-
Yoshinari Hori, Akihiro Yamada, Makoto Shimoda, Masaaki Bannai, Koichi ...
1996 Volume 22 Issue 4 Pages
695-701
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Recently, district heating and cooling (DHC) plants with heat storage tanks have become common. But the optimization of the operational planning for these systems requires much computation time. In this paper, an optimal planning method for operation of these systems using a genetic algorithm (GA) was proposed. The proposed method has three new characteristics. Firstly, the optimization of DHC plant operation schedule to minimize both running costs and the dynamic load variation can be obtained. Secondly, it makes the search for optimal value more effective to use operator's know-how. Lastly, the probabilities of “crossover” and “mutation” can be changed dynamically to avoid converging to a local minimum value. Simulations demonstrated that the proposed method gives ten times faster computation time of dynamic programing needed to obtain the minimum operation cost and small load variation.
View full abstract
-
Hideo Miki, Yoshio Aoyama
1996 Volume 22 Issue 4 Pages
702-706
Published: July 10, 1996
Released on J-STAGE: February 19, 2010
JOURNAL
FREE ACCESS
For the clarification of crystallization conditions to obtain agglomerated crystals of spherical MnCO
3 having high purity and high packed density, the reactive crystallization with MnSO
4 and (NH
4)
2CO
3 solutions in high concentration was carried out using a pilot mixing crystallizer. The crystallization method to obtain spherical and compact agglomerated crystals was determined by applying conditions in which the nucleation rate was made high by the high degree of supersaturation and nuclei were agglomerated in the agglomeration zone in the crystallizer. Furthermore, for the production of agglomerated crystals having packed density larger than 2.6 g/cm
3, the mixing of coarse crystals obtained from the crystallizer bottom with fine crystals in the over flowing solution at the weight ratio of 7 : 3 was found to be suitable.
View full abstract
-
Takahiro Oshita, Shuichi Nagato, Norihisa Miyoshi, Shugo Hosoda
1996 Volume 22 Issue 4 Pages
707-713
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
In an ICFB boiler, the fluidized bed is separated by a partition into the main combustion and the heat recovery chambers. The flows in these chambers are generated by using silica sand as the fluidizing medium. To determine the overall heat transfer coefficient (HTC) of the boiler's panel type immersed heat transfer tubes, combustion tests were performed with wire rim tires. The overall HTC of a panel tube array was lower than that of a zigzag tube arrangement. In practice, the heat absorbed by the fins makes the coefficients of either type of tube array almost identical. The air flowrate in the circulating bed at the bottom of the heat recovery chamber can be changed to control the overall HTC to a value virtually identical with that of a zigzag tube array. The combustion of wire rim tires leads to a buildup of wires in the zigzag array. hampering the transfer of heat. Yet, the panel type array showed no buildup so that it was possible to maintain steady operation with this type of tube arrangement.
View full abstract
-
Tatsuo Go, Toshitaka Hara, Munetaka Honda, Kunio Kato
1996 Volume 22 Issue 4 Pages
714-721
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The production process of perovskite-structive titanium dioxide for of electronic materials was developed and analyzed quantitatively. In the production of titanium dioxide by the CVD method the fine powder is synthesized by the reaction of titanium tetrachloride with oxygen at high temperature.
The production process of the titanium dioxide was investigated using pilot scale apparatus. Consequently, the reaction conditions suitable for powder production with uniform size are turbulent diffusion combustion between the titanium tetrachloride and the oxygen.Using this result, reasonable reactors can be designed.
A fine powder of high purity titanium dioxide with sharp particle size distribution is produced by this process. We confirmed that this vapor phase oxidation process could be applied to the production of other ceramics.
View full abstract
-
Fujio Watanabe, Jun Kozuka, Mutsuhiro Ito, Masanobu Hasatani
1996 Volume 22 Issue 4 Pages
722-727
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The possibility of producing cold heat energy by the super active carbon/ethanol-adsorption heat pump (AHP) with the packed bed type adsorber was discussed on the basis of both experimental and calculated results of the transient behavior accompanied by this operation.
The trend of experimental results for heat and mass transfer agrees well with computer simulation under closed-system, one-component, non-isothermal conditions in both adsorption and desorption processes. The super active carbon/ethanol-AHP proposed generates high level cold heat energy by raising the desorption temperature. Therefore, this AHP is applicable to a refrigerator. However, it is suggested that enhancement of heat tranfer in the adsorber is indispensable to obtain high power energy from this type of AHP.
