KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 10 , Issue 3
Showing 1-18 articles out of 18 articles from the selected issue
  • Saburo Yashima, Taiji Yamamoto, Hiromitsu Horita, Yutaka Arai
    1984 Volume 10 Issue 3 Pages 273-279
    Published: May 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The effects of grinding aids on the dry fine grinding of petroleum pitch were studied by means of laboratory-scale batch ball milling experiments.
    The experimental results are summarized as follows : 1) It was shown that the grinding of petroleum pitch with additives could be described by the grinding rate equation, based on a mass balance, which consists of breakage parameter, selection parameter, grinding efficiency parameter and specific energy of size reduction. 2) The grinding aids for petroleum pitch acted well in dry fine grinding when fine powders were build up in the mill and/or the grinding rate slowed down. 3) The mechanism of the effect of the grinding aids in the fine grinding of petroleum pitch could be represented by the 3-dimensional graphic method. By using this representation, their effects could be precisely evaluated. 4) The action of grinding aids in the fine grinding of petroleum pitch was considered to be a checking of the growth of agglomerates by intervention between fine particles of petroleum pitch.
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  • Hiromoto Usui, Yuji Sano, Kazutoshi Iwashita, Akio Isozaki
    1984 Volume 10 Issue 3 Pages 280-286
    Published: May 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The combined use of an internally grooved rough tube and a twisted tape was proposed as a technique for enhancing heat transfer in single-phase turbulent heat transfer. A remarkable increase in heat transfer efficiency was obtained when the heat transfer promoters satisfied the following conditions. 1) The tape should be counter-twisted against the rotation of the grooves. Better performance was obtained when the cross angle between the twisted tape and the groove was near 90 degrees. 2) Relative roughness of groove should be considerably large. Typically, 2.2% of relative roughness to the tube diameter gave better enhancement of heat transfer than the case of 1.1 % of relative roughness. The best performance of the heat transfer promoter proposed in this work can be stated as follows : The heat transfer coefficient at the same pumping power consumption reached 3.0-3.5 times larger than that of a smooth tube, and a 70-75% reduction of heat transfer surface compared with a smooth tube was obtained under conditions of the same pumping power and the same heat duty.
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  • Tadaatsu Ido, Hajime Tariki, Kouki Sakurai, Shigeo Goto
    1984 Volume 10 Issue 3 Pages 287-293
    Published: May 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Oxidation of benzyl alcohol in toluene (organic phase) by sodium hypochlorite in distilled water (aqueous phase) was investigated at 303 K in a batch reactor containing one of two kinds of anion exchange resins (solid phase) : a gel type, Dowex 1 X8, and a macroporous type, AGMP-1. A consecutive reaction of first order took place in the aqueous phase and on the solid phase.
    For both anion exchange resins, as particle sizes increased the reaction rates and the selectivities decreased. Mass balance equations with resistance of intraparticle diffusion were developed and solved numerically. The effective surface diffusivities could be obtained by fitting the calculated values of concentration changes with time to the observed ones. The effective surface diffusivity for the macroporous type was 1.7 times of that for the gel type.
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  • Yasuo Kato, Makoto Koyama, Tokihiro Kago, Shigeharu Morooka
    1984 Volume 10 Issue 3 Pages 294-299
    Published: May 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The heat transfer coefficient between bed and horizontal tube wall was measured in three-phase fluidized beds of 19 and 12 cm i.d. Glass spheres with different diameters (particle diameter-0.052-0.22 cm, particle density =2.5 g·cm-3) and alumina spheres (particle diameter =0.32 cm, apparent particle density=1.62 g·cm-3) were fluidized by the fluid media of air-water or air-aqueous solution of carboxymethyl cellulose. The superficial velocities of gas and liquid were varied in the range of 2.0-16 cm·s-1 and 0.1-8.0 cm·s-1, respectively.
    The heat transfer coefficient, h, in the fluidized state was correlated as follows.
    Nu'=0.12 {(dh0+dh/dh) 0.5 (Re'·Pr) 0.65+0.12Frh0.5} +1.3Frp0.33
    where Nu'=hdpεl/ {kl (1-εl)}, Re'=dpulρl/ {ηl (1-εl)}, Pr=cplηl/kl, Frh=ug2/ (g·dh), Frp=ug2/ (g·dp), dh0=2cm, dh=tube diameter, kl = thermal conductivity of liquid, ug=superficial gas velocity, ul=superficial liquid velocity, εl =liquid holdup, ηl =liquid viscosity, ρl =liquid density.
