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Hiromi Takeuchi, Kyoji Sato, Masahiko Mitsuda, Toshio Kurosaka, Eiichi ...
1990 Volume 16 Issue 5 Pages
859-866
Published: September 10, 1990
Released on J-STAGE: November 12, 2009
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For heat collection from air in cold districts, an important problem is how to prevent and/or remove the frost layer deposited on the cooling surface of the evaporator, because the frost layer will increase the thermal resistance and the coil will become blocked. Frost removal tests were made in a bubbling fluidized bed using three kinds of fluidized particles to see their frost removal capability. It was found that fluidized silica sand had some frost removal capability but was not sufficient to remove the frost layer completely.
To cope with this problem a solid-circulating heat collector was developed. The apparatus consisted of a riser and a moving bed, with solid particles circulating between them as heating medium. Cooling surfaces for the evaporator were inserted into the moving bed. There is little possibility of frost layer formation on the cooling surface since only a small amount of air and moisture exist in the moving bed. Furthermore, the pressure drop in this heat collector is much lower than that in the bubbling fluidized bed since there is no need to have a distributor in the bottom section of the riser. Based on experimental results with the small apparatus, a bench-scale plant combined with a 10 kW heat pump system was developed. Test runs were conducted under outdoor conditions during the winter season in Sapporo. From a six-day continuous test run it was confirmed that the system operated stably without frost formation.
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Motokazu Kikuchi, Haruo Endo, Koji Inagaki, Mikio Kanzaki, Shigeru Mat ...
1990 Volume 16 Issue 5 Pages
867-874
Published: September 10, 1990
Released on J-STAGE: November 12, 2009
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To clarify the mechanism of cycling in continuous whipping of cream, variations of several state variables were measured during the cycling and the effects of various operating variables on the whipping characteristics were examined. The results show that the gas holdup in the dasher is a controlling factor in the whipping process, and suggest that the interaction between the pressure in the dasher and the pressure drop in the outlet piping causes the cycling. This knowledge was utilized to develop a new continuous whipping machine in which the cycling phenomenon was removed in a wide operation range by the introduction of a control loop of dasher pressure.
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Yasuyuki Watanabe
1990 Volume 16 Issue 5 Pages
875-881
Published: September 10, 1990
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A melt of NaCH
3COO · 3H
2O as a heat storage material was supercooled without nucleation even under its melting point (331K) during continuous cooling at 1K/min. The degree of its supercooling depended strongly on the heating temperature being before the continuous cooling and increased with the rise of heating temperature. When the heating temperature reached 339K, the supercooling became to be about 80K as a median value and remained almost constant with heating above that temperature. On the other hand, in the case of NaCH
3COO· 3H
2O melt added Na
3PO
4·12H
2O as a nucleation agent, the degree of its supercooling was an amazingly smaller value (5K) than that of the case without nucleation agent. Furthermore, the peculiar fact that the supercooling was suddenly increased by heating beyond 363K was discovered. Additionally, such nucleation behavior was found to appear only after that the melt with Na
3PO
4·12H
2O was solidified by cooling. From these nucleation characteristics, the acceleration mechanism for nucleation of the melt was examined qualitatively.
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BohYoh Shibata, Yoshifumi Tsuge, Hisayoshi Matsuyama
1990 Volume 16 Issue 5 Pages
882-890
Published: September 10, 1990
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A consultant system which aids operators during a chemical plant emergency is proposed. The structure of its database is so designed as to allow the acquisition of the necessary data to complete the database by use of the family of greatest sets of candidates defined for the fault diagnosis subsystem used in it. The consultant system and the tool which aids one in constructing its database are made for an oxidation subprocess of an acetic acid process in order to demonstrate the usefulness of this system by simulation.
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Yoshinori Kutsuwa, Masahiro Ohga, Hisayoshi Matsuyama, Atsuo Kodama, M ...
1990 Volume 16 Issue 5 Pages
891-898
Published: September 10, 1990
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Chemical plants require tank facilities to store the products made in the processing units. The operation of the storage tanks is very complicated since it is closely related to both production planning and delivery planning. In this paper the operation scheduling of storage tanks is investigated to minimize the number of tank changings under satisfying the demands for products. The scheduling problem is formulated as a mixed integer programming (MIP) problem to determine the assignment of tasks and the times of tank changing. An algorithm for solving the MIP problem is developed by use of linear programming and the branch-and-bound method. As an illustration, feasible schedules for tank systems are effectively made so as to reduce the frequency of tank changing.
