KAGAKU KOGAKU RONBUNSHU
Online ISSN : 1349-9203
Print ISSN : 0386-216X
ISSN-L : 0386-216X
Volume 22 , Issue 3
Showing 1-36 articles out of 36 articles from the selected issue
  • Yuichi Fujioka, Jung Wei Shin
    1996 Volume 22 Issue 3 Pages 433-445
    Published: May 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Evaluation of the reaction rate from the carbon, hydrogen and oxygen in coal to those in gasified gas in our fluidized bed coal gasification experiments with a devolatilization reaction of coal and an oxidation reaction by oxygen was made. The experimental apparatus had a coal feed capacity of about 6 kg/h at pressures of 1.2 and 2 MPa and at temperatures of 1, 100 K to 1, 400 K.
    By arranging the experimental data for CO and H2 production rate and CH4 production rate, the simplified coal gasification reaction rate from carbon, hydrogen and oxygen in coal to those in gasified gas was acquired. Both equations of char gasification rate and methane conversion compose the simplified coal gasification reaction rate.
    The value and temperature dependency of the char gasification rate per unit carbon with devolatilization and oxidation reactions in the fluidized bed were generally the same as those of the char gasification rate without those reactions in previous studies.
    Using the acquired simplified coal gasification reaction rate for 6 coals, the calculation method of the mass balance in coal fluidized bed gasifier was presented.
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  • Yuichi Fujioka, Jung Wei Shin
    1996 Volume 22 Issue 3 Pages 446-457
    Published: May 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Experiments of pressurized fluidized bed coal gasification in our pilot at a coal feed rate from 500 to 1, 500 kg/h were conducted. Comparing the char gasification rate per unit volume of a fluidized bed and methane yield between the upper gasifier of the pilot plant and the previous bench scale apparatus at a coal feed rate of about 6 kg/h, the char combined gasification rate per unit volume in the bench scale apparatus was 3 to 4 times larger than that in the pilot plant.
    Then, the char combined gasification rate in the upper gasifier of the pilot plant calculated with a two-phase model that assumed perfect mixing of gas and solid in the emulsion phase and gas plugging flow in the bubble phase was the same as that in the previous bench scale apparatus.
    Despite the scale difference, arranging the methane production rate for the methane yield, the methane yield in the bench-scale was the same as that in the pilot plant.
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  • Yoshinori Imoto, Tadao Kasakura
    1996 Volume 22 Issue 3 Pages 458-466
    Published: May 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A fluidized bed furnace with a 0.7 m square sand bed was operated with air mass velocity of 0.19 to 0.6 kg/m2·s, compared to ordinary rates of 0.20 to 0.25 kg/m2· s. The air ratio was adjusted over a wide range of 0.62 to 1.50, compared to ordinary rates of 1.3 to 1.5. From the results of these experiments, the combustion efficiency at sand bed decreased as cake load, fuel load and air mass velocity increased. The combustion efficiency is proportional to the air ratio, therefore the combustion efficiency decreased as the air ratio decreased. A definite correlation of combustion efficiency and sand bed temperature was not obeserved in the range of 873-1, 171 K under the self combustion condition. At a high air mass velocity, the operation of the high cake load can be accomplished with a high air ratio. And at high cake load the freeboard combustion was superior to sand bed combustion.
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  • Mikio Morita, Yasuko Hirama, M. K. H. Liew
    1996 Volume 22 Issue 3 Pages 467-472
    Published: May 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A new separation and purification method for lactic acid from fermentation broth is proposed, by which poly-lactic acid produced from unpurified lactic acid is catalytically depolymerized into lactide fraction, then further purified into lactide.
    In the present study, thermal depolymerization catalysts were investigated for commercial use.
    Iron catalysts, especially metallic iron, and ferrous oxide and lactate, were found to provide almost the same catalytic activity and lactide composition in depolymerization products and those in tin octoate and antimony oxide catalysts.
    Ferrous oxide was also applied to depolymerize poly-lactic acid derived form unpurified lactic acid to compare catalytic activity and lactide composition and was confirmed to show results similar to those of pure polymer. Based on these findings, it is concluded that iron catalysts can be used commercially. Furthermore, catalytic depolymerization of poly-lactic acids with different molecular weights were studied. Polymers with Mw 5, 000-10, 000 were found to be better for production of lactide, based on the behaviour of depolymerization and lactide content in the product.
