JOURNAL OF CHEMICAL ENGINEERING OF JAPAN
Print ISSN : 0021-9592
Volume 21 , Issue 5
Showing 1-20 articles out of 20 articles from the selected issue
  • KAORU ONOE, NAOKI FURUKAWA, TADASHI SHIROTSUKA
    1988 Volume 21 Issue 5 Pages 451-456
    Published: October 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    An attempt was made with rare earth intermetallic compounds to prepare highly active catalysts by low-temperature oxidation. CeNi5 was chosen as the starting material, because works on LaM5 have shown that surface area increase and Ni crystallite growth are closely related to oxidation rate, and because the Ce oxidation rate is much higher than that of La.
    It was found that low-temperature oxidation of CeNi5 was accompanied by an increase in surface area without the growth of Ni crystallites. The reaction rate of CO hydrogenation per Ni weight was about 500-fold higher for Ni/CeO2 than for Ni/La2O3 at 535 K. This was connected with increased Ni surface area (180-fold) and high turnover frequency (2.8-fold). Moreover, C2 and C3 products increased with increasing conversion of Ce oxidation.
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  • YASUHARU AKAGI, KENJI OKADA, TOSHIHISA DOTE, NAOYA YOSHIOKA
    1988 Volume 21 Issue 5 Pages 457-462
    Published: October 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    Separation of oil droplets in oil-in-water mixture was studied by using a glass fiber bed coalescer. Fuel oil (B-type) was used as the oil phase and was dispersed in water at a concentration of 1000 ppm. Glass fibers of 5.3 μm and 19μm diameter were used as packing media. The relationship between the pressure drop across the bed and the oil holdup in the bed at steady state was examined under several experimental conditions and a correlated equation for the relationship was presented. The equation could predict not only the pressure drop at steady state but also those at unsteady states. A new correlation equation for separation efficiency of oil droplets was proposed.
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  • SHIGEAKI INADA, YOSHIKI MIYASAKA, KENJI SAKAMOTO, KEIJI HOJO
    1988 Volume 21 Issue 5 Pages 463-468
    Published: October 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    Heat transfer of a drop impinging on a heated surface is considerably influenced by liquid-solid contact and the formation of a vapor film accompanying it. In this research, the authors report experimental results regarding the thickness of the vapor film formed between the drop and the heated surface, its fluctuation, and liquid-solid contact state by application of laser optical measurement to solid-vapor-liquid interfaces.
    Vapor film thicknesses below 5 μm for high drop subcooling (88 K) and above 10 μm for low subcooling (2 K) were recognized at heated surface temperatures above 420° in the latter half of the residence time.
    In addition, the boiling mechanism of a unique miniaturization phenomenon was proved.
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  • PETER L. SILVESTON, ABIOLA J. KEHINDE, ROBERT R. HUDGINS
    1988 Volume 21 Issue 5 Pages 468-476
    Published: October 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    Heterogeneity of adsorbent surfaces is not taken into account in models now used in the application of pulse chromatography to the measurement of kinetics and transport -properties. Heterogeneity can be allowed for by assigning sites to groups or types and adding terms to the normal model for each group. This formulation leads to a nonlinear model, and additivity means that resolution of the group parameter requires a large amount of data. A lumping model is also examined: this approach also yields a nonlineaf model, but data requirements could be less. Rate and equilibrium constants were measured for ethylene adsorption on activated alumina by pulse chromatography. Temperature-programmed desorption measurements for the same system indicated surface heterogeneity. Of the two or possibly three types of adsorption sites on the alumina surface, only the low-temperature sites participated in the pulse chromatography measurement.
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  • KIYOMI AKITA, TATSUYA OKAZAKI, HIROSHI KOYAMA
    1988 Volume 21 Issue 5 Pages 476-482
    Published: October 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    Gas holdups and friction factors were measured for gas-liquid parallel two-phase flow in an air-lift bubble column.
    Velocities of gas and liquid, liquid viscosity, and surface tension were varied. The results were correlated with dimensionless equations.
    As to the gas holdups (εG), Akita-Yoshida''s equation1) for batchwise processes was modified to the following form to suit continuous parallel gas-liquid flow operation:
    εG(1-εG)-4=0.20(gD2ρL/γ)1/8(gD3/v2L)1/12(UGL/(gD)1/2)
    As to the friction factors (f), the following correlation was proposed.
    f=0.0468(UL/(gD)1/2)-1.1ε0.5G
    These equations are useful for estimations of gas holdups, distribution of gas holdup along the column height, and liquid circulation velocities between a riser and a downcomer in an air-lift bubble column.
