KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 12 , Issue 5
Showing 1-20 articles out of 20 articles from the selected issue
  • Toshio Kawaguchi, Toshihisa Wakasugi
    1986 Volume 12 Issue 5 Pages 499-505
    Published: September 10, 1986
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The catalyst deterioration rate in vinyl acetate synthesis from acetylene was studied by use of commercial operation data for the industrial fluidized-bed reactor, using the catalyst of zinc acetate supported on activated carbon.
    It was confirmed that the deterioration rate of catalyst activity was directly proportional to the catalyst activity expressed by space-time yield (S. T. Y.). The deterioration rate constant was studied in relation to reaction conditions. The deterioration rate constant was calculated by the decline rate of the apparent activity in the case of feeding fresh catalyst into the reactor at a constant ratio.
    It was found that the deterioration rate was affected highly by acetic acid conversion α and reaction conditions, especially temperature and mole ratio M.R., and was represented by the following equation.
    -d (STY) /dθ=κpo (STY) {α (M.R.-α) / (1-α) 2} 2
    The deterioration rate constant κpo depended on the reaction temperature alone, and its activation energy was 105kJ·mol-1.
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  • Tetsuro Adachi, Katsuya Ebara, Kenkichi Izumi, Toshikazu Shindo
    1986 Volume 12 Issue 5 Pages 506-512
    Published: September 10, 1986
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The filtration mechanism for a precoat type filter using powdered ion exchange resin as filter aid was investigated with a small experimental filter.
    Where iron oxide particles, α-Fe2O3, are used as suspended solids, the charge of resin flock consisting of anion exchange resin and cation exchange resin is neutralized when particles are captured by the precoat resin layer. So resin flock disperses and pore size of the resin layer becomes small with time.
    It was found that the mechanism of capturing particles is depth filtration and, in addition, cake filtration that begins to occur locally and spreads over all the filter area gradually.
    In addition, an experimental expression of the pressure differential of the filter in depth filtration and cake filtration was obtained and was usable to evaluate the pressure differential rise caused by captured particles.
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  • Osamu Kashihara, Toshihiro Nakata, Yoshio Harano
    1986 Volume 12 Issue 5 Pages 513-518
    Published: September 10, 1986
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The effects of some inorganic substances on the metastable zone width, ΔTm, in quiescent aqueous solution of KBrO3 were measured calorimetrically by a differential scanning calorimeter with the constant cooling rate method, and the following results were obtained.
    Cation as impurity caused acceleration of nucleation in the following order : Fe3+, Cr3+<Pb2+, Ca2+<Na+, in the region of low concentration. And Fe3+, Cr3+ were depressed in this region.
    Anion as impurity caused depression of nucleation and this tendency was SO42->Br->NO3-.
    Through non-isothermal analysis of nucleation rate, these impurity effects were under stood to stem not from the change of intensive factor σ in nucleation rate, but from the variation of frequency factor κ2 with diffusion term.
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  • Masanobu Hasatani, Hitoki Matsuda, Akihiro Kataoka
    1986 Volume 12 Issue 5 Pages 519-524
    Published: September 10, 1986
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    By use of a packed bed of iron oxide pellets, high-temperature direct removal of H2S and SO2 from low-calorie gas produced from low-grade solid fuels was investigated experimentally and theoretically.
    The desulfurization characteristics showed almost no significant change with repetition of the reaction cycle between the sulfurization and the regeneration, but its rate gradually decreased with increasing iron oxide pellet size owing to the presence of intrapellet mass transfer resistance. The experimental data obtained agreed well with results of the theoretical simulation in terms of the breakthrough of H2S within the range of experimental conditions employed. Further, the iron oxide pellets bed was observed to be effective for SO2 removal. SO2 was considered to be converted to H2S at first in a reduction atmosphere and then to be removed by reaction between H2S and iron.
    Consequently, the present proposed high-temperature desulfurization process may be applicable to sulfur removal from gas, including not only H2S but also SO2.
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  • Takeichiro Takamatsu, Iori Hashimoto, Yoshihiro Hashimoto, Yoshitaka T ...
    1986 Volume 12 Issue 5 Pages 525-534
    Published: September 10, 1986
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    To reduce the interaction in dual composition control of a distillation column, the authors previously published a noninteracting control system in which the ratios of vapor and liquid flow rates are selected as a pair of manipulated variables. In this paper, the effectiveness of the proposed control system is theoretically confirmed. The interaction between control loops is examined not only at the steady state but also in the high-frequency domain. It is made clear that the proposed control system can always reduce the interaction in the high-frequency domain, independent of column characteristics such as number of stages, output specification and so on. This control system can also make the interaction in the low-frequency domain less than that of the conventional control system. The following facts are also confirmed. By increasing the number of stages, the boil-up rate can be decreased and it makes the interaction between composition control loops weak. From this fact a distillation column having low interaction can be designed.
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  • Masaru Nakaiwa, Masaru Owa, Takaji Akiya, Shigetake Kawasaki, Veerapot ...