View full abstract
-
Toshiyuki Maeda, Michio Saito, Hiroyuki Fujimoto, Yushi Hirata
1996 Volume 22 Issue 4 Pages
728-734
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Pitch fluoride is a new fluorine-carbon compound which has an excellent water repellency with a contact angle of more than 145 degrees, thermal resistance and high solubility in some fluoro solvents. In this study, various types of coal tar pitch were directly fluorinated by fluorine gas in order to prepare pitch fluoride at temperatures ranging from 50°C to 130°C. Depending on the softening point of each raw pitch, an optimum reaction temperature exists, at which pitch fluoride was synthesized at 200% increase in weight without decomposition of -C-C- bonds, and it was found that pitch with a high softening point is suitable as a raw material for synthesis.
View full abstract
-
Osamu Miyatake, Hiroki Morita, Katsushi Uryu, Tsutomu Yonemori
1996 Volume 22 Issue 4 Pages
735-741
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
This report deals with an experimental and numerical analysis carried out to investigate the discharge characteristics of latent heat storage columns, by using cross-linked cylindrical plastic particles as a phase-change type of heat storage material and ethylene glycol as a heat transfer medium. In the experiment, the transient response of the outlet temperature of heat transfer medium was measured under conditions of varying the initial temperature in the column, the inlet temperature of heat transfer medium, the mass flow rate of heat transfer medium, and the mass of heat storage material packed in the column.In the numerical analysis, the transient temperature distribution in the column was calculated by using the empirical formula for estimating the heat transfer coefficient for a fixed bed, which was recommended in the authors' previous report. The experimental results were found to be in fair agreement with numerical results.
View full abstract
-
Hajime Ino, Koichi Tabei, Masao Fujishige, Mitsunori Hozawa
1996 Volume 22 Issue 4 Pages
742-749
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
An experimental work of copper extraction using a tank of 35 dm
3 (liquid volume 16 dm
3) volume was carried out for the scale-up of a stirred tank extractor for a liquid surfactant membrane process. In the experiment, kerosene solution containing 17 vol. % Span 80 and 110 wt. % LIX 64 N was used as the oil phase. 15.7 mol·dm
-3 copper sulfate solution of pH 5.4 and 0.38 mol·dm
-3 or 0.5 mol·dm
-3 sulfuric acid solution were used as the outer and the inner aqueous phase, respectively. The extraction rate, the break up ratio of the W/O emulsion, and the mechanical entrainment were measured. As a result of a small scale volume, the extraction rate was expressed by the following Equation
- (
d ln
Ccu·out/
dθ) =
k'
CL·
Cs-0.32·
We0.3/ (C
H+)
0.5Where
k'= 6.9× 10
-5m
1.5·mol
-0.5·s
-1Ccu·out is copper concentration in the outer aqueous phase,
CL is weight fraction of extractant in kerosene,
Cs, is volume fraction of surfactant in kerosene, θ, extraction time,
We, Weber number,
D, diameter of impeller,
N, agitation speed, ρ
c, density of outer water, σ, surface tension and C
H+ is concentration of hydrogen ion. The optimum conditions of a middle scale tank were as follows, (1) agitation speed is 2.8 s
-1, (2) pouring rate of the emulsion should be less than 8.33 cm
3·s
-1, (3) surfactant concentration is 2 vol. % (about 2.5 wt. %), (4) extractant concentration is 3 wt. %.
Under optimum conditions, more than 99.9% of copper in the feed solution was extracted in 10 min., the break up ratio was less than 2% and the mechanical entrainment was less than 8 vol. %. The extraction rate was expressed by the same equation as in the small scale. The entrainment occurred mainly in the phase separation.
View full abstract
-
Shin'ichi Kishimoto, Toshiya Tanabe, Shougo Maruyama, Akihiro Kishishi ...
1996 Volume 22 Issue 4 Pages
750-755
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Desolvation of L-histidine and α-ketoisocaproic acid complex from ethanolate crystals was investigated. The ethanolate crystals were obtained from ethanol aqueous solutions of above 60 wt% of ethanol. It was difficult to remove ethanol molecules from the crystals by vacuum drying. However, it was found that ethanol molecules in the crystal lattice could be released under humidified conditions, for example, 313 K and 60 % relative humidity, accompanied by transformation to non-solvated crystals. When the peak of 2θ=9.0° (CuK
α radiation) in powder X-ray diffraction pattern of the ethanolate crystals was weak, ethanol molecules (about 1 wt%) remained in the crystals at the end of transformation, and then the residual ethanol decreased slowly. A controlled moderate cooling process, where the supersaturation is released slowly, is the key point to obtain ethanolate crystals having high “crystallinity” (defined as peak height of 2θ= 9.0°) which shows quick desolvation rather than adding ethanol for a rapid increase of supersaturation in crystallization.