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Fumihiko Gujima, Bohyoh Shibata, Yoshifumi Tsuge, Junichi Shiozaki, Hi ...
1990 Volume 16 Issue 5 Pages
899-906
Published: September 10, 1990
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The algorithm for fault diagnosis by use of the signed directed graph has been improved so as to obtain diagnostic results of satisfactory accuracy. The improved algorithm requires both information about delays among state variables in a chemical process that are related to the manner of propagation of a failure, and infomation about dynamic characteristics of measured variables to be practically observed in the process. The usefulness of this algorithm is demonstrated by its application to a pilot plant.
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Tomoshige Nitta, Toshiya Tada, Yoshiki Yakushijin, Takashi Katayama
1990 Volume 16 Issue 5 Pages
907-914
Published: September 10, 1990
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Experiments were performed on the height equivalent to a theoretical plate (HETP) of chiral columns with cellulose tris (phenylcarbamate) both in liquid chromatography (LC ; with hexane eluent) and in supercritical fluid chromatography (SFC; with carbon dioxide eluent). The overall mass transfer resistance for polymer-coated silica gel particles is smaller than that for the uncoated silica gel in a low-velocity region ; however, in a high-velocity region where intraparticle diffusion is a ratecontrolling step the polymer-coated silica gel shows higher resistance than the uncoated gel. There may be two plausible explanations : 1) an increase in the tortuosity factor of the porous particles due to the inclusion of polymers, or 2) particle coagulation due to the polymers coated on the outside of particles. It is shown that the HETP for SFC is correlated well with the same equation as that for LC when the fluid density and the diffusion coefficient of a solute are practically estimated.
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Kaoru Onoe, Takashi Fujii, Toru Tayama, Tadashi Shirotsuka
1990 Volume 16 Issue 5 Pages
915-923
Published: September 10, 1990
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The molecular-weight distribution of liquid products from short-contact time liquefaction of Taiheiyo coal residue was meaured by gel-permeation chromatography, and the function representing the molecular-weight distribution from coal particle to liquid products was estimated. A model of continuous lowering of the molecular weight was proposed by assuming two types of reactions : coal particle to liquid products and subsequent lowering from high to low molecular weight of liquid products. It was demonstrated that : 1) The time course of molecular-weight distribution during liquefaction can be estimated from the reaction rate of coal particle, the distribution function, and the rate of lowering of the molecular weight of liquid products. 2) In the early stage of liquefaction, the profile of molecular-weight distribution was much influenced by both the coal conversion and the distribution function. 3) The effect of reaction rate of coal particle on liquid products can be estimated by considering the accumulation within a certain specified range of molecular weights.
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Kazuya Ijichi, Yasuhiko Tanaka, Yoshimitsu Uemura, Yasuo Hatate, Kunio ...
1990 Volume 16 Issue 5 Pages
924-930
Published: September 10, 1990
Released on J-STAGE: November 12, 2009
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Characteristics of a spouted bed with draft tube were measured in terms of solids holdup in the draft tube, solids circulation rate and gas flow rate in the annular section. Using iron powders as the bed material, an induction transducer method was developed to obtain the solids holdup.
It was found that there are two kinds of solids flow regimes along with the change of gas velocity in the draft tube. One is the dilute-phase flow regime, where the solids holdup is almost insensitive to the gas velocity and no descending flow of solids exists, and the other is the densephase flow regime, where the solids holdup is affected by the gas velocity and the particles are flowing downward.
In addition, the solids holdup in the draft tube, solids circulation rate and gas flow rate in the annular section were experimentally measured by changing gas throughput and bed weight as operating parameters, and also by changing tube separation distance and draft tube diameter as design parameters.
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CO2+ PVAc and CO2 +PBMA systems
Ning-He Wang, Shigeki Takishima, Hirokatsu Masuoka
1990 Volume 16 Issue 5 Pages
931-938
Published: September 10, 1990
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The solubilities of carbon dioxide in poly (vinyl acetate) and poly (butyl methacrylate) were measured by the piezoelectric-quartz sorption method at fixed temperatures of 313.2K, 333.2K and 353.2K, and pressures up to 10MPa. Pressure dependence of the crystal frequency was investigated experimentally, and no reference crystal was used in this work. This is a feature of our method that differs from other work. Furthermore, the solubility data were correlated by Sanchez and Lacombe's EOS and Kumar's EOS. It was found that Kumar's EOS is satisfactorily applicable to these systems.
