JOURNAL OF CHEMICAL ENGINEERING OF JAPAN
Print ISSN : 0021-9592
Volume 36 , Issue 8
Showing 1-18 articles out of 18 articles from the selected issue
Transport Phenomena, Fluid Mechanics and Mixing
  • Noboru Otomo, Waldermar Bujalski, Alvin William Nienow, Koji Takahashi
    2003 Volume 36 Issue 8 Pages 905-911
    Published: 2003
    Released: June 05, 2004
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    Gas dispersion characteristics, i.e. ungassed and gassed power consumption, flow patterns and gas hold-up of the dual hollow blade disk turbines (6HB), which had been recently developed by a manufacturer to obtain a better gas dispersion performance than the traditional 6-bladed Rushton disc turbine (6DT), were investigated experimentally. The effect of impeller spacing in the dual 6HB impeller system on the unaerated and aerated power consumption was examined thoroughly.
    The gassed power consumption and gas hold up for the dual 6HB were compared with those obtained for the dual 6DT (radial flow impellers) and the dual Lightnin A315 (axial flow characteristics), of which performance has been also advanced recently. An enhancement of the gas handling capacity of the 6HB was achieved.
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  • Taejun Ok, Shinichi Ookawara, Shiro Yoshikawa, Kohei Ogawa
    2003 Volume 36 Issue 8 Pages 940-945
    Published: 2003
    Released: June 05, 2004
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    The experiments of immiscible liquid-liquid mixing in a stirred vessel were performed in order to relate the drop size distribution with impeller revolutional speed and to examine the applicability of a new formula of the drop size distribution presented by authors. The new formula based on an information entropy concept is composed of the product of the original distribution function and the realizable probability function derived under following two assumptions. First, the break-up of a drop occurs when the external force/energy exceeds the internal force/energy of the drop. Second, there is a limitation in the drop size which can exist in actuality.
    In the present work, ethyl malonate and water were adopted as a dispersed phase and a continuous phase, respectively. By setting the dilute volume fraction of the dispersed phase, the break-up of drops seems to be dominant while coalescence could be negligible. Impeller revolutional speed was varied from 210 to 300 rpm. A photographic method was utilized to measure the drop size.
    It is clarified that the new formula can express sufficiently the experimental data. Additionally, the drop size distribution for the number density derived from the new formula is also in agreement with the experimental data. The usefulness of the newly expressed formula is confirmed by applying it to other experimental data presented by other investigators.
    The parameter L as a mean size in the new formula is correlated with the impeller revolutional speed and it is made clear that L is in proportion to the impeller revolutional speed to the minus 1.2 power like the case of the Sauter mean drop size and the maximum drop size. The other parameter B as a coefficient is considered to be affected only by the ratio of the viscosity of dispersed phase to that of continuous phase of the liquid-liquid system.
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Catalysis, Kinetics and Reactor Design
  • Eun-Ho Lee, Yeong-Koo Yeo, Kyu Yong Choi, Hee-Young Kim
    2003 Volume 36 Issue 8 Pages 912-925
    Published: 2003
    Released: June 05, 2004
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    In the modeling of the solid-state polycondensation, the degree of dependence on the reaction step and diffusion step depends on the size of the prepolymer pellet. In other words, the model of the solid-state polycondensation processes should be a function of the size of the prepolymer pellet. In the present work a hybrid model based on the fuzzy techniques is proposed to represent simultaneously the characteristics of the reaction step and the diffusion step of the PET SSP process. The fuzzy technique was employed to take account of the “medium” particle size. The simulation results show the effectiveness of the hybrid model proposed. For the small pellet size, the hybrid model represents the behavior of the reaction-controlled step while the hybrid model depicts the behavior of the diffusion-controlled step for a large pellet size.
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  • Baitao Li, Xiaohong Li, Kenji Asami, Kaoru Fujimoto
    2003 Volume 36 Issue 8 Pages 932-939
    Published: 2003
    Released: June 05, 2004
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    Hydroformylation of 1-hexene has been investigated over cobalt supported on active carbon catalyst (10 wt% Co/A.C.) in a slurry phase reactor under low pressure (3.0 MPa). Added alcohols, such as methanol and other lower alcohols significantly promoted the reaction to realize a low-pressure process for hydroformylation at 3.0 MPa and 403 K, markedly giving acetals and aldehydes. Effects of operating variables on the CO conversion, yields of products and stability of the catalysts have been discussed in detail. The addition of a small amount of Ru (0.5 wt%) to the Co catalyst remarkably shortened the induction period and increased the catalytic activity. Compared with the corresponding homogeneous catalyst, the supported cobalt catalyst was observed to have good stability in the continuous feed system, showing constant CO conversion and yield of oxygenates.