View full abstract
-
Kaoru Kimura, Hiroshi Takahashi
1996 Volume 22 Issue 4 Pages
756-762
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The efficiency of granular bed filters and a critical operational condition due to particle entrainment from the filter were studied. The subject of the present study was concerned with the filtration of highly concentrated dust particles, in which the dust entrainment takes place dominantly at the very beginning of filtration. A model has been proposed to describe the filtration process accompanied by dust capture and reentrainment, based on the evaluation of drag force acting on particles in contact with a granule. Since, in the model, the granular bed filter was regarded as consisting of apparent partial filters in series, the local amount of deposited dust and therefore partial efficiency could be predicted. Removal of fly ash was carried out using spherical granules at constant filtration rate. The overall efficiency of the filter was lower at higher gas flow rate, although the filtration proceeded in the range that the effect of inertial impaction is dominant. The decrease of the efficiency has been related to the degree of particle reentrainment. The model was verified with the experimental results obtained under various conditions of gas velocity, granule diameter and filter thickness, and was effective to explain the decrease of collection efficiency with dust load.
View full abstract
-
Tamio Noda, Tatsuya Kanamaru, Shigeru Maeda
1996 Volume 22 Issue 4 Pages
763-769
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
A deodorant filter was made by treating porous metallic iron with an L-ascorbic acid aqueous solution, depositing the iron ascorbate on it. The ammonia adsorption capacity of the deodorant filter was studied with repetitive runs of adsorption tests. The results show that the ammonia adsorption capacity of the iron ascorbate is nealy equal to conventional granular activated carbon at the beginning, but unlike the letter, the iron ascorbate perfectly recovers the capacity via reversible desorption. ESR and Mossbauer spectroscopy reveal that ammonia goes into the inner coordination sphere of Fe (II) and Fe (III), capable of reversible adsorption and desorption, and that the reactivity of iron is attributable to the formation of the ascorbate complex, which is formed in the specific manufacturing process of the deodorant filter.
View full abstract
-
In case of Concentration Controls in Resources Processing
Seiji Matsuo, Yasuhiko Okano
1996 Volume 22 Issue 4 Pages
770-776
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The linearization method recently highlighted has been successfully applied in designing an optimal or a flexible control system of a bilinear process actually encountered in case of concentration controls in resources processing.
The purposes of the study were to eliminate dependency of control performance upon set point values, to compensate inverse responses of the plant and to extend an allowable range of set point values to be changed.
As the plant had to be approximated prior to application of the method, the modelling error was to be considered in the following design stage of a linear controller. Furthermore, state variables were estimated on an approximate nonlinear observer obtained by an extended linearization method, as the variables concerned here could not be detected.
The results have been shown in the figures which were obtained exclusively by computer simulations.
View full abstract
-
Yasuhiro Imamura, Satoji Kobayashi, Hikoji Inazumi
1996 Volume 22 Issue 4 Pages
777-785
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The relationship between the gas-liquid two phase flow and the formation of dead space in the throat of a horizontal ejector with liquid jet was investigated experimentally.
The flow modes in the throal can be classified approximately into three regimes which present a different kind of bubble formation and gas-liquid mixing. The relationship between the values of pressure in a chamber of the ejector, P
s, and the principal operating factors was investigated in the case of single and multi nozzles. As a result, an empirical correlation by which the observed values of
Ps can be predicted within an error of ±5% was obtained.
The relationship between the start points of bubble formation in the throat, Lc, and the operating conditions was also investigated. As a result, two empirical correlations by which the observed values of
Lc can be predicted within an error of ±25% were obtained for single and multi nozzles.
Moreover, experimental data were investigated from the view point of the relationship between flow pattern and longitudinal distribution of the static pressure. As a result, a characteristic curve by which the observed flow patterns can be predicted was obtained.
View full abstract
-
Shigeru Mori, Mikio Kumita, Akira Tanimoto, Junchen Lu
1996 Volume 22 Issue 4 Pages
786-793
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
An electric potential field in an electrolytic bath that contains electrodes of various geometric shapes for pulse plating was numerically analyzed by using the finite element method, and dimensionless thickness distribution of metal deposit on the cathode was estimated from the potential distribution in the bath. Relations between the potential distribution in the bath and the thickness distribution of metal deposit were investigated on the basis of both calculated results and experimental data for pulse plating of copper. Moreover, an improvement in leveling of the pulse-plated metal deposit was discussed.