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  • Tadaaki Tanii, Masaki Minemoto, Kuniyasu Nakazawa, Yoshimasa Ando
    1996 Volume 22 Issue 3 Pages 473-479
    Published: May 10, 1996
    Released: November 12, 2009
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    An experimental study was performed to obtain some design data for a cool storage system using HCFC-141 b clathrate.
    Experiments on investigating the possibility of using the clathrate storage system as an air condition for a building were performed. The clathrate can store energy of night excess power at a cool storage density and extract it as cool heat when the energy becomes necessary in the daytime. Commercial cool storage system using CFC (Chloro Fluoro carbon) -11 (CCl3F) clathrate have already been developed. But now, the usage of CFC-11 is strongly restricted from the stand point of global enviromental protection, hence an alternative medium for CFC-11 is necessary. In this study, HCFC-141 b was selected as an alternative medium. The formation tests for HCFC-141 b clathrate were carried out in order to obtain some design data for cool storage systems. The following conclusions were obtained : (1) a cool storage system using HCFC-141 b clathrate is a more effective heat storage system than ice ; (2) addition of 0.05 wt% surfactant allowed an ideal clathrate formation/decomposition up to 40 wt% of clathrate concentration ; and (3) addition of ethyleneglycol allowed the clathrate formation/decomposition temperature to decrease, resulting in the acquisition of more cooled water.
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  • Yoshio Fuchigami, Toshiaki Inami, Yosokichi Kobayashi, Akira Hashimoto
    1996 Volume 22 Issue 3 Pages 480-487
    Published: May 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A MaxblendR (MB) impeller was adopted in the mixing reactor for a continuous polymerization reaction. When the liquid level was lower than the top of the impeller and the upper shell cover of the reactor was cooled, the monomer vaporization was accelerated to exceed the amount of the heat transfer from the jacket surface, which offered an effective means to remove the heat of reaction. The rate of monomer vaporization (v) by a MaxblendR impeller changed as a function of the 1.4 th power of the impeller speed, the 0.4 th power of the impeller diameter and the 0.45 th power of the nitrogen flux.
    The value of the overall coefficient of heat transfer (Uj) and v were estimated as 304 kJ/m2h°C and 26.7 kg/m2h, respectively for the commercial scale reactor under conditions of Pv = 1. 5 kw/m3 (73 rpm) from the experimental value of Uj = 460 kJ /m2 h°C and v=67 kg/m2h determined from the heat balance of the pilot scale reactor. Based on those values, a commercial reactor with a productivity of 750 kg/h was designed assuming the difference between the jacket temperature and the reaction temperature (Δtj) =-12.8°C. Parameters were found to be Uj =326 kJ/m2h°C, v=31 kg/h (at the purge gas rate of 1/7 that of the pilot scale) and Δtj =-12.5 for the commercial reactor, suggesting that the ability of heat transfer of the commercial reactor was designed conciderably larger than the estimated value.
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  • Shoichi Takao
    1996 Volume 22 Issue 3 Pages 488-495
    Published: May 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The rheological properties of a highly loaed coal water mixture (CWM) were investigated according to the CWM Quality TEST Method (CCUJ United Method). The representative apparent viscosity and viscosity power index were both increased with weathering of the feed coal. It was considered that acidification and an increase in hydrophilic functional groups on the coal surface were the main causes of the changes. The representative apparent viscosity increased and viscosity power index decreased with the increase in ash contents of feed coal. It was considered that clay minerals liberated from the coal surface caused the changes. Agitation was found to be very effective to decrease the representative apparent viscosity of a CWM and to improve rheological properties. The rheological properties greatly changed with coal concentratin and temperature of the CWM, while they changed only slightly with the amount of dispersant added and with weight percent of particles over 75 μm in size.
