KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 23 , Issue 4
Showing 1-26 articles out of 26 articles from the selected issue
  • Yoshitomo Hanakuma
    1997 Volume 23 Issue 4 Pages 461-469
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Technologies of detecting process abnormal signals in fault diagnosis using multi-detection systems for industrial use have been developed in an industrial petrochemical plant. In this paper, the design and application of a multi-detection system using an adaptive digital filter, wavelet analysis, attractor analysis, Bayesian statistical inference, white noise testing and hypothesis testing are presented.
    The future tasks of the multi-detection system design of process abnormal signals for industrial use are discussed.
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  • Tohru Nagasako, Hiromitsu Yamaguchi, Yoshihiro Matsumoto, Tsuyoshi Oki ...
    1997 Volume 23 Issue 4 Pages 470-476
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Polymerization processes use two kinds of reactor. One is a continuous reactor and the other is a batch reactor. Both are highly nonlinear and unstable. Thesefore safe operation is important. In a polymerization reactor, raw materials and additives are mixed under specified operating conditions to produce polymer having desired properties and an operator must monitor reactor conditions, especially to avoid runaway reactions.
    In batch processes, many operation steps are required, and operators have to monitor a number of checkpoints for several processes. Operator support systems, such as diagnosing errors in operation or faults and monitoring process conditions are very helpful for balancing workload and for safe operation.
    An accurate and widely supported system is developed based on an expert system with a mathematical reactor model to estimate reactor conditions precisely.
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  • Akira Saji, Yukihiro Takamura, Hidetomo Noda, Fujio Watanabe, Hitoki M ...
    1997 Volume 23 Issue 4 Pages 477-481
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The performance of H2O-PSA with Zeolite 3A as adsorbent was examined for the dehumidifing of flue gas at the first stage of a CO2 separation system with CO2-PSA and cryogenic separation. Zeolite 3A displaced with K+ at the site of the hydrogen ion has shown performance higher than active alumina with respect to the decrease in loss of CO2 in flue gas through H2O-PSA as well as the dehumidification of flue gas. In addition, it has been shown that there is a possibility of operating the H2O-PSA with low power by applying the purge with off-gas from CO2-PSA.
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  • Akira Saji, Hidetomo Noda, Yukihiro Takamura, Fujio Watanabe, Hitoki M ...
    1997 Volume 23 Issue 4 Pages 482-490
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A system of CO2 disposal, in the form of CO2 clathrate, in the deep ocean has been proposed in order to prevent the green house effect caused by increase of CO2 in the atmosphere. A process consisting of both the production of CO2 clathrate and its in-situ consolidation is proposed for applying to the above CO2 disposal system as an efficient process to obtain faster sedimentation of CO2 clathrate blocks in the ocean and to prevent adverse environmental effects in the deep ocean. The process is experimentally analyzed and evaluated. It was confirmed that the CO2 clathrate block is formed in the in-situ consolidation vessel through Compressing the CO2 clathrate powders produced in the reaction vessel. Furthermore, it was confirmed that the clathrate block settled smoothly in artificial sea water under deep ocean conditions and that the process is one suitable method for application to the system. In addition, analysis of the consolidation mechanism was performed for the CO2 clathrate. And it was found that consolidation proceeds via two step, i. e., the first one at low pressure shows the decrease in the spacing volume between the colonies consisting of CO2 clathrate powders with pressurizing, and the second one at high pressure shows the breaking down step of the colonies. The boundary pressure between the first and second steps is ca. 2.3 MPa. Also, the dissolution rate of CO2 clathrate block was measured CO2-free artificial sea water and the rate was ca. 1.9 m/s at maximum.
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  • Masatoshi Yoshida, Hideyuki Watanabe, Shigeru Matsumoto
    1997 Volume 23 Issue 4 Pages 491-497
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A model based feedback control algorithm is developed for parabolic type distributed parameter systems in two-dimensional space. The model used is a fully decoupled state space model which is obtained by applying the finite integral transform technique to the phenomenological model of a process. A state feedback controller is designed for the state space model by using a Kalman filter as an observer. The proposed method is applied to control of temperature distribution in a two dimensional heat conduction process. It is demonstrated that the temperature distributions can be accurately estimated by use of a small number of sensors and controlled satisfactorily even when some model error exists.
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  • Yasuhiro Imamura, Satoji Kobayashi, Hikoji Inazumi
    1997 Volume 23 Issue 4 Pages 498-504
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The characteristics of gas-liquid flow and mass transfer for absorption of carbon dioxide are experimentally investigated by using a vertical ejector with water jet.