The calculated results of dimensionless thickness distributions of metal deposit on the cathode agreed with the experimental ones, showing the validity of the numerical analysis employed in this work. Relations between the thickness distributions of metal deposit and the geometric factors such as distance between the electrodes, size and shape of the electrodes were quantitatively clarified by the present numerical analysis. Furthermore, by including cutoff plates near the cathode, the electric potential field in the bath could be controlled, and leveling of the pulse-plated metal deposit was also improved effectively.
View full abstract
-
Toshiro Tsuji, Toshiharu Shibata, Hironori Itoh, Osamu Uemaki
1996 Volume 22 Issue 4 Pages
794-800
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The steam gasification of Taiheiyo coal char was carried out to determine gasification kinetics taking account of the concentration dependence of coexisting gases of H
2, CO
2, CO and O
2. Gasification tests were conducted with five different gas mixtures as gasifying agents at atmospheric pressure and over a temperature range of 1073 to 1273 K using a differential fixed bed reactor. The reaction rate equation was expressed by such functions as temperature, partial pressure of the gases, changes of pore structure and surface area of char and the unconverted carbon fraction of the char. The dependence of the gasification rate on the partial pressure of H
2O, CO
2 and CO was able to be expressed by Langmuir-Hinshelwood kinetics which accounts for the decrease in the rate due to coexistence of H
2 and CO. The partial pressure of CO
2 had little effect on the rate in the H
2O-CO
2 gasification because the reaction rate of H
2O is greater than CO
2. It was seen that the reaction rate of the char with O
2 depends on the diffusion coefficient of O
2 in the mixed gas. The rate equation based on the shrinking sphere model was in good agreement with the experimental result. The dependence of the steam reaction rate on the unconverted carbon fraction of partially burned char is almost the same as that of the char before burning.
View full abstract
-
Osamu Uemaki, Masahiro Kikuchi, Kazuaki Matsushita, Toshiro Tsuji, Tos ...
1996 Volume 22 Issue 4 Pages
801-807
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Cellulase was immobilized on alumina particles for use in fluidized bed type reactors by physical adsorption, cyanogen bromide activation, and cyanogen bromide activation with spacer. Hydrolysis of Avicel was carried out at 50°C and pH 4.5 using these immobilized cellulase (IMC) and the effects of the immobilization method on the reaction performance were investigated. Dependence of the IMC activity on temperature and pH were not altered, as compared with free cellulase. The activity was strongly influenced in the hydrolysis of water-insoluble substrates by the preparation method for immobilizing cellulase. The highest activity was achieved for the IMC prepared by the cyanogen bromide activation with spacer and these values were about ten times greater than the lowest activity for the physical adsorption. Although the activity decreased significantly over the initial reaction period the IMC provided good stability during the reaction, as compared with free cellulase.
View full abstract
-
Hirotaka Yoshida, Yoshinori Itaya, Masanobu Hasatani
1996 Volume 22 Issue 4 Pages
808-814
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
This paper proposes to use microwave heating in molding processes of resin powder for improving the heat efficiency and reducing the processing time. Simple measurement methods of distributions of electric field intensity in various types of cavities and loss coefficients of resin powder with multicomponents were developed. The electric field intensity can be determined from the rising rate of temperature of water whose loss coefficient is known. This measurement showed a large distribution of electric field intensity in a cavity, but the distribution was improved by the stirring of a fan. The microwave absorption performance of the powder resin of a PVC base is superior to the pure PVC since it is much influenced by the plasticizer contained in the sample than PVC itself. The preheating of the sample enhances the energy absorption and it may allow the processing time to be reduced considerably. The loss coefficients of the samples are measured by the method proposed in this work. The effect of additives on the loss coefficient of the samples consisting of multicomponents is studied as well, and it is implied that the apparent coefficient is not successfully correlated in simple proportion to the weight and the loss coefficient of each component.
View full abstract
-
Eiji Nakanishi, Seizou Isobe, Takeichiro Takamatsu, Hiroaki Yasuoka, H ...
1996 Volume 22 Issue 4 Pages
815-821
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The so-called allocation or partitioning problem which is still indeterminable in life cycle assessment (LCA) has been studied. The φ balance defined in this study is used to describe the relations of inputs and outputs in each subsystem consisting of the whole environment system. In doing so, the mass balance of pollutant materials in environment system under consideration is expressed in much smaller dimension compared to the case where the conventional mass balance is employed and thus the mathematical procedure is highly simplified in establishing a computer program for calculating the cumulative CO
2 emission unit which is equivalent to the total quantity of CO
2 emitted to the atmosphere to produce the present material or energy from raw fossil resources. The cumulative CO
2 emission unit which is an indicative value of CO
2 pollution used in this study of LCA are calculated for some petrochemical materials for plastics depending on several kinds of partitionings.