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  • TOSHIMITSU INOMATA, KATSUAKI ONOGI, YOSHIHIKO NAKATA, YOSHIYUKI NISHIM ...
    1988 Volume 21 Issue 5 Pages 482-489
    Published: October 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    The increasing variety of variants in products and/or raw materials in a multiproduct batch process causes frequent alterations of the system configuration and the operational policies. Therefore, the simulation system for batch processes must be flexible enough to deal easily with the alterations. This paper presents a rule-based simulation system for discrete event systems, e.g. batch processes, which has the capability to examining the validity of a simulation model. The model we employ is composed of system state and events. The basic unit for representing the system state is the frame and the behavioral description of the event is provided by the if-then rule. To prevent the model from being incomplete, the simulation system clarifies the causal relationship between rules and frames and detects the rules which are never executed or which have possibilities of conflict. The relationship is also utilized for executing efficient simulation. The model employed deals easily with rapid alterations of the simulated system because it takes advantage of the modularity of a rule.
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  • HARUMI MATSUZAKI, ISAO OOKOUCHI, HIDEAKI KUROKAWA, KATSUYA EBARA, SANK ...
    1988 Volume 21 Issue 5 Pages 490-492
    Published: October 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    Effects of evaporation temperature on the formation of water marks left on a Si wafer were studied using membrane-distilled water and ultrapure water.
    The main constituent of water marks from membrane-distilled water was found to be liquid hydrocarbon, with some C = C bonds present, and when evaporation velocity was greater than about 20 kg/(m2•h) evaporation could take place without marks formation. Water marks from ultrapure water had a higher boiling point than those from membrane-distilled water and were left on a Si wafer even when the water was evaporated at a velocity of about 20kg/(m2• h).
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  • TERUO TAKAHASHI, SATORU KASENO, MASAHIRO KOMOTO, SEIGO SHIBATA
    1988 Volume 21 Issue 5 Pages 493-497
    Published: October 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    The lateral mixing of solid particles in a centrifugal fluidized bed in which the rotation axis is horizontal was investigated from the unsteady-state behavior of tracer particles. The lateral mixing characteristics were analyzed by a diffusion model identical to that for a conventional fluidized bed.
    The lateral dispersion coefficient of particles was affected by variables such as gas velocity, rotational speed of the rotor, particle diameter, bed height and minimum fluidized velocity. From the experimental results an empirical equation for the coefficient was obtained. Its value for a centrifugal fluidized bed was smaller than that calculated from empirical equations for a conventional fluidized bed, because of smaller bubble diameter and bed height, centrifugal force, and the like.
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  • TING-CHIA HUANG, LAN-T''AI CHO
    1988 Volume 21 Issue 5 Pages 498-503
    Published: October 20, 1988
    Released: April 19, 2006
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    A model was proposed by simplifying the surface diffusion model. In addition, three models-the simplified model, the quadratic driving force model and the surface diffusion model-were used to analyse experimental data of the adsorption of p-nitrophenol and p-chlorophenol on anion exchange resin (lonac AFP-329) in a batch adsorber. The simplified model gives a better approximation to the surface diffusion model than does the quadratic driving force model. Moreover, from the experimental data the result also shows that the surface diffusion coefficient varies linearly with q1/n.
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  • SUGENG WINARDI, SHUYA NAKAO, YOICHI NAGASE
    1988 Volume 21 Issue 5 Pages 503-508
    Published: October 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    Very low frequency fluctuations in the velocity signal from several seconds to several minutes in scale are usually observed in agitated vessels. It is shown in this work that these fluctuations result from the abrupt replacement of the flow pattern in the vessel, even in part. Pattern recognition studies of the flow in the impeller region of a paddle were carried out, using high-speed VTR. The results showed that the flow between blades is characterized into five patterns which are replaced one after another. They are classified into the discharge and the cross-pass types of flow. The latter means that flow passes between impeller blades, upwardly or downwardly. The lifetime of the discharge flow type was three times that of the cross-pass flow type. The velocity distributions of the discharge and cross-pass flow types estimated from visualized pictures were quite different from each other and were different from the average distributions obtained by LDV. When the cross-pass pattern had developed over the whole region between blades, a horizontal figure-eight pattern of flow developed in the entire vessel with abrupt reduction of the torque.