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Separations
  • Wiwut Tanthapanichakoon, Noriaki Sano, Tawatchai Charinpanitkul, Nanta ...
    2003 Volume 36 Issue 8 Pages 946-952
    Published: 2003
    Released: June 05, 2004
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    The effect of electric field strength in a cylindrical corona discharge reactor to remove toluene from nitrogen and air is investigated using various wire-cathode diameters in the temperature range from room temperature to 400°C. When a thicker cathode is used at elevated temperatures, the required higher voltage and the accompanying gas expansion result in an increase in electron energy. When the reactor temperature is gradually elevated, the apparent removal efficiency decreases with temperature in the temperature range below 100°C because of the gas expansion. However, this tendency is reversed in the range above 300°C. Without the effect of gas expansion the removal efficiency per residence time indicates that the reaction rate to remove toluene increases with temperature from low temperature up to 400°C. In actual application to hot gas cleaning the use of a thicker cathode at high temperature such as 400°C without any cooling is recommended for high energetic efficiency.
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  • Akira Saito, Koichi Igarashi, Masayuki Azuma, Hiroshi Ooshima
    2003 Volume 36 Issue 8 Pages 953-958
    Published: 2003
    Released: June 05, 2004
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    Crystallization of p-acetanisidide (PAC) was carried out in the presence of p-acetoacetanisidide (APAC) as a solute analogue impurity. Addition of APAC into the supersaturated solution of PAC did not affect the structure of crystals of PAC, but affected the nucleation and crystal growth and also the morphology (crystal shape) of PAC crystals. APAC made the induction period before the beginning of precipitation of PAC crystals longer. The growth rate of PAC crystals was decreased. In particular, the growth of {100} surface was inhibited, resulting in the change of the crystal shape from plate-like to rod-like. Hydrogen bonding between PAC and APAC in solution was observed by analyzing the chemical shift of N-H hydrogen. As a result, the effects of APAC on the crystallization of PAC could be explained in terms of the hydrogen bonding between PAC and APAC molecules.
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  • Bin Zhao, Luis A. Guzman, Kaoru Ogawa, Kenji Shimizu
    2003 Volume 36 Issue 8 Pages 959-962
    Published: 2003
    Released: June 05, 2004
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    The growth rate of the (120) and (011) faces of an L-alanine crystal from aqueous solution was investigated in situ using an optical microscope system within a static and homogenous magnetic field from 0 to 5T. A clear inhibition in the growth rate of the two faces was observed in a magnetic field. This growth inhibition effect increased with an increasing magnetic field intensity. The growth inhibition induced by the magnetic field was attributed to a lower mass transfer, which was assumed to be caused by a decreased flow velocity of buoyancy convection and crystal orientation in a suspending state in the solution.
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  • Yoshitaka Yamamoto, Takeshi Komai, Ji-Ho Yoon, Seong-Pil Kang, Shinsuk ...
    2003 Volume 36 Issue 8 Pages 971-978
    Published: 2003
    Released: June 05, 2004
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    The feasibility of H2S removal from gas mixture using hydrate formation was examined theoretically as well as experimentally. The hydrate formation conditions for a three-component gas mixture of CO2, He and a small amount of H2S (30%-CO2, 70%-He and 50 ppm-H2S) were determined using a high-pressure equilibrium cell by a visual observation method. It was found that He only plays a role in gas diluents, whereas H2S decreases the dissociation pressures of gas hydrate slightly. A fugacity-based model was used to demonstrate the characteristics of H2S removal by hydrate formation. The advantage of a gas hydration process for H2S removal was described in terms of removal efficiency. Upon calculation with our model, the removal efficiency by hydrate formation ranges from 8 to 11 and is approximately 3 or 4 times greater than that by liquid water scrubbing.