View full abstract
-
Toyozo Hamada, Shuji Nakatsuka, Teruyuki Masawaki, Masahito Taya, Sets ...
1996 Volume 22 Issue 4 Pages
822-829
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Separation performance of water from various alcohol-water mixtures by pervaporation was examined using a polyion complex membrane. The alcohols used in this study were ethanol, 1-propanol, 2-propanol and 1-butanol. Both permeate fluxes of water and alcohols increased with increasing mole fraction of water in the feed solution. The values of permeate fluxes of water were almost the same for all alcohols tested, while those of alcohols decreased with increasing the number of carbon in the alcohol molecule. The solubilities of water and alcohols to the membrane were also examined by sorption experiment.
The permeate fluxes of water and alcohols were analyzed on the basis of the solution-diffusion model considering the swelling of membrane caused by water. Permeate fluxes of water and alcohols were significantly affected by the degree of membrane swelling. Both solubility and diffusibility of water were larger than those of alcohols. Solubility and diffusibility of alcohols were reduced as the number of carbon in alcohol molecule increased.
View full abstract
-
Toshiyuki Teshiba, Masaharu Takao, Satoru Komori, Yasuhiro Murakami, H ...
1996 Volume 22 Issue 4 Pages
830-836
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The motion of grinding media was visualized on three types of blade (normal disk type, hole disk type and cross type) for a horizontal type sand mill of which internal blade and external cylinder rotate inversely and independently. As a result, the effect of blade geometry on velocity distribution, the intensity of velocity fluctuations and appearance frequency of grinding media was made clear. The relationship between these flow characteristics and grinding rate was discussed by carrying out grinding tests of calcium carbonate. As a result, it is found that the grinding characteristics obtained for each blade in both rotation methods can be well correlated with the intensity of velocity fluctuations weighted by appearance frequency.
A new type of blade (cross turbine type) was produced based on the above information, and its grinding rate was investigated in connection with the motion of the grinding media. The results showed that it has a higher rate of grinding than the three types of blades previously used.
View full abstract
-
Hiroyoshi Kim, Tatsuo Kanki, Tsuyoshi Asano
1996 Volume 22 Issue 4 Pages
837-845
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Interfacial tensions of D 2 EHPA in benzene/aqueous solution systems were measured by the Wilhelmy plate method. Measurments were carried out for a metal ion-free system and for a system with cupric or ferric ion dissolved. In consequence, it is made clear that 1) the adsorption process is very rapid and the extractant can exist as a monomer or its dehydrogenized anion at the interface, 2) in cupric ion extraction systems, 1 : 2 complexes are formed but no intermediate metal-ligand complexes can exist at the interface, and 3) in ferric ion extraction systems, 1 : 2 intermediate complexes are formed and can adsorb with monomer extractants at the interface. The respective actual behaviors of the interfacial tension are shown to be explained well by Gibbs equation with the aid of the reaction model deduced from present experimental insights.
View full abstract
-
Takeshi Fujiwara, Takeshi Tsushi, Hirokazu Nishitani
1996 Volume 22 Issue 4 Pages
846-853
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Some process variables measured in a plant are strictly constrained by the material and heat balance equations, rate equations and correlations. In this study, we propose a method to judge whether the state of plant operation is normal or not, by examining whether a set of process variables maintains the functional relationship specified at normal operation. The functional relationship at normal operation is identified by an autoassociative neural network (AANN) which approximates the identity mapping for a set of measured values of process variables. An effective method to search for an adequate configuration of the AANN is also presented. Abnormal operation or fault is detected by the magnitude of discrepancy between the input vector and the output vector of the trained AANN. This fault detection method is applied to a continuous flow polymerization process and compared with the conventional 3 sigma fault detection method for a single process variable.
View full abstract
-
Hideo Nakakura, Masao Sambuichi, Kunihisa Osasa
1996 Volume 22 Issue 4 Pages
854-860
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The separation characteristics and the pressure drop for deep bed filtration of heavy oil/water emulsion were experimentally investigated with granular beds of glass beads and Toyoura sand. A mathematical model for calculating the separation process was proposed on the basis of deep bed filtration theory. The filter coefficient was correlated by empirical formulas with particle diameter, particle shape factor and superficial velocity. Furthermore, a calculation model was presented for estimating the pressure drop and the hydraulic pressure distribution in granular beds by considering the deposition change of oil droplets in the pores calculated by both the deep bed filtration theory and the Kozeny-Carman equation. It was shown that the proposed method was useful for predicting the separation efficiency of oil droplets and the pressure drop for the separation of oil/water emulsion by granular beds.