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Meguru Kaminoyama, Kojiro Akabane, Kazuyoshi Arai, Fumio Saito, Mitsuo ...
1990 Volume 16 Issue 5 Pages
939-945
Published: September 10, 1990
Released on J-STAGE: November 12, 2009
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Three-dimensional flow of Bingham fluid in an anchor impeller mixer was numerically analysed. The basic equations were composed of the equation of continuity, the equation of motion and the model equation representing rheological characteristics of Bingham fluid. The analysis was performed by the FDM method. An empirical technique was investigated to obtain the analysis with stable solution using a vessel with coaxial cylinder, in which the flow behaviour can be analytically calculated. This technique was applied to the anchor impeller mixer. Consequently, the characteristic velocity distribution of the fluid could be quantitatively determined. The apparent viscosity of the liquid was also found to have lower values in the vicinity of the impeller and to increase rapidly with increasing distance from the impeller. The reliability of this method was confirmed by the good agreement between the numerical results and the experimental data obtained for the free surface of the slurry in the mixer.
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Kazuyoshi Arai, Kojiro Akabane, Meguru Kaminoyama, Fumio Saito, Mitsuo ...
1990 Volume 16 Issue 5 Pages
946-952
Published: September 10, 1990
Released on J-STAGE: November 12, 2009
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This paper presents a method using an electrode probe system to determine the boundary between stagnant and flow regions of a slurry which has the characteristics of a Bingham fluid, in a stirred vessel. The probe consists of a fine tube playing the roles of an anode and a tracer injector, and eight fine needles serving as cathodes. The distance between an anode and each cathode is kept constant at 8 mm. The tracer including electrolyte was injected from the fine tube at constant feed rate into the fluid. The output potentials from each cathode were measured with a signal-processing circuit. As a demonstration, a slurry with high solid concentration of 50 wt.% fine CaCO
3 powder in tap water was used as the Bingham fluid. It was found that the boundary of the fluid flow in the Rushton turbine and 6-blade paddle impellers mixer can be measured by the proposed method. The experimental results were confirmed by another visualization method using an Indian ink.
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Osamu Miyatake, Akihiro Yamada, Yuji Tsutsui, Itsuo Tanaka
1990 Volume 16 Issue 5 Pages
953-959
Published: September 10, 1990
Released on J-STAGE: November 12, 2009
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Numerical results have been obtained for bubble growth rates in uniformly superheated aqueous solutions of ethanol by solving the extended Rayleigh equation and the equation of the bubble wall temperature derived by Plesset and Zwick, by means of a finite difference procedure. From the numerical results it is found that, as the mass fraction of ethanol is increased, the bubble growth rate first increases due to the increase in vapor pressure and then decreases due to the increase in vapor density.
Experimental data on bubble growth rates in aqueous solutions of ethanol under completely constant and uniform superheat conditions have been obtained by a unique experimental method in which the superheated condition was attained by slowly decompressing a pool of solution, and a bubble nucleus was generated on the top of the cathode wire by electrolyzing the superheated solution. In both inertia-controlled and heat transfer-controlled growth regions, the experimental data on bubble growth rates are shown to compare reasonably with both the numerical results and the authors' simplified expression derived previously for superheated pure liquids, showing that the simplified expression is generally valid for superheated solutions of volatile binary components.
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Satoru Komori, Kazutaka Takata, Masaharu Takao, Yasuhiro Murakami
1990 Volume 16 Issue 5 Pages
960-968
Published: September 10, 1990
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The effects of scale-up on flow and operating characteristics were investigated in an agitated thin-film evaporator under isothermal flows with no evaporation. The equations for the scale-up between two apparatuses with different vessel-diameters were respectively derived. The downward velocity of a fillet, the cross-sectional area of the fillet, the film thickness, the mean residence time and the power consumption were measured in both apparatuses. The results show that the values of the downward velocity of the fillet and film thickness do not change when the flow-rate per unit length and the clearance are the same between the two apparatuses with different diameters, and that the cross-sectional area of a fillet increases in proportion to the ratio of the diameters. Furthermore, it is shown that the mean residence time does not differ between the two apparatuses with different diameters when the flow-rate per unit length and the clearance are constant, and that the power consumption is proportional to the ratio of the diameters to the 5/2 power when the fluid viscosity, the rotation number, the flow-rate per unit length and the clearance are kept constant.