    The flow patterns in the throat and diffuser are regarded as approximately bubbly flows under the experimental conditions. The gas entrainment rate caused by the vertical flow liquid jet increases with increasing liquid flow rate. The entrainment rate is shown as a function of the liquid flow rate, the geometric shape factor of the nozzle and Froude number. The empirical correlation obtained in this work can predict the entrainment rate within an error of ± 15%.
    The longitudinal distribution of static pressure in the apparatus is investigated. It is confirmed that the static pressure with gas flow is different from that without gas flow. The longitudinal distributions of the volumetric coefficient of mass transfer in the liquid phase, kxa, are investigated. It is found that kxa shows a maximum value and increases with increasing molar flow rates of gas and liquid for the single nozzle case.
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  • Tadafumi Adschiri, Osamu Sato, Katuhiko Machida, Norio Saito, Kunio Ar ...
    1997 Volume 23 Issue 4 Pages 505-511
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The possibility for chemical recycling of PET via the recovery of terephthalic acid from decomposition of PET with supercritical water is investigated. PET decomposes to terephthalic acid and ethylene glycol, which are raw materials for PET, in supercritical water and the yield of terephthalic acid reaches 91% with purity of 97% under the conditions of 673 K, 40 MPa and reaction time of 12.5 min. Reaction temperature influences the decomposition rate of PET. It takes 90 min for 90% terephthalic acid recovery at 573 K. Increasing reaction pressure is effective for suppressing char formation or carbon dioxide production during decomposition.
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  • Satoshi Iwasaki, Yoshiaki Okusako, Minoru Miyahara, Morio Okazaki
    1997 Volume 23 Issue 4 Pages 512-518
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The single-electrode capacitance of a nano-porous carbon electrode used as an electric double layer capacitor was measured. The charged state of the electrolyte ion was discussed from the results. Single-electrode capacitance was not proportional to the specific surface area of the electrode. This implies that the whole surface of the electrode is not effective for the formation of an electric double layer. It is considered that edge orientation of the carbon structure would give a dominant contribution to capacitance.
    For measurements with aqueous solutions of various electrolytes, capacitance was about the same value for each salt compound. For aqueous acid solution, on the other hand, capacitance was twice to three times as large as that for salt compounds. This difference, however, became negligibly small if the concentration of electrolyte solution was lowered. Taking account of the hydrated ionic radius of each ion, it was considered that ions in salt solutions attach onto carbon electrodes together with hydration water molecules. Higher capacitance in acid solution of higher concentration was interpreted in connection with proton transfer, with which charged particles in acid solution could stay closer to the electrode surface.
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  • Satoshi Iwasaki, Hideki Kanda, Minoru Miyahara, Morio Okazaki
    1997 Volume 23 Issue 4 Pages 519-525
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Single-electrode transient behavior was measured mainly during the discharging process for a model cell of electric double layer capacitor with nano-porous carbon electrodes and reference electrode. Apparent conductivity in the cell, which we call “effective conductivity, ” is determined with approximation of current in transient behavior to a one-dimensional electrophoretic model. A comparison of effective conductivity with conductivity of bulk solution suggests an interesting mechanism of transfer of electrolyte ions.
    The difference in transient behavior between various electrolyte ions was not conspicuous in spite of distinctive differences in conductivity of each bulk solution. The large pore diameter of the carbon electrode results in rapid transient behavior and such an electrode should be suitable for rapid charge and discharge. The effect of origin of carbon electrode is found to be significant to bring considerable differences in discharge rate. However, the difference in transient behavior that was caused by materials for carbon electrode becomes smaller for lower concentrations of electrolyte solution. Effective conductivities for all experiments do not directly reflect conductivities of bulk solution of each electrolyte. This implies that electrolyte ions are transported based not only on the electrophoretic effect, but also on a mechanism similar to surface diffusion.
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  • Choko Kamata
    1997 Volume 23 Issue 4 Pages 526-531
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Previous studies on boiling heat transfer by impinging jets are mainly concerned with the impinging point by using small heat transfer surfaces of about 20 mm.
    An experimental study of the boiling heat transfer to an impinging water jet on a massive hot block is made.
    The upward heating surface is made of copper. Its diameter and nozzle diameter are 80 mm and 2.2 mm, respectively.