View full abstract
-
Keisuke Fukui, Masahiro Fujiwara
1996 Volume 22 Issue 4 Pages
861-866
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The laminar longitudinal vortex rolls driven by the gravity currents between horizontal parallel plates where temperature were not uniform in the lateral direction normal to the forced flow have been investigated by means of a flowvisualization technique and 3-D numerical calculation. The difference in magnitude of gravity currents along the horizontal plates was found to cause three different kinds of vortex rolls. The mechanism of the vortex-roll formation and its effects on the local Nusselt number were made clear from the numerical prediction.
View full abstract
-
Haruhiko Matsuo, Chunhua Luo, Shigeyuki Uemiya, Toshinori Kojima
1996 Volume 22 Issue 4 Pages
867-874
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Solid fraction distribution in a cyrindrical jetting fluidized bed with a center nozzle was measured with an optical fiber probe. The effects of air flow rate through the nozzle, shape of distributor and background air through the distributor on various phenomena were investigated. When a cone shaped distributor was used, jet height, defined as the height from where the solid fraction of the center became a certain value, increased with increasing air flow rate through the nozzle, and its value was close to that estimated by Yang and Keairns' correlation (1979). When a flat distributor was employed, the solid fraction in the jet was higher and the diameter of the jet was larger, but jet height was lower than that when the cone shaped distributor was employed. In the case without background air, a high concentration region was observed in the annulus, and both the jet height and jet diameter became larger, but solid fraction became lower in the jet.
View full abstract
-
Tooru Ishikawa, Singo Ohnuma, Tamotu Kamiya
1996 Volume 22 Issue 4 Pages
875-881
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The transitional process of flow and heat-transfer in a circular pipe fitted with a short static mixer was studied with Newtonian and pseudo-plastic fluids.
An experimental formula, which was derived from the same concept as a well-known transition model of boundary layer flow on a flat plate, coincided well with experimental results of friction and heat-transfer.
The transitional Reynolds number in heat-transfer was larger than that in flow for both fluids.
In heat-transfer experiments, the transitional Reynolds number for a pseudo-plastic fluid was smaller than that for a Newtonian fluid, and heat-transfer augmentation in the transitional region was larger in a pseudo-plastic fluid than in a Newtonian fluid.
View full abstract
-
Kazumi Yamamoto, Meguru Kaminoyama, Kazuhiko Nishi, Mitsuo Kamiwano
1996 Volume 22 Issue 4 Pages
882-890
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
In polymerization inrolving a rapid exothermic reaction, it is necessary for the generated heat in this operation to be removed from the reactor by a cooling coil or jacket to control the reaction temperature. But, fluid in the reactor is gets stagnant as the reaction proceeds, because the viscosity is increasing due to monomer conversion, therefore the reactor often has induced uneven temperature distribution.
In this work, radical addition polymerization was carried out in a reactor using several types of impeller-paddle, anchor, helical screw and helical ribbon, Under these conditions, local temperature distribution was measured in detail using our prototype real-time and multi-point temperature measuring instrument which is able to measure simultaneously changing temperature at local positions via many thermocouples. As a result of these experiments the condition of changing local temperature and the obtained polymers were found to be related to the type of impellers. We found the high temperature areas in the reactor produced polymers composed of undesirably short chain length molecules.
As the cooling condition of the reactor was found by measuring local temperature, we could also find a suitable position for the control sensor of temperature for lowering local higher temperature in the polymerization under the set value.
View full abstract
-
Teruyuki Masawaki, Kazuhisa Tobo, Masahito Taya, Setsuji Tone
1996 Volume 22 Issue 4 Pages
891-897
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Enzymatic hydrolyses of anthraquinone glycosides (Alizarin-2-ο-primeveroside (Al-P) and Lucidin-3-ο-primeveroside (Lu-P)) from madder plant were examined for the formation and separation of the useful pigment, alizarin. Among enzymes tested in this study, almond-derived β-glucosidase showed the highest hydrolytic activity and reaction selectivity for Al-P. Hydrolyses of anthraquinone glycosides were carried out in a batch operation by using the β-glucosidase immobilized by covalent linkage to fine powders of TiO
2, and it was found that the formed alizarin exerted an inhibitory effect on the enzyme reaction.
Separation and recovery of alizarin in a hexane phase were performed by combining solvent extraction with enzyme reaction, reducing the inhibitory effect on the reaction caused by alizarin. Taking into account the partition equilibrium between the aqueous and hexane phases, time profiles of the formation and extraction processes of alizarin were successfully expressed in a batch operation by a Michaelis-Menten equation considering the product inhibition.
View full abstract
-
Masashi Nishizawa, Takayuki Morito, Makoto Matsuura, Hideyuki Aoki, Ta ...