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Shinichi Yuu, Eiichi Karube, Takeharu Furusawa, Toshihiko Umekage
1990 Volume 16 Issue 5 Pages
969-976
Published: September 10, 1990
Released on J-STAGE: November 12, 2009
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It is important to predict the stress distribution in a powder bed for the design of storage vessels and unit operations with the powder. We calculated the stress distributions in the storage vessel by using the constitutive equation of powder based on the plastic potential and Coulomb-Mohr criteria, and the incremental finite element method. We also calculated the wall. stress distributions and compared them with our experimental results. They are in fairly good agreement with each other in the horizontal stress distribution of the side wall as well as in the vertical stress of the bottom. These results show that the constitutive equation and our simulation are reasonable and would be useful for the design of powder storage vessels. When the frictional force becomes equal to the weight of the powder at the side wall, a foot of arch forms at the point. The calculated results show the location and the formation mechanism of the foot of arch in the powder storage vessel.
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Hideharu Yagi, Chiharu Miyajima, Masahide Ishikawa
1990 Volume 16 Issue 5 Pages
977-981
Published: September 10, 1990
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To collect information on the macroattrition which is unavoidable in the crystallization of needle-shaped crystals, we stirred a suspension containing needle-shaped crystals of CaSO
4·2H
2O. Time-dependent distributions of length, breadth and elongation of crystals suggested a macroattrition mechanism in which the very slender crystals formed by longitudinal cleavage were subsequently broken. The rates of increase in number of slender crystals formed by the macroattrition were measured under various stirring conditions. They were correlated by the impeller Reynolds number.
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Hisashi Kikuchi, Takayuki Watanabe, Takuya Honda, Atsushi Kanzawa
1990 Volume 16 Issue 5 Pages
982-989
Published: September 10, 1990
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Charge and discharge heat transfer rates were investigated by using a latent heat storage reservoir with sloped distribution of m.p. The heat storage reservoir consisted of 45 vertical cylindrical capsules. The heat transfer fluid was air and paraffin wax within the capsules was the phase change material (PCM).
Melting and solidification time of the PCM were measured for three kinds of m.p. distributions. The charge and discharge heat transfer rates were estimated from the melting and solidification time respectively. Numerical results agreed with the experimental results. For the PCM with constant m.p. the charge and discharge heat transfer rates decreased downstream from the air inlet of the reservoir. The charge and discharge heat transfer rates increased by sloping m.p. distribution. The analytical investigation showed that m.p. distribution with too large or too small slope was not suitable.
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Hiroyuki Ozoe, Eiji Maruo, Hiroshi Matsuo
1990 Volume 16 Issue 5 Pages
990-997
Published: September 10, 1990
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The mathematical equations for natural convection of liquid metals in an enclosure with an external magnetic field are presented and solved numerically. After step increase in the Hartman number from 100 to 500, the direction of flow switched one by one with decrease in its strength and the flow converged to weak convection. This transient behaviour was visualized with contour maps of stream function. The effect of the magnetic Prandtl number was also studied for values from 1 to 10
4. Neither the rate of heat transfer nor the convection mode was affected by the magnetic Prandtl number, indicating the uniformity of magnetic field in the fluid regime.
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Yong-Ling He, Hirokazu Nishitani, Eiichi Kunugita
1990 Volume 16 Issue 5 Pages
998-1005
Published: September 10, 1990
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An absorption refrigeration system can be regarded as a heat exchanger network with five heat exchanger units. In this paper a static model of the system is derived, based on physical considerations. The model is composed of 44 algebraic equations with 62 variables. By using this model the operational flexibility of the system was analyzed in the uncertain parameter space. This method can be effectively used to design a flexible refrigeration system with required tolerance.
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Hirokazu Nishitani, Eiichi Kunugita, Yuan-Chen Wan
1990 Volume 16 Issue 5 Pages
1006-1012
Published: September 10, 1990
Released on J-STAGE: November 12, 2009
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In this paper, a two-step design procedure is proposed to devise a plant-wide control system for the chemical plant with strong interactive process units. In the first step a conventional control system is composed for a basic plant operation. In the second step some advanced control schemes are applied to improve insufficient control performance under the above conventional control system. As an illustrative example a candidate plant-wide control system was devised for a fuel cell power plant by the proposed method.