    The velocity of the impinging jet was varied from 0.6 to 2.1 m/s. Saturated water normally impinged on the heating surface, flowed radially, and subsequently dispersed into the atmosphere.
    The present study clarifies that heat transfer characteristics vary with the temperature of heat transfer surface, and also with the distance from the impinging point.
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  • Itaru Kato, Takeshi Sasaki, Satoru Kato, Kunio Nagahama
    1997 Volume 23 Issue 4 Pages 532-540
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The effects of pre-adsorption of NO2 on the enhancement of the adsorption of NO on H-type zeolite are investigated to develop a fixed-bed adsorption process for removing low concentration NO effectively. The concentration of NOx in the effluent gas from a zeolite column was analyzed by a chemiluminescence method, where the concentration of the NO at the inlet was adjusted to be between 0 to 1, 000 ppm.
    It was found that the amount of NO adsorbed increases thirty to forty times when NO2 is preadsorbed on H-type zeolite. The amount of NO adsorbed depends on the concentration of NO2 Pre adsorbed, the concentration of NO supplied, and column temperature. 100% removal of No can be achieved when the concentration of NO is lower than 1, 000 ppm and that of NO2 at the inlet during pre-adsorption is lower than 300 ppm. The extent of NO removal was similar for each diluent gas, nitrogen or helium. Based on these results, an adsorption process was proposed for the removal of NOx.
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  • Masatoshi Yoshida, Takahiro Hamada, Yuji Houmura, Shuji Obi, Shigeru M ...
    1997 Volume 23 Issue 4 Pages 541-547
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A new algorithm for on-line estimation of moisture distribution in non-hygroscopic granular materials is presented. The dynamics of moisture movement in granular materials under drying are frequently modeled by non-liner diffusion equations. By application of Kirchhoff transform, the equations are linearized and then approximated to a lumped parameter system (LPS) model by means of the finite integral transform technique. Kalman filter is applied to the LPS model to estimate moisture distribution. The results show that the moisture distribution can be estimated satisfactorily from measurements of surface and average moisture content.
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  • Kazuyo Kikuchi, Miho Uchida, Toshiaki Yoshioka, Akitsugu Okuwaki
    1997 Volume 23 Issue 4 Pages 548-554
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Reduction of sodium nitrate solution by lead drops with wet-ballmilling is studied in order to remove concentrated NO3- from wastewater. Metal oxides forming on the lead drops surfaces in a ballmill reactor was continuously removed by inter-ball contacting
    In the 5-80°C temperature range, initial concentration of NaNO3 0.05-0.1 M, and ballmill rotation speed, ω, 80-180 rpm, NO3- is rapidly reduced to NO2-, then slowly to N2 and NH3. NO3- is reduced to NO2- 32-100% in 10 h, but the reduction rate of NO2-is very slow, so the maximum percentages of N2 and NH3 from NO2- are only 6 and 10 %, respectively.
    Above 40°C, NO3- is reduced under zero-order reaction and NO2- is formed corresponding to the reduction stoichiometry. The reduction rate is proportional to ω1/2 [rpm1/2], and the apparent activation energy is 27.5 kJ·mol-1, but independent of the NO3- concentration. These results suggest that the rate determining step is the peeling of PbO layers on the particle surface. Below 25°C, the reduction rate decreases with reaction time as the surface is not covered completely with PbO due to the lowering of the rate.
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  • Kazuo Kondo, Michiaki Matsumoto, Toyo Okubo
    1997 Volume 23 Issue 4 Pages 555-560
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    In synergistic extraction of metals, the partition mechanism between organic and aqueous phases of the synergist used plays an important role. Many studies on measurement of the partition equilibrium have been carried out so far, but few studies on the phase-transfer rate have been conducted. In this work, the phase-transfer rate of 5-chloro-8-hydroxyquinoline (HA) between toluene and aqueous sulfuric acid was measured using a stirred transfer cell. The transfer rate varied inversely as the first power of the hydrogen-ion concentration in a low pH range, and was proportional to the concentration of HA. Analysis of the experimental results taking into account the partition equilibrium at the interface between the organic and aqueous phases gives the mass transfer coefficients of HA in both the aqueous and organic films. The calculated results of the transfer rate using these values agree well with the experimental ones. The experimental results in the high pH range deviate slightly from the calculated ones. This tendency is also explained qualitatively by considering the effect of pH on the solubility of HA in sulfuric acid aqueous solution.