1996 Volume 22 Issue 4 Pages
898-906
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Steam outflow rate and temperature distribution in packed bed of coal particles were measured, measured and compared with results of the numerical analysis in order to determine the steam flow behavior in the coke oven chamber. The moisture controlled and size graded pulverized coal particles are packed in the cylindrical stainless steel vessel with steam flow pipes on both ends. The upper end of the vessel is heated from 293 to 653 K with a constant heating rate of 3 K/min and kept at 653 K. Numerical analysis, including a concept in the evaporation/condensation behavior, is conducted in the axisymmetrical coordinate system. The unsteady heat conduction equation in the solid phase and mass, momentum and energy conservation equations in the gas phase are simultaneously solved. The condensed water in the bed is supposed to be static and as a part of the solid phase under the assumption of local thermal equilibrium. Estimated results on the temperature distribution and the steam outflow rate are quantitatively in good ageement with experimental results and the model performance is verified. Steam flow toward the heated side decreases the heat transfer rate, while steam flow toward the insulated side increases it.
View full abstract
-
Tohru Nagasako, Manabu Shimada, Kikuo Okuyama
1996 Volume 22 Issue 4 Pages
907-915
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The effects of nonuniformity of temperature, physical properties and polymer conversion on the polymerization process in a laminar flow reactor are studied. In the experiments, conversion and average molecular weight of styrene are measured at the outlet of a tubular reactor with heated walls. To theoretically investigate the measured results, the governing equations for momentum, heat and mass transfer with polymerization reaction terms are solved numerically, considering the dependence of the physical properties of the mixture of monomer and polymer on temperature and conversion as well as consumption of monomer and heat generation by the reaction. The calculations show that significant change in the mixture viscosity near the reactor walls due to polymerization causes change in the flow velocity distribution in the reactor. The calculated conversions and average molecular weights agree well with the measured results when the flow velocity of the mixture in the reactor is relatively large. When the flow is slow, however, different conversions are observed between the mixtures flowing upward and downward in the vertical reactor. Temporal change in measured conversion suggests that the difference is caused by gravitational sedimentation of polymer in the reactor.
View full abstract
-
Hidehiko Noda, Yoshihide Nagafuchi, Atsushi Tsukada, Osamu Miyatake
1996 Volume 22 Issue 4 Pages
916-922
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The maximum capillary pressure of a screen wick is one of the most important factors to predict the heat transfer limit of the heat pipe in which a screen wick is installed. An analytical study on the geometry of the menisci formed in the space between the screen layers is conducted to define the effect of wick thickness on the maximum capillary pressure of a screen wick. An experimental study is also conducted to confirm the effect of wick thickness on the maximum capillary pressure using 8 kinds of a screen. The results show that the maximum capillary pressure of the screen wick increases with the decrease of wick thickness and the value reaches almost twice that of a case of a single layer screen. From the correlation between the analytical and the experimental results, a semi-empirical equation for predicting the maximum capillary pressure of the screen wick from the geometry of the screen, contact angle and the wick thickness is derived.
View full abstract
-
Masahiro Goto, Fumiyuki Nakashio, Michio Iwama, Hidekazu Yohizawa, Kaz ...
1996 Volume 22 Issue 4 Pages
923-926
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
A double layer microcapsule composed of nylon and polystyrene has been prepared by a combined process of interfacial polymerization and solvent evaporation. The release rate of sodium ions as a core material was investigated with the microcapsules coated by a synthesized lipid. The permeation rate drastically changed corresponding to the phase transition temperature of the bilayer membranes composed of the lipid. The permeability of the core material above the phase transition temperature was 1-order of magnitude higher than that below the temperature. A functional microcapsule in which a core material is controlled by a membrane structure can be prepared by coating the microcapsule with a synthesized lipid.
View full abstract
-
Mutsuhiro Ito, Fujio Watanabe, Masanobu Hasatani
1996 Volume 22 Issue 4 Pages
926-929
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Heat and mass transfer characteristics in an adsorption heat pump (AHP) using a direct heat exchange module (DS-module) of silica gel were experimentally studied on the basis of results compared with those for the AHP with a multiple adsorbent-tube (MAT) type adsorber. Ultimate heat transfer enhancement for an adsorber of the AHP was almost achieved by using the DS-module and the possibility of its application to a refrigerator for producing low temperature cold heat energy was suggested.
View full abstract
-
Chiaki Hatanaka, Toshihide Haraguchi, Shunsuke Ide, Muneharu Goto, Mas ...