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Ryuzo Ito, Yushi Hirata, Akiyoshi Ohshio
1990 Volume 16 Issue 5 Pages
1013-1019
Published: September 10, 1990
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Ring vortexes which are formed in series by rotating multistage disks in a cylindrical vessel were investigated by flow visualization, torque measurement and concentration response. The vortex behavior, visualized using aluminum powder, is described in the laminar, transition and turbulent states. The critical Reynolds number for the onset of interface oscillation of laminar vortexes is related to the gap width between the rotating disk and vessel wall. Average torque acting on a disk is correlated in terms of the torque coefficient. It was confirmed in a dye experiment that the model of perfectly mixed tank in series is applicable to characterizing the intermixing through the vortex interface. Using this model the intermixing rate was evaluated. The rate through the injection interface is greater than that through the suction interface and the rate in the turbulent vortex varies in proportion to Kolomogoroff's velocity scale. Empirical correlations are given for the intermixing rate and the Reynolds number indicating the transition to turbulent interface.
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Masakazu Sasaki, Shigeki Takishima, Hirokatsu Masuoka
1990 Volume 16 Issue 5 Pages
1020-1028
Published: September 10, 1990
Released on J-STAGE: November 12, 2009
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Experiments in removing volatile residues using supercritical carbon dioxide were carried out for three systems : benzene+poly (vinyl acetate), toluene+poly (vinyl acetate), and benzene +polystyrene, at 313K and 7.95MPa. The removal rate of benzene or toluene for the benzene or toluene + poly (vinyl acetate) systems was found to be faster than in the benzene+polystyrene system. This was explained by the difference of plasticity and dissolution rate of carbon dioxide between poly (vinyl acetate) and polystyrene. In the benzene+polystyrene system, the removal ratio by extraction was increased with increase in the initial concentration of benzene. It was considered that plasticization with increase in initial benzene concentrations affected the removal ratio by extraction. Also, it was shown that the removal ratio by decompression was increased with increase in the quantity of carbon dioxide dissolved in the polymer.
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Masakazu Sasaki, Shigeki Takishima, Hirokatsu Masuoka
1990 Volume 16 Issue 5 Pages
1029-1037
Published: September 10, 1990
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A mass transfer model for estimation of extraction quantity of benzene from poly (vinyl acetate) was developed by considering the influence of the quantity of carbon dioxide dissolved in the polymer on the diffusion coefficient of benzene in the polymer and the dilation of the polymer. To confirm the validity of this model, simulations of extraction experiments of benzene from poly (vinyl acetate) at a temperature of 313K and a pressure of 7.95MPa were carried out. The mass transfer model proposed in this paper explains the experimental results with fairly good accuracy, compared with the previous model in which the mass transfer phenomena of benzene were treated as diffusion of benzene in the polymer saturated with carbon dioxide immediately after the beginning of experiments.
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Makoto Nishimura, Yoshiyuki Bando, Hiroyuki Sota, Masahito Hayashi, Mi ...
1990 Volume 16 Issue 5 Pages
1038-1044
Published: September 10, 1990
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The effect of the number and setting position of the transparent partitioning films on the collection characteristics of the “Volume Heat Trap” solar collector was studied theoretically and experimentally.
For stagnant collectors with transparent partitioning films, the time changes of temperature distribution were measured in indoor experiments. Results calculated with consideration of the natural convection within the working fluid layer were compared with the experimental data.
It was found that this theoretical analysis was valid. With increasing number of partitioning films, up to the critical number (thickness) for the perfect suppression of natural convection, the degree of suppression of natural convection became larger and the collection efficiency increased. The critical thickness for the perfect suppression of natural convection increased with increasing viscosity of working fluid and with decreasing total incident radiation. When a single partitioning film was set, an optimum setting position for the collection efficiency existed and the thickness of the upper fluid layer was equivalent to the critical thickness for the perfect suppression of natural convection.
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Eiichi Kunugita, Jong-Hwa Kim, Isao Komasawa
1990 Volume 16 Issue 5 Pages
1045-1052
Published: September 10, 1990
Released on J-STAGE: November 12, 2009
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A process was studied for recovery and purification of lithium from hot spring water and leachate of coal fly ash in which lithium is present at very low concentration in a mixture of high concentration of less desirable species such as alkali metals, alkaline earth metals and others. Lithium is, as a first step, adsorbed selectively by an ion-sieve type adsorbent, λ-MnO
2, which can effect separation by adsorbing lithium alone in its intraparticle spaces while adsorbing most metals on its surface. Stagewise elutions are performed, employing two elutrients : NH
4NO
3 and then HNO
3 solution. The concentration ratio of lithium and sodium is 1/701/120 in the original feed stream, and this is upgraded to 300/1 in the pregnant elutrient.