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  • Shuji Matsusaka, Masanori Koumura, Hiroaki Masuda
    1997 Volume 23 Issue 4 Pages 561-568
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The mechanism of particle separation was analyzed by use of the methods of particle reentrainment by airflow and centrifugal separation. Glass beads of six different sizes in a range of 21.8-100.6 μm in count median diameter were used, and the drag and centrifugal forces for particle separation were obtained experimentally. A moment balance model based on adhesive, gravitational, and separational forces was presented on an assumption of Hertzian deformation in a particle-wall contact zone. The model corresponding to each experimental method was formulated, and adhesive force was calculated from the separation force. It was found that the values of the adhesive force agreed with each other irrespective of the experimental methods, showing the analysis based on the moment balance was more reliable. Furthermore, the values of adhesive force obtained from the experiments were compared with various theoretical ones, and it was found that the adhesive force agreed approximately with van der Waals force.
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  • Atsushi Ikari, Yasuo Hatate, Ryoko Aiko
    1997 Volume 23 Issue 4 Pages 569-573
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Vapor-liquid equilibria of 1-butanol+ethanol and isoamyl alcohol+ethanol systems containing a minute amount of crotonaldehyde were measured at atmospheric pressure using an Othmer-type still. Equilibrium ratio curves of the trace component (crotonaldehyde) are shown to exhibit a characteristic shape.
    Batch rectification experiments of ethanol, 1-butanol, 1-butanol+ethanol and isoamyl alcohol+ethanol systems containing 0.1 wt% crotonaldehyde were carried out using a glass Oldershow-type column.
    The lowering of the concentration of the trace component in distillate becomes gentle with the progress of distillation. The distillation curves of the trace component are found to show a peak at the change of distillate of the major components. In the residue of batch rectification of 1-butanol and isoamyl alcohol solutions, crotonaldehyde was detected in much higher concentration than in the last distillate.
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  • Hitoshi Takami, Takehiko Kinoshita, Yoshinori Itaya, Masanobu Hasatani
    1997 Volume 23 Issue 4 Pages 574-577
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The size and velocity of atomized droplets are simultaneously measured by dual-beam light-scatter interferometry. The relationship of scattered beam intensity against a broad range of particle size parameters (101103) is theoretically analyzed, and the effect of the aperture of collimating lens is numerically studied to clarify the range to show the linear relation. It is implied that this measurement is available for particles of diameter 10200 μm when the numerical aperture of focusing lens is 5.2×10-2 in the optical system. This method is applied to the cold model of the atomized droplets. The behavior of the velocity and the droplet particle size measured by using the open optical system which has a comparatively long focus length corresponded to the conventional one.
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  • Kazuya Ijichi, Yoshimitsu Uemura, Hidekazu Yoshizawa, Yasuo Hatate, To ...
    1997 Volume 23 Issue 4 Pages 578-582
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A rotary kiln type reactor is developed to control the triboelectric charge of crosslinked polystyrene microspheres by low temperature plasma treatment. Four kinds of plasma gass (Ar, O2, CO2 and NH3) were used as plasma gases. From surface analysis and measurements of the triboelectric charge of plasma-treated microspheres, the following results are obtained.
    (1) Plasma treatment with various gases makes it possible to incorporate various functional group such as amino, carbonyl and peroxy groups on the surface of the microspheres.
    (2) Sign and triboelectric charge of the polymer microspheres are able to be charged by changing charge gas and treatment time, respectively.
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  • Gui-lin Zhang, Tamotsu Hanzawa, Noboru Sakai
    1997 Volume 23 Issue 4 Pages 583-586
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The effective thermal conductivities of porous materials are calculated with a finite element method by the fundamental equation of heat conduction in porous materials in the case of void fraction, pore shapes and thermal conductivity ratio of two phases.
    Effective thermal conductivities in the porous materials with spherical pores are larger than those with cylindrical and parallelepipedic pores, and agree closely with the Maxwell-Eucken equation. Since effective thermal conductivities in the case of cylindrical and parallelepipedic pores are almost the same, a correlative equation is obtained by using the numerical results for these pore shapes.
    To check these calculated results, the temperature distributions and effective thermal conductivities were measured experimentally under the same operating conditions as those of the theoretical analysis.