    1986 Volume 12 Issue 5 Pages 535-541
    Published: September 10, 1986
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    In this study, we extend the McCabe-Thiele method to a plate-to-plate heat-integrated distillation column, which can save substantial energy, for analyzing column design and performance. By using this procedure, the total number of stages, number of heat transfer stages and heat transfer area can be calculated when the specifications of feed and products are given and reflux ratios and operating pressures are set for the rectifying section and the stripping section. The total energy consumption, including compression work, can be also obtained by calculation.
    As a calculation example, we apply this procedure to the benzene-toluene binary system in distillation and show how it can be useful in design.
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  • Yoshiki Shigaki, Hideaki Orimo, Masato Fukushima, Yuji Mukai, Naoshi O ...
    1986 Volume 12 Issue 5 Pages 542-549
    Published: September 10, 1986
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    New prediction methods for four basic properties, (normal boiling point, Tb, critical temperature, Tc, critical pressure Pc and Pitzer's acentric factor, ω) are proposed, based on group contribution techniques. Object substances of these methods are mainly halogenated hydrocarbons (flons), which contain undeveloped substances whose chemical formulas are given. The acentric factor can be given through a new correlation with a parameter β in the Frost-Kalkwarf-Thodos vapor pressure equation. New group contribution techniques for Tb and β are developed. As for Tbr, six group increments are newly added to that of Lydersen. Furthermore, Pc can be indirectly calculated from a new empirical correlation among Pc, Tbr and ω. Average deviations (root mean square of deviations) of the proposed methods for Tb, Tc, Pc and ω are found to be about 1 %, 1 %, 3% and 3 %, respectively.
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  • Miyuki Kojima, Junzo Aoi, Hiroshi Tsuchiya, Takeo Nagasawa, Hiroshi Ko ...
    1986 Volume 12 Issue 5 Pages 550-556
    Published: September 10, 1986
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    It is well known that the important parameters for the kraft cooking reaction are reaction time, temperature, alkali concentration and chip thickness.
    In this paper, it is calculated on the basis of 3n typed orthogonal arrays that these five variables significantly affect cooking reaction for two wood species, beech (Fagus crenata) and red pine (Pinus densiflora). The interactions among these variables can be neglected in the range of these experiments. Further, this report concerns the derivation of cooking reaction-rate equations verified by long-duration cooking experiments.
    From other cooking data for various chip thicknesses, reaction rate for each chip thickness is calculated to indicate the effect of reagent diffusion into wood chips.
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  • Ko Higashitani, Akiko Kage, Naoaki Kurita
    1986 Volume 12 Issue 5 Pages 557-562
    Published: September 10, 1986
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The effect of the zeta-potential of coal particles on the viscosity and stability of 40 wt % coal-water slurries is investigated, and the factors controlling the zeta-potential of coal particles are also examined. It is found that the zeta-potential of particles is affected by the inorganic salts dissolved from the coal ash into the medium, the pH of the medium and the additives adsorbed on the particle surface, and that the viscosity and stability of slurries are governed by the zeta-potential when |ζ| <40 mV. Whether cationic polymers of low molecular weight may be used as the additive of CWM slurries is also examined.
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  • Koichi Asano, Izumi Taniguchi, Hironobu Nishimura
    1986 Volume 12 Issue 5 Pages 563-568
    Published: September 10, 1986
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Measurements were made of the effect of an adjacent solid sphere on the respective rates of evaporation of a drop of water, n-octane, n-hexane and n-pentane into dry air at high ambient temperatures in a moderate Reynolds number range.
    The rates of evaporation of a less-volatile drop were found to be affected by the diameters of solid spheres and drops as well as by the distances between the drop and solid sphere. A new correlation for the effect of adjacent solid sphere on the rates of evaporation was proposed.
    The data for n-pentane drops showed high mass flux effect, as was the case for the single drop. All the data showed good agreement with the low flux correlation after due consideration of the effect of high mass flux and of variable properties by use correlation for a single drop were made.
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  • Tadashi Shirotsuka, Kaoru Onoe, Yukihisa Muramatsu
    1986 Volume 12 Issue 5 Pages 569-574
    Published: September 10, 1986
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Most conventional studies of the kinetics of coal liquefaction have been concerned only with the weight decrease of residue. However, it is important to study the coal particle size change to design the residue separation process. Therefore, liquefaction experiments were carried out with 16/20 mesh Taiheiyo coal, and the changes in residue weight, particles size and density were investigated.
    It was demonstrated that the reaction could be divided into three regions on the basis of density change : I. Both apparent and intrinsic densities change considerably, and particles swell rapidly. II Only the apparent density becomes constant and particles shrink slowly. III. Both densities become constant, and particles shrink slowly and steadily.
    Regions II and III were analyzed by new models, in which changes in both residue weight and particle size were considered : the double shrinking core model, which is combined with the shrinking core model and the parallel reaction model, was applied to region II, and the shrinking core model was applied to region III. The validity of these models was confirmed.