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  • Ryosuke Maeda, Michiaki Matsumoto, Kazuo Kondo
    2003 Volume 36 Issue 8 Pages 979-984
    Published: 2003
    Released: June 05, 2004
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    PAN (1-(2-pyridylazo)-2-naphthol) was immobilized into admicelles of nonionic surfactant (Triton X-100) on silica gel. In this work, the interesting interfacial phenomena in preparation of a metal uptake system using the admicelles were investigated. It was clear that adsorption of micelles of Triton X-100 was significantly affected by both kind and amount of alcohol. The adsorption amount of Triton X-100 micelles increased with the following order: methanol > ethanol > 2-propanol > 1-propanol > tert-butanol. The order was well correlated by the octanol–water partition coefficients of these alcohols. The stability of the system was examined under various environmental factors for its practical use. The system was very stable under normal conditions, e.g. temperature, 298–318 K; time course, 0–52 hours; pH, 2.5–12.0. Although the system was not stable under a severe condition of pH (<2.5 and >12.0).
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  • Norihito Doki, Masaaki Yokota, Hiroaki Nakamura, Shigeko Sasaki, Noria ...
    2003 Volume 36 Issue 8 Pages 1001-1004
    Published: 2003
    Released: June 05, 2004
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    Adipic acid was crystallized by cooling in a batch crystallizer. At low seed loadings, the product crystal size distribution (CSD) was bi-modal because of enormous secondary nucleation. However, at high seed loadings, it became uni-modal, where the crystallization was dominated by seed growth with practically no secondary nucleation. Enough seeding was thus effective in suppressing nucleation during batch crystallization. The mean mass size of the product crystals obtained at high seed loadings agreed with that calculated by a simple mass balance assuming growth-dominated crystallization with no change in the number of crystals during operation and no residual supersaturation towards the end of batch. The products obtained, i.e., grown seeds, were not well faceted but rounded, probably because of abrasion caused by mechanical impact induced by agitation.
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Particle Technology and Fluidization
  • Isao Kobayashi, Yosuke Iitaka, Satoshi Iwamoto, Shoji Kimura, Mitsutos ...
    2003 Volume 36 Issue 8 Pages 996-1000
    Published: 2003
    Released: June 05, 2004
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    Using a novel microchannel (MC) emulsification method, we are able to form microspheres (MS) with narrow size distributions. MC emulsification and subsequent solvent evaporation were performed to prepare micron-scale lipid MS with relatively narrow size distributions. The experimental systems with hexane as the dispersed-phase solvent stably formed oil-in-water (O/W)-MS with average diameters of 10–11 μm and coefficients of variation below 8% from the uniformly sized channels. The sodium dodecyl sulfate- and pentaglycerol monolaurate-containing systems performed the successful MC emulsification. Lipid MS with average diameters of 1–3 μm and coefficients of variation of about 20% were obtained through successive solvent evaporation of the formed monodisperse O/W-MS composed of 0.1–1.0 vol% tripalmitin in hexane. The diameters of the resultant lipid MS corresponded well to their estimated diameters, regardless of the tripalmitin concentration.
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  • Fukuji Ebihara, Satoru Watano
    2003 Volume 36 Issue 8 Pages 1012-1015
    Published: 2003
    Released: June 05, 2004
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    This paper discusses a process for making a granular detergent with a high content of active surfactant and favorable solubility by using various ingredients. This process contains three steps to develop the high active surfactant and soluble granular detergent. The first step was to grind (de-agglomerate) secondary alkyl sulfate (SAS) particles with inorganic material such as silica powder in a high shear mixer. After that, the ground SAS powders were agglomerated with a nonionic surfactant to produce granular detergent particles. These agglomerates were coated with inorganic materials (zeolite or silica). The coated agglomerates provided a significantly improved solubility of the granular detergent as well as providing high active surfactant and better physical properties (e.g., higher bulk density, better flow ability, etc.). In this study, the feasibility to make better performance of granular detergent by using SAS particles was discussed.
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Process Systems Engineering
  • Yool Kwon Oh, Seul Hyun Park
    2003 Volume 36 Issue 8 Pages 985-990
    Published: 2003
    Released: June 05, 2004
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    A heat flow was measured in the absence of and in the presence of acoustic streaming. The streaming produced by ultrasonic transducers was visualized by a particle imaging velocimetry (PIV) and an infrared thermal camera. The experimental results revealed that acoustic streaming could accelerate the melting process as much as 2.5 times, compared to the rate of natural melting (i.e., the melting without acoustic streaming). In addition, temperature and Nusselt numbers over time provided conclusive evidence of the important role of acoustic streaming on the melting phenomena of the phase change material (PCM).