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  • Toyozo HAMADA, Sachiko MATSUOKA, Shuji NAKATSUKA
    1996 Volume 22 Issue 3 Pages 496-502
    Published: May 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A dehydration process of ethanol solution usingpolyion complex (PIC) membrane by pervaporation was designed. A permeation equation with experimentally detere mined permeability was used to describe the permeate flux and separation factor under various operating conditions. Considering material and heat balances in a module using the equation, the effects of permeate side pressure and recycle operation on dehydratiion performance were evaluated. When 94 wt% ethanol solution was dehydrated up to 97 wt%, no significant effect on membrane area was observed under permeate side pressures of 13-666 Pa. When ethanol concentration in the feed solution was below 94 wt%, high permeate flux was obtained by a recycle operation. From the result of these examinations, dehydration of ethanol solution on a pilot-scale was performed. It was verified that the permeation equation could be applied for design of a dehydration process for ethanol solution. A dehydrated ethanol product could be stably obtained from 94 wt% ethanol solution using a PIC membrane over a long period.
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  • Mitsuhiro Ito, Ken-ichi Nagano, Kimihiko Hino
    1996 Volume 22 Issue 3 Pages 503-511
    Published: May 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The effect of ball size, ball charge ratio, filling ratio of powder in ball charge in a tumbling ball mill and mill diameter on parameters of comminution kinetics equation and on a revice coefficient for a parameter were experimentally investigated. Tested powders were cement raw mix and cement clinker. In addition, a simulation of closed-circuit grinding was carried out as functions of the parameters. Using these results, ways to increase production capacity of closed-circuit grinding were investigated. The lower the filling ratio of powder in the ball charge under the condition of constant passing rate of powder through a mill, the more the production capacity increases both the raw mix and the clinker grinding. Balls of diameter of about 30 mm increase the capacity further in the grinding of the raw mix. On the other hand, a smaller size of balls still increases the capacity in grinding of the clinker under the condition that the fineness is controlled by 31 μm sieving. Ball size, however, does not affect the capacity under the condition controlled by specific surface area.
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  • Tatsuro Matsui, Hiroshi Morimoto
    1996 Volume 22 Issue 3 Pages 512-519
    Published: May 10, 1996
    Released: November 12, 2009
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    Phenylacetylene (PA) damages the quality of styrene. There are small amounts of PA in styrene which comes from extraction of C 8 distillate in or ethylene plant and from dehydration of ethylbenzene. There is about 34 mol/m3 of PA in C 8 distillate in the former process and we have to reduce the concentration of PA lower than 0.10 mol/m3 by hydrogenation over a Pd catalyst. But severe hydrogenation would convert styrene to ethylbenzene. We proposed a kinetic model for the gas and liquid upflow fixed bed differential reactor. The mass transfer coefficent of PA between the solid-liquid interface, which was observed in the experiments of the differential reactor, agreed well with the theoretical one. According to this model, larger Kφ favored higher ST selectivity. Experimental results of an integral reactor were in good accordance with the proposed model., if we introduced a backmixing model.
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  • Yasuhiro Imamura, Satoji Kobayashi, Hikoji Inazumi
    1996 Volume 22 Issue 3 Pages 520-526
    Published: May 10, 1996
    Released: November 12, 2009
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    The gas entrainment characteristics of an ejector fitted with a straight-type throat was investigated experimentally using a horizontal flow liquid jet.
    The gas entrainment rate of the horizontal flow liquid jet increased with increase in liquid flow rate and throat diameter. The entrainment rate was shown as a function of power input per unit volume of liquid and throat diameter. The empirical correlation obtained in this work can be predicted by the observed values of the entrainment rate within an error of ±20%.
    The relationship between the driving pressure and the operating conditions was investigated in the case of single nozzles. As a result, an empirical correlation by which the observed values of the motive pressure can be predicted within an error of ±5% was obtained.
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  • Yasuo Hirose, Hiroshi Tachibana, Hirotaka Soh
    1996 Volume 22 Issue 3 Pages 527-533
    Published: May 10, 1996
    Released: November 12, 2009
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    Some isotopes are separated and concentrated by distillation. The characteristics of isotope distillation due to extremely low relative volatilities compared with ordinary distillation columns are as follows : 1) a large number of theoretical plates ; 2) high reflux ratio ; and 3) constant vapor and liquid flows due to the same chemical and physical properties except vapor pressure which require no enthalpy balances on each plate. Two distillation calculation algorithms I and II based on the Newton-Raphson method are proposed : algorithm I whose submatrix dimensions are 2 m, in which the vapor-liquid equilibrium ratio is a function of only liquid compositions and algorithm II whose submatrix dimensions are 2 m+ 1, in which the equilibrium ratio of vapor and liquid equilibrium relationships is a functions of only temperature, where m is the number of components. Numerical examples are shown for the above two algorithms : As the first example, a distillation process of nitric oxide is proposed to concentrate 14N17O. As the second example, a distillation column with an intermediate reboiler in the methane process to concentrate 13CH4 is studied. In spite of the large number of plates and high reflux ratio, the two examples are successfully simulated.