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  • Kazumori Funatsu, Toshihisa Kajiwara
    1986 Volume 12 Issue 5 Pages 575-581
    Published: September 10, 1986
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A method was devised for analyzing an approximately axisymmetric stress field. It was assumed in the method that the extinction angle obtained from the isoclinic pattern is almost equal to the inclination of the principal axis of a refractive index ellipsoid and that the phase difference is dependent only on the local values of the double refractive index. An approximate equation was employed to analyze the local values of the primary double refractive index.
    This method was applied to analysis of stress for the flow around a sphere as an example of an axisymmetric flow field. According to the results of numerical calculation of the extinction angle and the optical equation, it was found that the above assumptions were reasonable. Values of the primary refractive index obtained by using the equation were somewhat lower than the actual value.
    It may be concluded that the method is effective for approximate stress analysis of axisymmetric flow fields with double refractive indices rising to the axis, if suitable correction for double refractive indices is made.
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  • Kazumori Funatsu, Toshihisa Kajiwara, Yukihiro Shiraishi
    1986 Volume 12 Issue 5 Pages 582-588
    Published: September 10, 1986
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Distributions of the primary normal stress difference and shear stress in creeping flow around a falling sphere were measured by the transmission light flow birefringence technique. Both distributions measured were found to be reasonable qualitatively and were considerably different in the neighborhood of the sphere from exactly analyzed values for a Newtonian fluid with the same value of viscosity, because of the elastic effect.
    The drag force acting on the sphere was calculated and used for quantitative evaluation of the measured values. The value calculated from the measured stress distributions was found to be close to the directly measured value, if suitable correction is made.
    It may be concluded that the transmission light flow birefringence technique can be employed for analyzing the stress distributions in axisymmetric flow fields with double refractive indices rising to the axis.
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  • Shunya Ikumi, Hisao Wakayama, Hiroaki Masuda
    1986 Volume 12 Issue 5 Pages 589-594
    Published: September 10, 1986
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Particle reentrainment was experimentally investigated by use of a cylindrical duct. Fully dispersed fly ash aerosol particles formed a particle layer on the inside wall of the duct through particle deposition. Then the particles were reentrained as the air velocity was increased step by step. The reentrainment phenomenon was observed by use of a T.V. monitor and recorded on a video tape.
    It has been found that the reentrainment depends greatly on the structure of the particle layer. The smaller the packing fraction of the particle layer or the larger the surface roughness is, the more easily reentrained are the particles as an aggregate. The reentrainment velocity has been well correlated with the packing fraction and the surface roughness. It was also found that the reentrainment of smaller aggregates is less frequent than that of larger aggregates. The diameter of the smallest aggregate reentrained (critical diameter) corresponds to the maximum separation force of the air stream. The critical diameter is found to be inversely proportional to the initial roughness of the particle layer and decreases exponentially with increasing air velocity. These experimental results were explained qualitatively by an analysis in which a force balance is assumed between the air drag for aggregate particles and the tensile strength of the particle layer.
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  • Masashi Kuramae
    1986 Volume 12 Issue 5 Pages 595-602
    Published: September 10, 1986
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The effect of microscopic temperature distribution upon local mass transfer rate in porous media such as a granular bed under a temperature gradient was investigated. Local temperature and mass transfer rate distributions were measured by model experiments, and the results were compared with analytical results calculated by the boundary element method.
    Experimental results for two solid hemispheres of different thermal conductivities were fairly consistent with the calculated ones and it was shown that the local mass transfer rate in porous media under temperature gradient was characterized by a microscopic void temperature distribution induced by the difference in thermal conductivities of the solid and the void filled with air.
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  • Kenji Fukuchi, Yasuhiko Arai
    1986 Volume 12 Issue 5 Pages 603-607
    Published: September 10, 1986
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Adsorption equilibria of 15 single solutes (acetone, ethyl methyl ketone, pyridine, phenol, p-cresol, p-chlorophenol, p-nitrophenol, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol and 1-pentanol) from dilute aqueous solutions on activated carbon were measured at 25°C and for concentrations up to 100-2500 mmol · dm-3. The Radke-Prausnitz equation and the vacancy solution model were applied to correlate the present adsorption equilibrium data. It was found that they can correlate each isotherm within 2-3 % error.
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  • Katsutoshi Inoue, Hironori Shishido, Yasuo Yamazaki, Yukihiro Watanuma ...
    1986 Volume 12 Issue 5 Pages 608-624
    Published: September 10, 1986
    Released: November 12, 2009
    JOURNALS FREE ACCESS
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  • 1986 Volume 12 Issue 5 Pages 625a
    Published: 1986
    Released: November 12, 2009
    JOURNALS FREE ACCESS
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  • 1986 Volume 12 Issue 5 Pages 625b
    Published: 1986
    Released: November 12, 2009
    JOURNALS FREE ACCESS
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  • 1986 Volume 12 Issue 5 Pages 625c
    Published: 1986
    Released: November 12, 2009
    JOURNALS FREE ACCESS
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