Some impurities in the pregnant elutrient is removed by a solvent extraction technique, employing a mixed extractant of a β-diketone (LIX51) and tri-
n-octyl-phosphine oxide in kerosene. A lithium solution with an undetectable amount of impurities is obtained by single extraction followed by single scrubbing with dilute hydrochloric acid of carefully controlled concentration.
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Ryoichi Kuboi, Hisakazu Tanaka, Isao Komasawa
1990 Volume 16 Issue 5 Pages
1053-1059
Published: September 10, 1990
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The effect of the presence of salts of high concentration in aqueous two-phase systems as a phase-forming salt or a modifier on the hydrophobicity of the systems has been studied, employing several amino acids with various relative hydrophobicities as solutes. The hydrophobicity of the system can be expressed by
HF (hydrophobic factor) in the presence of salts of high concentration and in the range of pH apart from pI of the solute.
In the PEG/PK (potassium phosphate) system, an increase in pH of the system caused by selection of the ratio of K
2HPO
4 and KH
2PO
4 results in an increase in the hydrophobic factor of the system. The partition of amino acids is dominantly governed by the hydrophobic interaction in the range of pH<8, while an electrostatic interaction (Donnan effect) starts to contribute in the range of pH>9. In the PEG/ MgSO
4 sysyem, addition of salts such as Na
2SO
4 and sodium phosphate considerably increases the hydrophobic factor, while LiCl decreases it. All data of
HF can be correlated with a simple relation with concentration difference of PEG in the two phases, and therefore the variation of the hydrophobicity of the systems can be correlated with the variation of composition of the phase systems.
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Ryoichi Kuboi, Yoshiaki Mori, Isao Komasawa
1990 Volume 16 Issue 5 Pages
1060-1066
Published: September 10, 1990
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Reverse micelle extraction of porcine pancreas lipase was studied, focusing on activity yield or denaturation of the lipase as well as its fraction extracted. On the fraction extracted of the lipase, the effect of size exclusion and hydrophobic interaction are more important than that of electrostatic interaction due to the relatively high molecular weight and strong hydrophobicity of the lipase. The lipase can be solubilized into micellar phase up to 30 % in a two-phase extraction system in which two bulk solutions contact through a flat interface. The activity yield is, however, found to be very poor in this extraction system. This is related to a noncompetitive strong interaction between the lipase and anionic detergent AOT in the extraction and stripping processes.
A feasible extraction system is the injection method, in which a small volume of concentrated lipase solution is mixed vigorously with micellar solution and the extraction is completed in a few seconds. An addition of adsorbents for AOT into stripping solution can be used for the stripping to reduce the inevitable interaction between the lipase and AOT.
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Jusuke Hidaka, Atsuko Simosaka, Hideaki Ito, Shigeo Miwa
1990 Volume 16 Issue 5 Pages
1067-1073
Published: September 10, 1990
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Effects of particle properties and number of particles on the parameters of sound from the collision between particles and a circular plate is discussed, in relation to measuring particle size and flow rate by the parameters of the impact sound.
The sound pressure is proportional to the number of particles colliding with the plate, and the characteristic frequency of the sound relates to the particle diameter. Moreover, particle size distribution can be measured by the intensity of the characteristic frequency component of each particle diameter.
These results show that the particle size distribution and the mass flow rate of particles can be measured instantaneously by the parameters of impact sound between particles and a circular plate.
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Michitaka Suzuki, Yukitoshi Nakatsuji, Mitsuaki Hirota, Toshio Oshima
1990 Volume 16 Issue 5 Pages
1074-1079
Published: September 10, 1990
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Fine powders with log-uniform or Andreasen (Gaudin-Schuhmann) size distribution were prepared by mixing of mono-sized alumina powders (50% diameter 110 μm), and the compressive property of the powder beds was measured using a uni-axial piston press. From our experimental results void fraction of the pressed powder beds is affected by size distribution, and the value of the Fuller constant at minimum void fraction of a bed with Andreasen distribution is about 1.0. For log-uniform distribution the value of void fraction decreases with decreasing inclination of size distribution. The experimental void fractions were compared with the estimated values by modified equations based on our proposed model for a multi-component particle mixture. The agreement between them was fairly good in both distributions.
