya, Koichi Ichimura, Mototake Yano, Yoshio Harano
    1984 Volume 10 Issue 2 Pages 158-165
    Published: March 10, 1984
    Released: November 12, 2009
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    Reduction of supported nickel oxide was studied as a standard sample for comparison with reduction kinetics of supported nickel oxides. The induction period of the reduction is governed by the constant growth rate of nuclei. The activation energy of this step is 196.6 KJ/mol and the following reduction step is described by a surface reaction of unreacted core model with an apparent activation energy of 55.6 KJ/mol.
    The reduction rates of supported nickel oxides using α-Al2O3 (TAS-99235), γ-Al2O3 (ALO-4) and SiO2 (Aerosil-200), as supports are represented by first-order kinetics with respect to nickel oxide and hydrogen pressure, and their activation energies E are linearly increased with the extent of reduction a, i.e. E=E0+gα, where E0 is the initial activation energy of reduction, and g is a proportional factor.
    The catalysts were prepared by varying supports, calcination conditions and preparation method, and from measurements of the reduction rate of the catalysts, it was found that the interactions between support and nickel oxide were strengthened in following order under the same impregnation method,
    SiO2<α-Al2O3<γ-Al2O3
    and for the same support, impregnation<deposition<coprecipitation
    These orders so coinside with the published order of the interaction, that the values of g can be used as a measure of the interactions.
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  • Etsuro Naito
    1984 Volume 10 Issue 2 Pages 166-172
    Published: March 10, 1984
    Released: November 12, 2009
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    An analytical solution is tried for the laminar hear transfer problem of simultaneous development of hydrodynamic and thermal boundary layers in the entrance region between parallel plates with uniform wall temperature. This investigation is developed further from Sparrow's integral method employing the Karman-Pohlhausen method. To improve Sparrow's result for higher accuracy, the velocity and temperature profiles in the hydrodynamic and thermal boundary layers are approximated by fourth order polynomials. The boundary-layer shape factor σ is given by the power series of the dimensionless hydrodynamic boundary-layer thickness ε, so that the energy equation is solved by the method of undetermined coefficients. The analytical solutions corrected by the numerical solution are in good agreement with the numerical solutions within 0.6 % average error, and are of much practical use comparing the numerical results of other authors. The local and average Nusselt numbers are compared with the other results.
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  • Ikuro Shishido, Masaru Ogino, Mutsumi Suzuki, Shigemori Ohtani
    1984 Volume 10 Issue 2 Pages 173-180
    Published: March 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A prediction method is presented for critical moisture content in a continuous dryer where the drying rate is described as a function of time.
    Error analysis indicates that a semi-infinite model is suitable for the case of rapid drying within a few percent relative error. A steady-flux-ratio model is applicable as an alternative for mild drying with a maximum of five percent error.
    A continuous drying simulator was constructed by use of a micro-computer system. The critical moisture content, obtained for various drying conditions, was compared with these models.
    The usefulness of the prediction method is confirmed through comparison between experimental and predicted critical moisture content.
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  • Tae-Hwan Cho, Kenji Ochi, Kazuo Kojima
    1984 Volume 10 Issue 2 Pages 181-183
    Published: March 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Recently, we proposed a method for measuring isobaric vapor-liquid equilibrium for binary systems with limited miscibility. The method involves the determination of the dew-point isobar by means of a vapor mixing method and the bubble-point isobar by means of an ebulliometric method. In the present work, this method was applied to measure the vapor-liquid equilibrium data for the binary systems water-n-amyl alcohol and water-isoamyl alcohol at 101.325 kPa. The experimental vapor-liquid equilibrium data were checked for thermodynamic consistency by means of the rigorous equation proposed in the earlier paper. The enthalpies of mixing data necessary for the consistency test, which were measured at 298.15 K, and the vapor pressure data of isoamyl alcohol were reported together.
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  • Hiroyuki Hatano, Masaru Ishida
    1984 Volume 10 Issue 2 Pages 184-191
    Published: March 10, 1984
    Released: November 22, 2010
    JOURNALS FREE ACCESS
    Local gas concentration around a single bubble rising in a two- or three-dimensional fluidized bed was measured in detail by penetrative optical fiber probes. The relation between cloud radius determined by a video system (VTR) and gas concentration profiles detected by optical fiber probes was demonstrated in the two-dimensional bed.