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  • Junghui Chen, Yuezhi Yea
    2003 Volume 36 Issue 8 Pages 1005-1011
    Published: 2003
    Released: June 05, 2004
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    A modified pole placement controller on the basis of a dynamic neural network is developed for controlling nonlinear multi-inputs and single output (MISO) processes. Using process data, this dynamic network composed of several local single-input and single-output (SISO) neural network models is trained to model general nonlinear MISO processes. At each time step each local neural model is linearized to produce the linear transfer functions. Hence, the original MISO control problem is decomposed into several SISO linear control problems. As a consequence, the well-established pole placement design technique for linear systems can be implemented directly. Like the indirect self-tuning control design, the control synthesis algorithm is adaptive when the linear model is extracted from the nonlinear neural model at each sampling instant. In the end, a pH neutralization system is used to verify the control performance of the proposed method.
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Biochemical, Food and Medical Engineering
  • Yoichi Kumada, Masumi Maehara, Naoki Minami, Shigeo Katoh
    2003 Volume 36 Issue 8 Pages 926-931
    Published: 2003
    Released: June 05, 2004
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    A liposome immunoblotting assay utilizing an enhanced chemiluminescent reaction was developed by means of substrates permeable through the phospholipid membrane for rapid, automatic and sensitive detection of analytes. In the enhanced chemiluminescent (ECL) reaction, the total amount of chemiluminescent light increased by means of substrate solutions containing several surfactants, such as Tween 20 and TritonX-100. In this liposome immunoblotting assay, clear chemiluminescence signals could be detected from blotted circles on the membrane and increased with the concentration of Tween 20 (0–1%) in the substrate solutions. The sensitivity in the liposome immunoblotting assay was 20 times that of conventional assay using HRP-conjugated antibody, and 2 pg of human IgM as a model analyte could be detected under optimal conditions. Thus, the liposome immunoblotting assay utilizing the ECL reaction has a high sensitivity among other immunoblotting assays and is useful for rapid detection of trace amounts of analytes and low affinity interactions in micro-array and other detection formats.
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Safety, Environment and Energy
  • Masamichi Akimoto, Masahiro Ishikawa, Masahiro Sato, Katsuhiro Washio
    2003 Volume 36 Issue 8 Pages 991-995
    Published: 2003
    Released: June 05, 2004
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    The hydrothermal dechlorination and denitrogenation of fuel oil derived from municipal waste plastics (kerosene fraction; Cl content = 62 ppm, N content = 1150 ppm) was investigated under subcritical liquid-phase conditions using a small SUS316 stainless steel continuous, packed-bed reactor. Although these two reactions took place in pure water, they proceeded much more readily in aqueous solutions of NaOH. For example, the nitrogen content in the oil decreased to 73 ppm upon processing with 0.10 mol/L NaOH for 5.50 min at 300°C and at the reactant weight feed ratio of unity. The chlorine content in the oil decreased to 2 ppm as a result of the alkaline hydrothermal processing. Both rates of these two reactions could well be described in terms of a homogeneous first-order reaction kinetics with a tentative equilibrium heteroatom content under the hydrothermal processing conditions used.
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  • Sea Cheon Oh, Hyun Chul Jun, Hee Taik Kim
    2003 Volume 36 Issue 8 Pages 1016-1022
    Published: 2003
    Released: June 05, 2004
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    The pyrolysis kinetics of styrene-butadiene rubber (SBR) was studied by the kinetic model which accounts for the thermal degradation of polymer at any time. The kinetic analysis was performed by a conventional nonisothermal thermogravimetric (TG) technique at several heating rates between 10 and 50 K/min in a nitrogen atmosphere. To verify the effectiveness of the kinetic analysis method used in this work, the kinetic analysis results were compared with those of various analytical methods. The TG data were also compared with values calculated by using the kinetic parameters obtained from this work. It was found that the kinetic analysis method used in this work gave the reliable kinetic parameters of SBR pyrolysis.
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General Research and Others
  • Tatsumi Yamamoto, Masanori Tanaka, Hiroyuki Kawasaki
    2003 Volume 36 Issue 8 Pages 963-970
    Published: 2003
    Released: June 05, 2004
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    The effects of non-ionic surfactants added to the oil phase and to the outside water phase, on the oil droplet diameters in O/W emulsions and on the W/O emulsion drop diameters in W/O/W emulsions, respectively, were investigated experimentally. Sauter mean diameters of the oil droplets in O/W emulsions, and of the W/O emulsion drops in W/O/W emulsions, had minimum values at a specific concentration of surfactant in the outside aqueous phase. The effect of the surfactant concentration on the drop diameter corresponded to that of the interfacial stretching forces which were measured with the aid of a ring method using a Du Noüy type platinum ring.
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