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  • Kazuo Kondo, Kunio Shinohara, Keisuke Fukui
    1996 Volume 22 Issue 3 Pages 534-541
    Published: May 10, 1996
    Released: November 12, 2009
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    The number of pads which interconnect microprocessor to both RAM and secondary cash increases rapidly for the microprocessor after 64 bits. This increase requires a material revolution for high density interconnection such as bumps which are microconnectors.
    The bumps show sharp humps at the upper flow side for the Reynolds numbers of 40.57 and 81.14. The lower flow side also has humps and their height decreases with the increase of Reynolds number. The hump becomes flat at the upper flow side for a Reynolds numbers of 405.7 and the lower flow side no lorge shows the hump.
    In this report, the bump formation mechanism is discussed with microscopic flow and mass transfer which were calculated by numerical flow computation. The bump shapes, mentioned above are caused by following two microscopic flow patterns. One is the separated vortices both at the upper and lower flow side cathode corners, and the other is penetration flow which starts from the upstream bulk solution to the cathode center and to the lower side bulk solution. The two-dimensional calculated flux profiles coincide well with the above mentioned observed bump shapes.
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  • Kazunori Tsurumi, Katsutoshi Inoue
    1996 Volume 22 Issue 3 Pages 542-550
    Published: May 10, 1996
    Released: November 12, 2009
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    Adsorption behavior of platinum (II) ammine complex ions onto silica gel was investigated at 30°C in basic ammoniacal solution with varying concentrations of ammonium chloride. Two reactions were sugested for the platinum adsorption as follows :
    GNH4+Pt (NH3) 4+++Cl-_??_GPt(NH3)4Cl+NH4+ K1
    GNH4+GH+Pt (NH3) 4+++NH3_??_G2Pt (NH3) 4+2NH4+ K2
    where GH denotes silanol groups on silica gel.
    The composite process of these reactions gives the following equation, and it agreed with experimental data.
    [GPt] / [Pt++] =K1 [GNH4] [Cl-] / [NH4+] +K2' [NH4] 2/ [NH4+] 2
    The bidentate adsorption of platinum ammine complex ion onto silica gel retains a site of ammonia and an adjacent site of free silanol group. In the reduction process of platinum ammine complex ions adsorbed on silica gel into platinum metal, calcination in the air at 350 °C prior to reduction in H2 causes an exothermic reaction due to the combustion of ammonia adsorbed. The exothermic reactin induces sintering of platinum particles. The direct reduction in H2 at 350 °C led to highly dispersed platinum on silica gel.
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  • Toshiyuki Nonaka, Mutsumi Suzuki
    1996 Volume 22 Issue 3 Pages 551-559
    Published: May 10, 1996
    Released: November 12, 2009
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    A method of feature extraction and smoothing of a noisy contour of a particle is developed using a Bayesian model. The time series representing boundary points of a contour is able to be decomposed into trend, periodical, autoregressive and observation error components by the fixed-interval smoother algorithm with the Kalman filter. The performance of this smoothing algorithm is illusrated with some examples.
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  • Kimihito Narukawa, Hidenori Goto, Yong Chen, Ryouhei Yamazaki, Shigeka ...
    1996 Volume 22 Issue 3 Pages 560-565
    Published: May 10, 1996
    Released: November 12, 2009
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    To develop a highly efficient CFB generating process, basic RDF combustion properties are observed by the thermal balance technique for two RDF produced by different processes. It was observed that RDF weight was reduced in two stages with exothermic reaction in their combustion. This result indicates that these RDF consist of two kinds of combustibles, one burning at low temperature and another at high temperature. From the small weight difference of RDF sample between after combustion and after pyrolysis, it was found that combustion is controlled mainly by gas-phase combustion of volatile matter released by pyrolysis. Furthermore, it was also found that the first stage reaction of each RDF has the same reaction mechanism, however the reaction mechanism of the second stage depends on the RDF production process.