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  • Megumu Yusawa, Masanobu Hasatani
    1984 Volume 10 Issue 3 Pages 300-307
    Published: May 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    For the suitable selection of calcium-based sorbents of SO2 in FBC of coal, reactivities of CaO pellets prepared by calcination of various kinds of limestones were compared on the basis of the results from a TGA study within the range of reaction conditions : temperature, 700-1100°C and pellet diameter, 5-1000 μm.
    For ultra-fine pellets (5 μm), the chemical reaction rate controls the overall rate and there is hardly any variation in SO2 reactivity among the CaO pellets employed.
    For CaO pellets larger than 300 μm, the intrapellet pore volume decreases as the calcination temperature rises. Pellets prepared from Coral Reef Rock (CRR) have the largest value of pore volume among the CaO pellets employed.
    With increase in pellet diameter, the effect of intrapellet diffusion rate of SO2 on the overall rate becomes increasingly significant but depends largely upon the initial pore volume of the CaO pellet, i.e. calcination temperature and original limestone. As a result, the CaO pellets prepared from CRR have the largest value of SO2-saturation capacity.
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  • Akira Yasunishi, Yutaka Tada, Kazushige Matsuura
    1984 Volume 10 Issue 3 Pages 308-314
    Published: May 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Sapwood samples of Sugi (Cryptomeria japonica) and Konara (Quercus serrata) were pyrolyzed in three batch-type reactors under an atmosphere containing no oxygen. The effects of the kind of wood, moisture content, pyrolytic temperature (873-1173 K), the heating rate of the sample (100-400 and more than 400 K. min-1) and the pyrolytic period of evolved smoke on the yields and the compositions of wood gas and distillate evolved and the yield of residual char were investigated. The species, shape and moisture of sample wood had little effect on the yields and compositions. When the sample was pyrolyzed at a high heating rate to higher pyrolytic temperature and the evolved smoke was retained at high temperature for an appropriate period, the yields of distillate and char became small, and the yield and the heat value of wood gas became large.
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  • Koichi Okumura, Ken-ichi Suga
    1984 Volume 10 Issue 3 Pages 315-322
    Published: May 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    In the kinetic study of the hydrolysis of amylose by glucoamylase, Hiromi et al. estimated the rate parameters (Michaelis constant Km, i and molecular activity K0, i) for amyloses of degree of polymerization (DP) in the range of 2 to 7.
    In this study, experiments were carried out to investigate the DP dependence of rate parameters for amyloses of DP ranging from 2 to 10. An empirical equation to calculate rate parameters for amyloses of DP ranging from 6 to 10 is presented based on the results obtained. It was confirmed that this empirical equation was also applicable to the hydrolysis of amyloses of DP ranging from 11 to 40, because experimental rate parameters were in good agreement with those calculated from the empirical equation for the hydrolysis of three kinds of amylose of DP above 11.
    The numerical solutions of the rate equations, in which parameters were calculated from the empirical equations, were in good agreement with the experimental data of conversion and molecular weight distribution in the degradation of amyloses of DPn 17.
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  • Ken-ichi Yoshie, Akira Suganuma, Hideo Yamamoto, Ryuichi Aoki
    1984 Volume 10 Issue 3 Pages 323-329
    Published: May 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    This paper describes the performance of a new pneumatic classifier based on the rapid classification principle. The following results were obtained.
    1) This classifier had a micron order cut size and its sharpness of classification χ= Dp75/Dp25 was about 1.50.
    2) By sucking a portion of clean air into the fine side, the recovery of fine particles was much improved.
    3) The cut size and sharpness of classification were not affected by feed concentration up to at least 0.3 kg/m3.
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  • Daisuke Konno, Naozumi Okita
    1984 Volume 10 Issue 3 Pages 330-336
    Published: May 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The behaviour of the liquid in a side-entry mixing tank is very difficult to observe, and to date the flow pattern and particle sedimentation process in such tanks have not been conclusively clarified.
    In the previous report the flow pattern and particle sedimentation process in a specially manufactured model mixer with a shaft entry angle θ=10° were observed and studied, with consideration also given to the effects of the handling conditions on the sweeping velocity of the mixer. Introducing sweeping-area formulas corresponding to the specified entry angle, the report also raised doubts concerning the sparse data presently available on these mixers.
    In the present study the entry angle was increased to θ = 20° and the flow variations in the mixing tank, i.e., the flow pattern and particle sedimentation process, were investigated. The results indicated that at θ=20° the effects of the depth of liquid in the mixer were very significant and that the liquid depth performed an important role as a sludge sedimentation preventive measure in the oil storage tank or in other parts of the full-scale mixer. A comparative analysis of the model as well as two and then three full-scale mixers was performed, and conclusions were drawn from the results of the study.