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  • Hiromitsu Miyakawa, Fumihide Shiraishi
    1997 Volume 23 Issue 4 Pages 587-590
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The effect of electrostatic field on apparent kinetic parameters in a packed-bed immobilized enzyme reactor was investigated using a mathematical model. The relationship between the dimensionless concentration of substrate consumed in the reactor and the logarithm of the unconverted fraction of substrate at the reactor outlet was nonlinear and changed remarkably according to the magnitude of electrostatic potential and the sign of charges that carry the support and substrate. For the opposite sign of these charges, the apparent Michaelis constant was less than its intrinsic value in the region of high substrate concentration, which reflects a promoting effect on the enzyme reaction by the electrostatic attraction.
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  • Tomohiro Akiyama, Jun-ichiro Yagi, Yasushi Watanabe, Shuichi Miura
    1997 Volume 23 Issue 4 Pages 591-593
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Encapsulation of a phase-change material (PCM) based on electroplating method is investigated experimentally. The encapsulated PCM has a two-layer structure, which is coated thinly by metallic nickel and rhodium. The PCM obtained has enough strength against melting-solidification cycles when the thickness of nickel is more than 50 microns. The present method offers many benefits for the practical use of PCM, such as uniform film thickness, easy and quick coating and non-sintering among capsules.
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  • Kunihisa Osasa, Tetsuya Miyazaki, Kazuhiro Sakai
    1997 Volume 23 Issue 4 Pages 594-596
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A separation test of an O/W emulsion was conducted by using a rectangular cell fitted with packed bed type sacrificial electrodes. The continuous separation process was represented by a first-order kinetic rate equation and a two tanks-in-series mixing model as previously reported (Osasa et al., 1996). Three types of electrodes were examined to increase the dissolution rate of aluminum pellets. The most efficient type of electrodes used was one in which aluminum pellets were placed on both an anode and a cathode and the polarity was switched at regular time intervals.
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  • Dan-Dong Xu, Xin-Hui Xing, Sinjiro Yamamoto, Yasunori Tanji, Hajime Un ...
    1997 Volume 23 Issue 4 Pages 597-600
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Desulfurization from pyrite by Thiobacillus ferrooxidans in a packed-bed medium -recirculatingbioreactor is examined. The concentrations of SO42- and Fe3+ elutedfrom the pyrite in the bioreactor increased with time, however, those became constant after a certain culture time. The higher concentrations of eluted products appearts inhibit is desulfurization by the bacteria. Inhibition of Fe3+ to the desulfurization process is higher than that of SO2-4. Periodical exchange production in the medium with fresh medium in the bioreactor eliminates inhibition, which results in restart of the desulfurization process.
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  • Kazuo Kondo, Kimitomo Harada, Masayoshi Shibata, Ryosuke Maeda
    1997 Volume 23 Issue 4 Pages 601-603
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    To prepare a purified chitinase from higher plants, firstly, crude enzymes were extracted from six higher plants, namely, radish seeds, sunflower seeds, watermelon seeds, bamboo leaves, orange skin, and persimmon skin. Using these crude enzymes, pH dependencies of hydrolysis reaction of colloidal chitin are investigated. For radish seeds and bamboo leaves, which have relatively high activities, the kinetics of enzymatic reaction are studied. It is clear that these reactions obey Michaelis-Menten kinetics.
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  • Toshiro Tsuji, Masakazu Hirose, Toshiharu Shibata, Osamu Uemaki, Hiron ...
    1997 Volume 23 Issue 4 Pages 604-606
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    To determine whether the particle flow from annulus to spout in a spouted bed occurs only at the bottom or in the entire bed, the particle flow rates in the annulus of a spouted bed with a flat base were measured using an optical fiber probe. As a result, it is shown that the particle flow rate from annulus to spout at the bottom of the flat base bed is larger than that of the conical base bed, and the flow in the upper region also exists and can not be ignored when the gas velocity is increased.
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  • Shin-ya Okazaki, Kojiro Abe, Masahiro Goto, Fumiyuki Nakashio
    1997 Volume 23 Issue 4 Pages 607-609
    Published: July 10, 1997
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A novel preparation method for surfactant-enzyme complexes applicable in organic media is developed utilizing a water-in-oil (W/O) emulsion. This preparation method entails simple stages while it offers the advantages of enhanced enzymatic activity in the reacting media and eliminates enzyme loss. Using the surfactant-chymotrypsin complex, peptide synthesis with amino acid derivatives was conducted in tetrahydrofuran. The surfactant-chymotrypsin complex indicates higher activity than native chymotrypsin. This modified method will facilitate the usage of enzymes in organic media as new biocatalysts.
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