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  • Etsuro Naito, Yasutaka Nagano
    1996 Volume 22 Issue 3 Pages 566-574
    Published: May 10, 1996
    Released: November 12, 2009
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    A numerical investigation has been conducted to study the effects of free convection on forced convection heat transfer in the thermal entrance region between vertical parallel plates with upward flow of low Prandtl-number fluids. Numerical solutions are given for two thermal conditions of parallel plates : one wall heated with the other wall insulated ; and both walls heated in the same uniform states. The results are discussed in conjunction with those of uniform irrotatinal velocity. Numerically predicted friction factors and local Nusselt numbers are compared with their counterparts for pure forced convection. For use in practical applications, correlation equations are developed for the friction factors and the local Nusselt numbers.
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  • Mitsuru Sese, Keisuke Hashimoto, Hideto Yoshida, Sukeharu Kawamura
    1996 Volume 22 Issue 3 Pages 575-581
    Published: May 10, 1996
    Released: November 12, 2009
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    Numerical simulation and experimental studies have been conducted on the effect of particle size distribution on the surface roughness and porosity for thin particle layers. When particles with wide size distribution are deposited on the test surface, surface roughness of the particle layer increases. The degree of surface roughness also increases when the particles are agglomerated. Numerical simulation indicates that the porosity becomes lower when non-agglomerated particles with narrow particle size distribution are used.
    On the other hand, the porosity becomes lower when agglomerated particles with wide particle size distribution are used.
    From the experimental results, porosity of the particle layer decreases when particles with wide size distribution are used. This is because of the particle agglomeration.
    It is also found from numerical simulation that the number of closed void spaces in the particle layer increases when agglomerated particles with wide size distribution are used.
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  • Mutsuhito Ito, Fujio Watanabe, Masanobu Hasatani
    1996 Volume 22 Issue 3 Pages 582-589
    Published: May 10, 1996
    Released: November 12, 2009
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    The transient behaviour of an adsorption heat pump (AHP) with a multiple adsorbent-tube (MAT) type adsorber containing a silica gel module (ST-module), which was proposed to enhance heat transfer, has been simulated numerically in a cycle operation. Numerical results of heat and mass transfer accompanying the adsorption/desorption process of water vapour in the ST-module agreed with experimental ones. In addition, the time-changes of the amount adsorbed, temperature distributions in the MAT type adsorber, and periods of adsorption/desorption can be compositely explained by the isotherm and the adsorption/desorption rates. Also, form parametric studies on the performance of this AHP, it was found that the residual amount adsorbed at the end of the desorption process prevents effective generation of heat in the cycle operation of this AHP.
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  • Masaru Hakoda, Atsushi Enomoto, Kozo Nakamura
    1996 Volume 22 Issue 3 Pages 590-596
    Published: May 10, 1996
    Released: November 12, 2009
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    Electro-microfiltration bioreactor (EMFBR) was applied to the high density culture of Streptococcus lactis 527, and the effect of electric field on the filtrate flux and the cell concentration was examined experimentally.
    The EMFBR allowed complete retention of cells in the fermentor and continuous removal of inhibitory metabolizes. S. lactis was grown in the EMFBR with the maximum concentration of 24.2 g-dry cells/ l, about 10 times as much as that of the conventional batch culture, and this improvement was due to removal of lactic acid from the fermentor. The yield of cell against glucose YX/S and the maintenance coefficient m both increased by application of an electric field. The experimental results showed that EMFBR could be effective if the experimental conditions were chosen properly.
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  • Toshiyuki Teshiba, Masaharu Takao, Satoru Komori, Yasuhiro Murakami, H ...
    1996 Volume 22 Issue 3 Pages 597-602
    Published: May 10, 1996
    Released: November 12, 2009
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    A measuring technique to visualize the motion of media particles has been developed for a horizontal type sand mill, in which internal blade and external cylinder rotate inversely and independently. Using this experimental technique, velocity distribution, intensity of velocity fluctuations and appearance frequency of grinding media in the mill can be measured. Relating to these flow characteristics of media particles for both rotation methods, the grinding performance of calcium carbonate with alumina beads is discussed. As a result, it is found that the median diameter of ground products obtained in both rotation methods can not be correlated only with the intensity of velocity fluctuations having been used to date, but can be correlated well with the intensity of velocity fluctuations weighted by appearance frequency.