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  • TAKASHI NAKAYAMA, HIROSHI SAGARA, KUNIO ARAI, SHOZABURO SAITO
    1988 Volume 21 Issue 5 Pages 509-515
    Published: October 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    An expression for the excess Gibbs energy of expandable liquid mixtures, such as liquefied gas mixtures, is obtained by considering the effect of molar volume change on the structure of a solution. A new equation is derived through the introduction of two limiting states: the close-packed and hypothetical expanded states. From this model, the deviation of the excess Gibbs energy from the close-packed state is determined by hole fraction and solution structure parameter. The model, which requires only binary parameters, was tested on vapor-liquid and liquid-liquid equilibria of various mixtures including liquefied gas mixtures, and gave better data representation than the UNIQUAC model.
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  • GEUN S. LEE, SANG D. KIM
    1988 Volume 21 Issue 5 Pages 515-521
    Published: October 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    From the statistical analysis of pressure fluctuations, the hydrodynamic properties in a turbulent fluidized bed of glass beads (dp: 0.362mm) have been determined in a 0.1m-ID × 3m high Plexiglas column. The statistical properties such as mean amplitude, fluctuation interval, standard deviation, skewness and flatness of pressure fluctuations have been utilized to determine the transition velocity from the bubbling to turbulent flow regimes in a fluidized bed. The obtained transition velocities from these methods were found to have very similar values. In the turbulent flow regime, the mean amplitude, fluctuation interval, standard deviation and flatness of pressure fluctuations decreased with an increase in gas velocity. By contrast, the skewness of pressure fluctuations increased with gas velocity.
    The data of the present and previous studies on transition velocity from bubbling to turbulent flow regimes in terms of Reynolds number have been correlated with Archimedes number.
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  • AKIRA YASUNISHI, MIKI FUKUMA, KATSUHIKO MUROYAMA
    1988 Volume 21 Issue 5 Pages 522-528
    Published: October 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    The wall-to-liquid mass transfer coefficient, kw, was measured for both surfaces of a coaxially immersed tube and a column wall in packed and fluidi/ed bed systems with gas-liquid concurrent upflow. Supplementary measurements of kw were carried out in openpipe liquid flow, gas-liquid two-phase upflow and packed and fluidized beds with single liquid flow.
    The value of kw in the three-phase fluidized bed increased with increasing gas flow rate, deviating from the value in the liquid-solid fluidized bed and approaching the value in the gas-liquid two-phase upflow, while it passed through a maximum value with respect to the liquid flow rate. The value of kw in the packed-bed operation increased with increasing liquid flow rate and with increasing gas flow rate. The values of kw for the inner tube and the column wall were shown to agree with each other.
    The values of kw in all the gas-liquid, liquid-solid and gas-liquid-solid systems examined were correlated well by a unified equation in terms of the energy dissipation rate per unit mass of liquid.
    An analogy existed between wall heat transfer and wall mass transfer in all the multiphase flow systems examined.
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  • MASAMI FURUUCHI, ATSUO IKEUCHI, TAKAHIRO FUKAGAWA, KEISHI GOTOH
    1988 Volume 21 Issue 5 Pages 528-533
    Published: October 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
    Experimental investigations are made into the electrical conductivity of suspensions of non-conducting particles of various shapes. Theoretical relations so far available for spheroidal particle systems are tested and the Fricke equation is used for determining particle shape as the aspect ratio of an equivalent spheroid. The electrical conductivities of suspensions of disks and cylindrical particles are obtained experimentally. The effect of the shape distribution on the conductivity of suspensions is also discussed.
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  • SHIMIO SATO
    1988 Volume 21 Issue 5 Pages 534-535
    Published: October 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
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  • MASAO SUDOH, TAKAMASA KODERA, HARUYOSHI HINO, HIROSHI SHIMAMURA
    1988 Volume 21 Issue 5 Pages 536-538
    Published: October 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
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  • ISAMI YOSHIFUKU
    1988 Volume 21 Issue 5 Pages 538-541
    Published: October 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
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  • YOSHIYUKI YAMASHITA, MUTSUMI SUZUKI, KOICHI KAMBE
    1988 Volume 21 Issue 5 Pages 541-543
    Published: October 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
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  • K. TOJO, Y. W. CHIEN, C. C. CHIANG, P. R. KESHARY
    1988 Volume 21 Issue 5 Pages 544-546
    Published: October 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
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  • MAW-LING WANG, CHANG-PING TSAI, JING-JER JWO
    1988 Volume 21 Issue 5 Pages 547-550
    Published: October 20, 1988
    Released: April 19, 2006
    JOURNALS FREE ACCESS
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