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Masami Furuuchi, Takahiro Fukagawa, Yoshihiro Suzuki, Keishi Gotoh
1990 Volume 16 Issue 5 Pages
1080-1086
Published: September 10, 1990
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The electrical conductivity of suspensions of binary mixtures of particles having different shapes is investigated experimentally and theoretically. First, the effective conductivity of suspensions of equal particles is measured and compared with available theoretical relations. It is found that in the high concentration region of particles, the effective conductivity is significantly affected by the particle orientation and the short circuit due to contact between conducting particles. Next, the effective conductivity of suspensions of binary particle mixtures is theoretically related to the shape and conductivity of each component, the mixture ratio and the total particle volume fraction. The relation of Eq. (14) with Eq. (17), is in agreement with the experiments.
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Yasuhide Nishi
1990 Volume 16 Issue 5 Pages
1087-1093
Published: September 10, 1990
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A pipeline network consists of a number of source points, consumption points and candidate pipes connecting these points. An original pipeline has been constructed and the amount of supply increases. Therefore, it is required to reconstruct the existing pipeline.
This paper describes an algorithm to determine the improved pipeline route that minimizes additional cost. The algorithm consists of a step that determines a starting solution and a step that adjusts the solution. The algorithm can be applied to various cost models and objective functions, and a rather large-scale network can be treated by use of a personal computer. An example is also presented.
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Shigeaki Kasaoka, Eiji Sasaoka, Makoto Hanaya
1990 Volume 16 Issue 5 Pages
1094-1100
Published: September 10, 1990
Released on J-STAGE: November 12, 2009
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To establish a catalytic process for the steam-reforming of methane, Ni, Ru and Rh catalysts supported on MgO, θ-Al
2O
3, La
2O
3, ZrO
2 and. SiO
2 were prepared and the relationship between the reaction condition and the catalytic performance was studied. Furthermore, a reaction scheme was proposed from characterization with the temperature-programmed reaction method..
Eeperiments were carried out using a fixed-flow bed reactor under atmospheric pressure and at 500°900°C. The inlet gases were mainly 20% CH
4-40% H
2O-N
2, the total flow rate was 500 cm
3·min
-1 per 0.25 ml of each catalyst with average diameter of 1.0 mm and the space velocity was 1.2× 10
5h
-1.
The main results obtained. were as follows : (1) θ-Al
2O
3 was superior as the support. (2) The activity difference was very small among Ni (15wt%) /θ-Al
2O
3, Ru (5wt%) / θ-Al
2O
3 and Rh (5wt%) / θ-Al
2O
3, but the order of apparent activity was Ni>Ru> Rh. (3) It was proved that H
2 and CO
2 were primarily produced from methane and CO was secondarily produced by the reduction of CO
2 with H
2. (4) It was suggested that CO
2 was produced through surface carbon.
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Atsushi Ikari, Yasuo Hatate, Katsuyoshi Yanagida, Michiharu Eta
1990 Volume 16 Issue 5 Pages
1101-1104
Published: September 10, 1990
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Vapor-liquid equilibria of aqueous ethanol solutions containing a minute amount of
n-propyl alcohol, isobutyl alcohol and isoamyl alcohol were measured by use of an Othmer-type still at 12.7, 25.3 and 101.3 kPa. The equilibrium ratio of the trace components decreases with decreasing pressure.
The equilibrium ratio curves of the trace components at each pressure are represented by a function of the concentration of ethanol.
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Atsushi Ikari, Yasuo Hatate, Seiichi Sakaue, Nozomu Matsuzaki
1990 Volume 16 Issue 5 Pages
1105-1109
Published: September 10, 1990
Released on J-STAGE: November 12, 2009
JOURNAL
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Vapor-liquid equilibria of the following systems, in which the mark * indicates a trace component, were measured by use of an Othmer-type still at 0.667, 2.67, 8.00 and 16.0 kPa : (1) aniline-tetralin
* system, (2) aniline-phenol
* system, (3) tetralinphenol
* system, and (4) tetralin-aniline-phenol * system.
The equilibrium ratios of tetralin
* in aniline and phenol
* in tetralin and aniline become constant in the range of concentration below about 0.005 mole fraction in liquid phase.
It is shown that the equilibrium ratio of phenol
* in tetralin and tetralin-aniline mixtures decreases with decreasing pressure, but the equilibrium ratio of tetralin
* in aniline increases with decreasing pressure.