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  • Yutaka Ohkubo, Yoshiki Takahashi
    1996 Volume 22 Issue 3 Pages 603-609
    Published: May 10, 1996
    Released: November 12, 2009
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    The lifting criteria of an induction-charged spherical particle in a field with horizontally set parallel plate electrodes is investigated by an experimental approach, using alumina, silica, and polyurethane powders.
    The present paper gives 0.25 kV/mm as the minimum lifting intensity of the electric field. The experiment proves that electrical conductivity of a particle is an important factor in governing lifting criteria so that powders with high conductivity, over 10-8 (Ωm) -1 could easily be lifted up. Polyurethane powders with below 1% water fraction on the surface of the particles cannot be lifted up even under a high electric field intensity, because of their low conductivity. By adding water to the powders, the conductivity increases so that the particles are lifted up in over 3% water fraction. But at over 10% water fraction, the binding force of the water bridge between particles governs the total force balance.
    With considerations of the electrostatic upward force of the particle and the capillary binding force of the water bridge between particles and the gravity force as downward forces, estimations of lifting criteria by a theoretical approach are identical with the experimental results.
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  • Yasunari Matsuno, Atsushi Tsutsumi, Kunio Yoshida
    1996 Volume 22 Issue 3 Pages 610-614
    Published: May 10, 1996
    Released: November 12, 2009
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    Three-phase coal water mixture (CWM) in which small gas bubbles were dispersed with surfactants was developed to reduce the apparent viscosity of highly loaded CWM. The gas holdup in the three-phase CWM was 0.3-0.4. The rheological behavior of the three-phase CWM has been studied in a coaxial rotating cylinder rheometer at 275-323 K. The rheological behavior becomes increasingly pseudoplastic, and the apparent viscosity decreases with the increase in the gas holdup. Little temperature dependency of flow curves for the three-phase CWM was observed. Significant reductions in apparent viscosity were achieved for the three-phase CWM. The apparent viscosity of the three-phase CWM was one fifth as large as that of CWM at 275 K and one third at 288 K. It was found that three-phase CWM makes it possible to transport highly loaded coal slurry with reduced viscosity even at low temperature.
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  • Toshifumi Ishikura, Hiroshi Nagashima, Mitsuharu Ide
    1996 Volume 22 Issue 3 Pages 615-621
    Published: May 10, 1996
    Released: November 12, 2009
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    The flow rate of the gas in the annular section, the particle circulation rate, the pressure drop and the particle hold-up in the tube section were measured for a spouted bed fitted with a porous draft tube. The results were more or less different from the data of a spouted bed fitted with a conventional (solid) draft tube.
    The experimental relationships between the items as described above and the design factors of distance of entrainment zone and its diameter, and operating factors such as the gas velocity and the particle diameter were determined. A correlation concerning the particle circulation rate was presented in the operating region where the particle circulation rate increased in proportion to the gas velocity.
    In addition, three patterns of particle flow in both porous and solid draft tubes were recognized by determining the pressure drops and the particle hold-up in the tube. These three patterns could be described as follows : a stable spouting region in which the particle hold-up was insensitive to the gas velocity ; a pulsing spouting region in which the particle hold-up varied with the gas velocity ; and a clogging region within the tube.
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  • Jun Yosida, Kuniaki Gotoh, Hiroaki Masuda
    1996 Volume 22 Issue 3 Pages 622-628
    Published: May 10, 1996
    Released: November 12, 2009
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    'Size segregation' is a typical phenomenon usually accompanied with flow of particles. It has been demonstrated experimentally and macroscopically. However, the microscopic mechanism is difficult to observe, and it is not understood sufficiently. In this study, the experiment focused on size segregation simulated using the distinct element method. A 2-dimensional simulation for the full model of the experiment indicates equivalent behavior. However, size segregation in an accumulated layer is not properly shown. Next, the simple partial model is simulated using 2-and 3-dimensional analysis. The 2-D result does not show the size segregation clearly due to the wide scattering of data, but that of 3-D shows that it is possible to simulate the segregation properly. Also, detailed observation of the movement of each particle demonstrates the validity of the mechanism of size segregation which was presented from the experiment.