    Based on this, the observed cloud radius and gas concentration profiles in the cloud phase in the three-dimensional bed were compared with those predicted by previous models. In particular, the effect of the ratio of bubble rising velocity to interstitial gas velocity was examined for various kinds of particles as well as of fluidizing gas, and the following empirical formula for the interphase mass transfer coefficient was proposed.
    kob=0.127D1/3g1/3α-2/9
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  • Masashi Momonaga, Fumio Hibi, Hisatoyo Yazawa
    1984 Volume 10 Issue 2 Pages 192-197
    Published: March 10, 1984
    Released: November 12, 2009
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    The crystallization of phenoxy acetic acid compounds was investigated for batchwise operation.
    From experimental results, representative particle size Dp and Max F (Dp) representing the maximum of particle size distribution are correlated as the following correlative equations including agitation effect.
    Dp=4.64×10-2-8.75×10-5 Ndθc
    Max F (Dp) =-420 Z+1.02×103
    θc is mean circulation time and Z a dimensionless number including rotational speed of impeller N, impeller diameter d, vessel diameter D and particle diameter Dp.
    The correlative equations to control particle size distribution could be applied to an 80-fold scale-up of the geometrically non-similar crystallizer.
    Therefore, it is considered that the dimensionless parameter Z is applicable as a scale-up factor for the geometrically non-similar crystallizer.
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  • Hikoji Inazumi, Takanori Suzuki, Shuhei Yada, Yuji Honma
    1984 Volume 10 Issue 2 Pages 198-203
    Published: March 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The usability of the laminar boundary layer theory, in which the surface velocity of falling liquid film is taken into account, for the estimation of gas-phase mass transfer rates in cocurrent gas-liquid contact operations on a vertical flat wall was examined experimentally.
    Experiments were carried out for the vaporization of four different organic liquids (MeOH, EtOH, IPA and CCl4) into air flowing over a wetted surface in a square duct. Velocity and concentration profiles in gas stream near moving liquid surface were measured, along with surface temperature profiles of the liquid film.
    The experimental values of velocity and concentration profiles in the gas phase agreed well with those obtained from the numerical solutions in this work.
    It was confirmed that the experimental values of modified Sherwood numbers for the gas phase agreed well with those obtained from the numerical solutions in this work and also with the approximate solution by Shirotsuka et al.
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  • Yoshikazu Kuga, Jiro Koga, Kenji Yamaguchi
    1984 Volume 10 Issue 2 Pages 204-210
    Published: March 10, 1984
    Released: November 12, 2009
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    Soma sand and Neobead particles were pulverized by a screen mill. The particle size of feed was varied in the range from about 44 to about 1000 μm. The material balance was expressed in matrix form from the size distributions of products. The simulated results of two and three stages of grinding were in good agreement with the experimental ones. These results show that breakage is subject to a first-order law. Then the selection function and the breakage function were determined by the material balance equation under the assumption that the mill is operating in fully mixed condition.
    Consequently, both functions are approximately described as the power function of the particle size. The characteristics of the size distributions of products are well explained by them. The value of power is in the range from about 2 to about 4. It has a tendency to be large with increasing impact velocity.
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  • Ikuho Yamada, Pin Quan Chan, Masatoshi Sawada, Setsuro Hiraoka, Hideki ...
    1984 Volume 10 Issue 2 Pages 211-218
    Published: March 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A matrix method is proposed to obtain a further rigorous solution in practical use of multicomponent distillation problems of the operation type by considering both partial condensation of vapor, which is caused by the heat loss through the column wall, and liquid entrainment from the plates. In this method a direct iteration approach is used for the terms related to the partial condensation and entrainment with the EV-matrix method of Yamada et al. The usefulness of the proposed method is illustrated by a numerical example of quaternary n-paraffin system, and the effect of partial condensation and entrainment on vapor and liquid loads through the column is also illustrated.
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  • Hitoshi Kosuge, Yasuhiro Mochizuki, Koichi Asano
    1984 Volume 10 Issue 2 Pages 219-225
    Published: March 10, 1984
    Released: November 12, 2009
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    Experimental studies on vapor-phase mass and sensible heat fluxes in ternary distillation of the acetone-methanol-ethanol system were made by a vertical flat-plate wetted-wall column under total reflux conditions.
    Observed vapor-phase diffusion fluxes of each component were found to be proportional to their concentration driving-forces, whereas observed vapor-phase mass fluxes were not. Dimensionless vapor-phase diffusion fluxes and sensible heat fluxes showed good agreement with laminar boundary layer theory with mass injection and suction.
    Simulation of the distillation path for ternary distillation by a vertical flat-plate wetted-wall column were made, and it showed good agreement with the observed distillation paths.
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  • Katsuhiko Fujinawa, Tamami Komatsu, Mitsunori Hozawa, Nobuyuki Imaishi ...