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  • Hiroshi Komiyama, Takuo Kataoka, Hakuai Inoue
    1984 Volume 10 Issue 3 Pages 337-342
    Published: May 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    In impregnation of catalyst support, the intraparticle distribution of catalytic component often affects the overall performance of the catalyst. Since hydrogen ion dominantly influences the interaction of catalytic component, with support, in the deposition mechanisms of ion exchange, adsorption and precipitation the distribution of hydrogen ion is of primary importance for control of the impregnation processes. In the present study, the interaction of alumina with acidic solutions is considered to be the neutralization of basic sites on alumina by acid in the solutions. The distribution of hydrogen ion during impregnation of support particles was analyzed on the basis of a model which incorporates intraparticle mass transfer processes as well as neutralization reaction, to show the formation of the pH boundary, that is, the narrow region of steeply changing concentration of hydrogen ion, from acidic to basic. The radial distribution of palladium deposit in the aluminum support, impregnated with PdCl2 solutions, was quantitatively elucidated by considering that palladium deposition occurs near the pH boundary.
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  • Norio Arai, Megumu Yusawa, Koutaro Hayashi, Masanobu Hasatani
    1984 Volume 10 Issue 3 Pages 343-350
    Published: May 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The energy recovery from surplus activated sludge to combustible gas product with partial combustion was investigated experimentally in a counter-flow moving bed, which has been recommended as one of the most promising energy recovery processes.
    The experiments were carried out within the following range of reaction conditions : air-fuel stoichiometric ratio m=0-1.0, inlet gas temperature Tg, i=600-800°C.
    The composition of the gas product produced by this sort of treatment is strongly affected and controlled by the air-fuel stoichiometric ratio and the inlet gas temperature. The main ingredients of the gas product are CO, CO2 and H2, which amount to above 80 vol% of the total gas volume on N2-free, dry basis.
    The gas yield based on the original dry mass of the sludge, G increases with increasing m-value, while the high heating value of the gas-product, Hh, has an increase relation against the m-value. In total, the product, G·Hh, which corresponds to the gaseous energy recovery yield, has a peak at some m-value depending on Tg, i. Within the range of the experimental conditions employed, the maximum energy recovery ratio from the dry sludge to the gas product form reaches about 35%. On the other hand, the energy recovery ratio to the total volatile matter including the gas has a peak near m=0.2, independently of Tg, i.
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  • Teruhiko Hoshino, Michio Uchiyama, Hiroshi Yukawa
    1984 Volume 10 Issue 3 Pages 351-358
    Published: May 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A liquid-liquid extractor equipped with 25 kHz ultrasonic horn through which feed (methyl-isobutyl ketone (MIBK), dissolved with butyric acid) can be dispersed into solvent (water) was newly developed and its performance and characteristics were investigated experimentally. The extraction rate in this extractor was remarkably enhanced because the interfacial contact area between feed droplets and solvent is conspicuously increased by emulsification with ultrasonic irradiation.
    The effects of residence time in the extractor, volumetric fraction of feed and input power of the ultrasonic generator on the capacity coefficient were experimentally investigated by use of MIBK-butyric acid-water as a sample, and an experimental equation representing the correlation between the capacity coefficient and these factors was proposed.
    Results showed that the capacity coefficient was about forty times that of the usual perforated-plate extraction tower for the same system. The over-all mass transfer coefficient, KR, was calculated with the capacity coefficient and the interfacial contact area, which was obtained from the drop size distribution measured by a photomicrograph. It was seen that KR obtained is slightly smaller than that of usual extractors and the conspicuous increase in the extraction rate depends mainly on the increase in the interfacial contact area. Furthermore, mass transfer from feed droplets to solvent was analyzed theoretically by assuming that a feed droplet is surrounded by a concentric spherical shell of solvent and that mass transfer by diffusion occurs in unsteady state, and the theoretical result was compared with the experimental ones.
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  • Norio Arashi, Yukio Hishinuma, Hayato Morita, Hiroshi Kuroda
    1984 Volume 10 Issue 3 Pages 359-365
    Published: May 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Gas-phase mass transfer of NO was studied using a rectangular channel composed of a plate-type catalyst on which NO reacts with NH3.
    The mass transfer rate was obtained by measuring the NO concentration distribution in the channel. It was found that the reaction rate on the catalyst was first-order in NO concentration. Using the first-order reaction rate, the concentration distribution of NO was calculated. The calculated values were in good agreement with measured values.