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Hideo Shidara, Motokazu Kikuchi, Mikio Kanzaki, Masafumi Kuriyama, Hir ...
1990 Volume 16 Issue 5 Pages
1110-1113
Published: September 10, 1990
Released on J-STAGE: November 12, 2009
JOURNAL
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Experimental studies of heat transfer and pressure drop in a plate-type heat exchanger were carried out for pseudoplastic fluids.
Representative values of shear rate and apparent viscosity in the exchanger were estimated by a simple model. It was found that the previous correlations of heat transfer coefficient and pressure drop for Newtonian fluid can be extended to pseudoplastic fluids by the introduction of these representative values.
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Motoyuki Hanawa, Naotake Katoh
1990 Volume 16 Issue 5 Pages
1113-1116
Published: September 10, 1990
Released on J-STAGE: November 12, 2009
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Chemical plant operations are now becoming more advanced, making process control more difficult by conventional control alone, The zone melting process, which is a typical example of advanced chemical process operation, has strong disturbances due to the movement of a sample tube or heaters and to interactions between heaters.
In this work, an optimal regulator was applied to a simple anthracene zone melting process and the experimental results showed good control performance. This result suggests that the production rate of the zone melting process can be imporved.
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Mitsuytki Nakajima, Daisuke Hirota, Ryohei Yamazaki, Genji Jimbo
1990 Volume 16 Issue 5 Pages
1117-1120
Published: September 10, 1990
Released on J-STAGE: November 12, 2009
JOURNAL
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Solid flow behavior was examined in fluidized beds without internals and those with ring-shaped baffles which had small cross-sectional area. The following results were obtained.
(1) The solid circulation patter was changed by installing baffles. Hower, the mean velocity of descending solids was unchanged.
(2) For Geldart's B powder, the mean velocity of descending solids was well correlated by the following equation.
vd=26.9× (ρ
p)
-0.5× (
u-umf) ×exp (-2.87×103×
dp)
where ρ
p is particle density in unit of kg/m
3,
u superficial gas velocity,
umf minimum fluidizing velocity and
dp median particle diameter in unit of
m.
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Simulation using a two box model
Atsushi Inaba, Yuji Shindo, Hiroshi Komiyama
1990 Volume 16 Issue 5 Pages
1120-1124
Published: September 10, 1990
Released on J-STAGE: November 12, 2009
JOURNAL
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The material balance of carbon at steady state in the ocean was analyzed using a two box model, in which the fixation of carbon by the plant biota and the transportation of carbon by the upflow of water were taken into account. The difference between the rates of fixation of inorganic carbon and decomposition of organic carbon was calculated by the material balances of carbon and
14C. The sedimentation speed of CaCO
3 and POC was estimated, and a correlation of the concentrations with respect to DIC, TOC and CaCO
3 at the surface and in the deep sea was presented. From the calculation result, the important role of the plant biota in the carbon cycle of the ocean was shown quantitatively.
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Akira Suzuki, Tadashi Nakamura, Shinji Itoh, Shin-ya Yokoyama
1990 Volume 16 Issue 5 Pages
1124-1128
Published: September 10, 1990
Released on J-STAGE: November 12, 2009
JOURNAL
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The reaction product obtained from direct thermochemical liquefaction of sewage sludge is a mixture of heavy oil, char and aqueous phase. The heavy oil must be separated from the product if it is to be used for boiler fuel and other applications. High-pressure distillation (573K-8.8 MPa) was evaluated as a means of isolating heavy oil from the product. As a result, heavy oil suitable for use as fuel was obtained. This distillation method is a promising technique for oil separation from the liquefaction product of sewage sludge.
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Setsuji Tone, Teruyuki Masawaki, Hiroshi Osamura, Hironobu Taguchi
1990 Volume 16 Issue 5 Pages
1128-1131
Published: September 10, 1990
Released on J-STAGE: November 12, 2009
JOURNAL
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A rate analysis of photoisomerization of norbornadiene to quadricyclane in solution was performed under complete absorption of light. The rate of photoisomerization reaction was independent of concentration of photosensitizer and reaction temperature. The reaction was zero order with respect to concentration of norbornadiene and first order with respect to light intensity, and was described by
dCQ/dt=
k'μIawhere
k' is an experimental constant that was found to be identical with quantum yield. The maximum quantum yield was obtained when the reaction was carried out using benzophenone as a photosensitizer in cyclohexane.
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