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  • Mikio Kawagoe, Takashi Maeoka
    1996 Volume 22 Issue 3 Pages 629-634
    Published: May 10, 1996
    Released: November 12, 2009
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    We constructed a new type of external-loop airlift column with a reverse conical riser, and investigated flow characteristics of the column experimentally. Since this type of column is able to keep solid suspension in the riser, it will give favorable conditions for the culture system in which mycelium pellets are formed.
    Radial and axial distributions of gas holdup in the tapered section were measured using an electroresistivity probe method. Liquid circulation velocity was obtained by a tracer method. As a result, the radial gas holdup distribution was found to agree with a well-known second order distribution, except for the region of low gas velocity. The axial distribution of gas holdup was found to be expressed by a simple expression derived from Zuber-Findlay's equation. The gas holdup in the conical section alone coincided with the correlation of gas holdup for the standard bubble column, using an appropriate mean superficial gas velocity. The liquid circulation velocity was correlated by a semitheoretical equation derived from the pressure balance along the circulation loop.
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  • Naotake Katoh, Toshiaki Oda
    1996 Volume 22 Issue 3 Pages 635-640
    Published: May 10, 1996
    Released: November 12, 2009
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    Frequency response calculation was carried out for a continuous cooling crystallizer where cooling temperature and crystal production rate are regarded as input and output, respectively. It was found that appropriate selection of amplitude and augular frequency almost stabilized sustained oscillation of the crystal production rate. To explain this phenomenon, the theory of signal stabilization was introduced. Based on this theory, it was interpeted that sustained oscillation was due to a strong nonlinearity of nucleation rate and that these nonlinear characterestics enabled us to reduce sustained oscillation by cooling temperature input with suitable amplitude and angular frequency. From this fact, it was recognized that the theory of signal stabilization was useful to the control system design of continuous crystallizer which showed sustained oscillation.
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  • Masatoshi Yoshida, Takehiro Gono, Naohiro Mikamoto, Shigeru Matsumoto
    1996 Volume 22 Issue 3 Pages 641-647
    Published: May 10, 1996
    Released: November 12, 2009
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    A new type of zone melting process was developed, in which an axial temperature distribution alone was moved while both heaters and a sample container were fixed. The controller for moving temperature distribution was designed based on the method previously proposed by authors for distributed parameter systems. The controller performance was satisfactor for various operation conditions. Experimental results with an eutectic organic compound show that the separation efficiency of the present process bears comparison with that of the conventional process and depends on the temperature gradient at the crystallizing interface, as well as the length of melting zone.
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  • Eiji Iritani, Hideo Nagaoka, Toshiro Murase
    1996 Volume 22 Issue 3 Pages 648-654
    Published: May 10, 1996
    Released: November 12, 2009
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    Variations of the filtration rate with time and the properties of the filter cake were examined for microfiltration of binary mixtures of fine particles. Both the average porosity and the average specific filtration resistance were determined from filtration experiments in which a filter was subjected to a sudden reduction in its filtration area. The average porosity in the filter cake of the binary mixtures of fine particles was explained well by the mixture packing model in which small particles fill the voids between large particles. The decrease in the ratio r of small to large particle size caused a significant increase in the value of β, which is a measure of the mixing action between large and small particles. In addition, the average specific filtration resistance of the binary mixtures was obtained on the basis of the additive law of the effective specific surface area. The filtration rate in the binary mixtures was evaluated accurately by using both the average porosity and the average specific filtration resistance.
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  • Tomoyuki Uchiyama, Masaru Otani, Yukiaki Otomura, Kunio Shinohara
    1996 Volume 22 Issue 3 Pages 655-661
    Published: May 10, 1996
    Released: November 12, 2009
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    The effect of the coated composite surface of particles on the mechanical properties of the powder bed was investigated. Polyethylene-silica surface composite powder was prepared at several coating ratios with Hybridizer. Various tests on mechanical properties of the powder bed were carried out with the prepared powder, and the following results were obtained : The ultimate tensile strength depends only on the conhesive force between particles, and the contact probability model of composite particles led to good agreement between the experimental and calculated values.
    The coefficient of internal friction and cohesive shear strength were influenced due to the interlocking effect of the surface roughness of composite particles. The effects of coating particles became small with dynamic properties like angle of repose. It is possible to control the mechanical properties in a stepwise fashion by changing the coating ratio of the particles.