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  • Koji Nishimura, Sigeo Goto
    1984 Volume 10 Issue 3 Pages 366-371
    Published: May 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Since the diameters of conventional ion-exchange resin particles are less than 1 mm, the pressure drop may be very high in fixed-bed reactors packed with resin particles. Cylindrical pellets with diameters of 3-5 mm were made by mixing resin particles with binding powders and heating to 140°C. To compare catalytic activities of these resin pellets with those of resin particles, the hydrolysis of ethyl formate was carried out in a batch reactor.
    For the resin particles, the effect of diameter on catalytic activity could be explained by the usual effectiveness factor. On the other hand, the activity for the resin pellets was independent of the diameter of the resin pellets, although it was dependent on the diameter of the constituent resins (that is, raw resins used to make pellets). The decrease of activity was 16% for resin pellets independently of the diameter of the constituent resins. This means that the decrease of activity was not caused by the diffusional resistance in the void among the constituent resins, but by the blockage of the binder on the surface of constituent resins. These pellets are very useful as ion-exchange resins for packings of fixed beds because both the intraparticle diffusion resistance and the pressure drop can be reduced.
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  • Kazunari Ohgaki, Itsuro Tsukahara, Takashi Katayama
    1984 Volume 10 Issue 3 Pages 372-376
    Published: May 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Phase equilibria for the two binary systems octadecane-CO2 and octadecane-ethane were measured by use of a flow method at 25°C and 40°C for a fundamental study of supercritical fluid extraction.
    The two experimental temperatures were subcritical and supercritical temperatures for each solvent of the systems, and they were also below and above the melting point for octadecane. Therefore, appearances of various phase equilibria such as solid-liquid, solid-gas, gas-liquid and liquid-liquid equilibria had to be taken into consideration.
    It is examined from prediction of critical locus for each system which kind of equilibrium is corresponding to the phase equilibrium at each experimental condition. Thereafter, the phase-equilibrium data are satisfactorily correlated by use of the Soave-Redlich-Kwong equation of state.
    There is a certain pressure range where the solubilities of octadecane to high pressure fluids are suddenly decreased by a small increase of temperature from subcritical to supercritical states.
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  • Tatsuo Nishimura, Yoshiji Ohori, Yuji Kawamura
    1984 Volume 10 Issue 3 Pages 377-382
    Published: May 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Flow pattern and mass transfer characteristics around two cylinders in tandem arrangement were studied for a range of Reynolds number between 800 and 10, 000. The mass transfer coefficients were determined by the electrochemical method, and flow observations were performed by hydrogen bubbles and electric dye-production methods.
    The mean Sherwood number of the downstream cylinder varies with the pitch ratio at Reynolds numbers less than about 800 but not at higher Reynolds numbers. This variation is closely related to the behavior of separated shear layer from the upstream cylinder.
    A comparison of the Sherwood numbers for two cylinders and tube banks indicates that the local Sherwood numbers are different. This difference is due to the flow patterns, i.e., the mainstream in the tube banks is accelerated by the existence of the cylinders arranged perpendicular to the mainstream direction but the mainstream in the two cylinders has no acceleration.
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  • Masanori Inuzuka, Isao Saito, Takeshi Moriya, Ikuho Yamada, Setsuro Hi ...
    1984 Volume 10 Issue 3 Pages 383-388
    Published: May 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The rates of evaporation from the surface of the pure liquids EHS (di-2-ethylhexyl sebacate), EHP (di-2-ethylhexyl phthalate), and DBP (dibutyl phthalate) were measured under low pressure conditions, by using a pot still in which the evaporating and condensing surfaces are parallel with a distance L separating them.
    The following results were obtained.
    1) For all liquids, the observed evaporation rate G was smaller than the theoretical one from the kinetic theory of gases, G°.
    2) The difference -G tends to decrease as the pressure of residual inert gas, Pγ, de-creases at a constant temperature of evaporating liquid surface, tυ, and as tυ increases at a constant Pγ. It, however, approaches a limiting value.
    3) The following correlation for K (=G/G°) was proposed.
    ln1/K=0.0266Kn-0.660 (Pγ/Pυ)1.70+0.133Kn-0.260
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  • Masatoshi Minamizawa, Kazuo Endoh, Akira Ito, Koichi Asano, Koji Shima ...
    1984 Volume 10 Issue 3 Pages 389-407
    Published: May 10, 1984
    Released: November 12, 2009
    JOURNALS FREE ACCESS
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