    1984 Volume 10 Issue 2 Pages 226-232
    Published: March 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The rate of swelling of the W/O emulsion in (W/O) /W type liquid membrane process was studied experimentally using a stirred cell. The swelling rates by permeation of water through the membrane phase and those by mechanical entrainment were measured separately, using a tracer method and Karl Fisher's method. As oil phase and surfactant, kerosene and Span 80 were used respectively. The following points were found. 1) The capacity coefficient for water permeation based on osmotic pressure increases with concentration of surfactant Cs and decreases with volume fraction of inner water phase φ. 2) Mechanical entrainment occurs at the early stage of agitation, increasing with Cs and decreasing with φ. 3) Raising the viscosity of the membrane is effective in depressing the rate of swelling. 4) As the drop size of the inner water phase decreases, the rate of swelling also decreases.
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  • Junichi Shiozaki, Hisayoshi Matsuyama, Kouichi Tano, Eiji O'shima
    1984 Volume 10 Issue 2 Pages 233-239
    Published: March 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The algorithm for fault diagnosis by use of the signed directed graph was improved, where the thresholds distinguishing normal and abnormal states based on qualitative information about the process are to be applied. The algorithm was implemented on a microcomputer to be tested for fault diagnosis of a pipeline system as an experimental example. It was proved through experiment that the present algorithm possesses potential applicability to practical process systems.
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  • Yoshifumi Tsuge, Junichi Siozaki, Hisayoshi Matsuyama, Eiji O'shima, Y ...
    1984 Volume 10 Issue 2 Pages 240-246
    Published: March 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    An experimental investigation to verify the practical applicability of the method of fault diagnosis based on the signed digraph was performed with the use of a chemical process pilot plant with two chemical reactors where gas-liquid exothermic reactions in the presence of solid catalyst take place. The object was to identify eleven different causes of failure. It was confirmed, as the consequence of the experiments, that the feasibility of applying the algorithm is promising with the condition that the sensors are allocated properly to assure the promptness and accuracy of diagnosis.
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  • Yasuharu Akagi, Teruo Takahashi
    1984 Volume 10 Issue 2 Pages 247-251
    Published: March 10, 1984
    Released: November 12, 2009
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    Ranges and flow rates of liquid weeping accompanied by bubble formation at a submerged single orifice were investigated experimentally.
    The liquid weeping rates were measured under the following conditions : orifice diameter (2-12 mm), plate thickness (1-10 mm) and chamber volume (50-28, 000 cm3).
    The liquid weeping rates increase with increasing orifice diameter (d) and decrease with increasing chamber volume (Vc). The effect of plate thickness on weeping rates is small. The ranges of d and Vc in which weeping occurred were determined and correlations of the ranges of gas flow rates with the weeping were proposed as a function of d, Vc, etc. It became clear that the maximum weeping rates and the gas velocity at the maximum weeping point were also correlated by d, Vc, etc.
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  • Takeshi Yasui, Toshio Tsutsui, Terukatsu Miyauchi
    1984 Volume 10 Issue 2 Pages 252-260
    Published: March 10, 1984
    Released: November 12, 2009
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    FCC particles and two other types of particles, which are “A particles” in Geldart's classification, were fluidized in beds of diameter 5.2 to 50 cm in a wide range of superficial gas velocities up to about 60 cm/s, in order to study the fluidized states of these particles. The latter particles are characterized by nearly the same mean particle size, size distribution and weight fraction of fines under 44 μm as FCC particles, but by larger particle densities.
    Severe channeling occurred when deep beds of these heavy particles were fluidized, although FCC particles were found in a smoothly fluidized state. This channeling could be weakened when the fluidizing gas velocity was raised to a certain value, which was found to be dependent on the density of the particles. Good fluidity of particles in fluidized catalyst beds cannot always be given, due only to wide size distribution and small mean size of the particles, and the density of the particles has an important effect on the fluidity.
    It was found possible to evaluate the fluidity of particles by plotting gas hold-up data based on the recirculation theory for bubble columns.
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  • Kohei Ogawa, Hiroshi Yukawa, Masatoshi Takagi, Masaru Hakoda, Chiaki K ...
    1984 Volume 10 Issue 2 Pages 261-271
    Published: March 10, 1984
    Released: November 12, 2009
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  • 1984 Volume 10 Issue 2 Pages 272a
    Published: 1984
    Released: November 12, 2009
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  • 1984 Volume 10 Issue 2 Pages 272b
    Published: 1984
    Released: November 12, 2009
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  • 1984 Volume 10 Issue 2 Pages 272c
    Published: 1984
    Released: November 22, 2010
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  • 1984 Volume 10 Issue 2 Pages 272d
    Published: 1984
    Released: November 22, 2010
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