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  • Osamu Miyatake, Hiroki Morita, Kenjiro Shibata
    1996 Volume 22 Issue 3 Pages 662-668
    Published: May 10, 1996
    Released: November 12, 2009
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    To offer the essential basic information for analyzing the thermal-energy storage system based on the form-stable phase change of plastics, particle-to-fluid heat transfer coefficients in fixed beds packed with cross-linked cylindrical plastic particles subjected to melt-freeze cycles were evaluated experimentally using the extended Schumann's theory, and a formula for estimating the heat transfer coefficient was presented.
    The resulting heat transfer coefficients were found to be definitely lower than those predicted from previously published work, due to the melt adhesion between adjacent plastic particles, which increases their contacting surface area and, consequently, increases the dead space in the interstitial flow region.
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  • Nobuhiko Fukushima, Yasuo Kousaka, Yoshiyuki Endo, Isao Yamakawa
    1996 Volume 22 Issue 3 Pages 669-675
    Published: May 10, 1996
    Released: November 12, 2009
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    To detect the nonvolatile solute (Residue After Evaporation : RAE) concentrations in variousliquids (i. e., 30% hydrogenperoxide, 9.4% ammonia solution, Isopropyl alcohol and methanol), a method consisting of liquid atomization, evaporation, diffusional deposition and condensation nucleus counting was applied and examined. From the measurements of size distribution of droplets atomized in air and deposition rate as a function of particle diameter in the flow system, the relationships (correlation curves) between the number concentration of residue particles after diffusional deposition and solute concentration were obtained. These correlation curves were used to accurately measure the RAE levels of several commercially available liquids of different grade. The measured impurity (RAE) concentrations were found to be ober ppm order, and were much higher than those of ultrapure water.
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  • Hiromasa Komatsu, Hironobu Yamamoto
    1996 Volume 22 Issue 3 Pages 676-682
    Published: May 10, 1996
    Released: November 12, 2009
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    Vapor-liquid equilibrium data for three ternary systems of acetone-ethanol-N, N-dimethyl formamide (DMF), ethyl acetate-water-DMF and acetone-chloroform-ethyl acetate, and for four binary systems of DMF-ethanol, acetone, water and ethyl acetate have been observed at atmospheric pressure. Wilson parameters of these systems were determined. Satisfactory values for vapor-liquid equilibrium of ternary system may then be obtained by use of the Wilson parameters obtained from binary system data.
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  • Yoshiaki Ogo, Junji Miyazaki, Masazo Ogawa
    1996 Volume 22 Issue 3 Pages 683-686
    Published: May 10, 1996
    Released: November 12, 2009
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    The effects of guar gum and xanthan gum as stabilizing additives on the sedimentation stability, plastic viscosity and yield value were compared to prepare slurrres with different coal particle size distributions. The coal particle size distribution was essential factor for the preparation of CWS and both gums were effectively used in broad particle size distribution slurries as stabilizing agents.
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  • Noboru Kamei, Setsuro Hiraoka, Yoshihito Kato, Yutaka Tada, Hyeong-Gyu ...
    1996 Volume 22 Issue 3 Pages 687-690
    Published: May 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The effect of liquid height on power consumption in a non-baffled agitated vessel was clarified experientally. On the other hand, the power correlation proposed in our previous paper was modified by changing the similarity parameter γnp0.7 (b/D) to the modified one γnp0.7 (b/H) which contained the liquid height H. The resultant power correlation was well correlated not only with the present experimental result but also with the expreimental result by Nagata.
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  • Ken-ichiro Suehara, Shinsuke Goto, Nobuyuki Uozumi, Takeshi Kobayashi
    1996 Volume 22 Issue 3 Pages 691-694
    Published: May 10, 1996
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Callus could be induced from the leaf and root of the celery regenerated plant. The somatic embryogenesis frequency of the callus induced from the leaf of the regenerated plant was about three-fold as high as that of callus induced from the F 1 celery plant. On the other hand, callus induced from the root of the regenerated plant showed a low embryo formation frequency. There was no significant difference in the morphology between the regenerated plant using the callus induced from the F 1 celery plant and the regenerated plant using the callus induced from the leaf of the regenerated plant.
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