1996 Volume 22 Issue 4 Pages
930-934
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Enzymatic esterification reaction of erythritol and oleic acid was carried out in the reaction system of controlled water content. A higher conversion was obtained when the water content in the system was adjusted ranging from 1, 000 to 4, 000 ppm. It was shown that the water in such systems was bound to the enzyme protein and needed for appearance of the enzyme activity. The process of crystallization of erythritol appeared to be effective for the acceleration of lipase-catalyzed synthesis.
View full abstract
-
Ryuichi Moriyama
1996 Volume 22 Issue 4 Pages
934-937
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
This paper outlines an approach to reduce the pulsating wall pressure near the transition point in a bin which is generated during discharge of a dense bed achieved by peripheral feeding. The author presents a method of controlling the flow of the dense bed by means of a ring installed in the wall near the bin transition point, thus changing the flow from a dense bed to a coarse bed.
View full abstract
-
Liquefaction of Potato Starch in Lactic Acid Solution
Mikio Morita, Yuji Yokota
1996 Volume 22 Issue 4 Pages
938-940
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The liquefaction of potato starch, catalyzed by lactic acid produced in a fermentation process, was carried out as a means for pretreating lactic acid fermentation feed. Liquefaction yield and molecular weight distribution of liquefied starch fractions were largely dependent on pH values of solution. The feed was effectively liquefied in lactic acid solution, of which pH value was less than 3.5, under sterilization conditions of 388 K and 30 min. Starch in potato or its waste was also hydrolyzed into smaller molecular weight fractions, compared to soluble starch commercially available. The potato starch liquefaction proposed is considered to be a useful method for pretreatment of lactic acid fermentation feed.
View full abstract
-
Issei Fujiyoshi
1996 Volume 22 Issue 4 Pages
940-945
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The adsorption experiment of ethylendiamine (en) on porous glass showed selective adsorption of divalent en ion, yielded on apparent adsorption equilibrium constant of 1.00 × 10
-8 kg· m
-3 and on effective amount of acid acting on en ion on porous glass of 0.506 mol· kg
-1 at 298 K. The adsorption experiment of en· nickel complex ion on porous glass yielded an apparent adsorption equilibrium constant of 1.77 × 10
-13 kg· mol· m
-6 and an effective amount of acid acting on nickel complex ion on porous glass of 1.14 mol· kg
-1. For adsorption of en ion, the experimental amount in the en-nickel system agreed with amount estimated by the equation obtained in the en system, and there was no appreciable interaction between the two components adsorbed.
View full abstract
-
Hitoshi Takase, Kazuhiko Sanami
1996 Volume 22 Issue 4 Pages
945-948
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The power consumption characteristics of an agitating impeller in a uniform suspension, in which coarse particles with the same density as that of the liquid were suspended, were investigated. Power consumption was measured under various conditions : particle size distribution of suspended particles ; volume fraction of particles in suspension ; and impeller speed.
It was found that power number increased with increasing mean diameter of particles and volume fraction of particles in suspension, while power number decreased with increasing packing fraction of particles. In the range of Reynolds number
NRe, 6.43 × 10
4 ≤
NRe ≤ 1.07 × 10
5, the power number did not change with
NRe. The empirical formula, which shows the relationship between power number and suspending condition of particles, was obtained.
View full abstract
-
Jianzhong Wang, Akiyoshi Sakoda, Motoyuki Suzuki
1996 Volume 22 Issue 4 Pages
948-952
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The moment analysis of pulse responses was applied to a biological activated carbon (BAC) bed to evaluate the microbial activity. Glucose and activated carbon fiber (ACF) were employed in experiments as a model tracer and an activated carbon respectively. No significant difference in biodegradation rates of glucose by microorganisms attached on different solid supports such as activated carbon, unactivated carbon and glass fibers was observed. However, higher microbial activity was obtained from microorganisms supported on the ACF in terms of the apparent degradation of total organics including metabolic byproducts by microorganisms, since part of the metabolic byproducts was irreversibly deposited onto the ACF.
View full abstract
-
Junji Suzuki, Yoshio Yonei, Chiaki Yokoyama
1996 Volume 22 Issue 4 Pages
953-956
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The composition of three principal components in the extract obtained from tobacco with high pressure CO
2 was simulated. In the calculation of solubility, Chrastil's equation was used. The parameters for solubility of the principal components were calculated using the results of the batch extraction (
SF ratio = 5), in which components were considered to be in equilibrium. For simulation, the extractable limit was set as the calculation condition for neophytadiene. The simulation results for the batch extraction agreed with the experimental results. Furthermore, considering that the semi-batch extractor was equivalent to a series of batch cells, the compositions of the principal components could be also calculated satisfactorily.
View full abstract
-
Toshiyuki Teshiba, Masaharu Takao, Satoru Komori, Yasuhiro Murakami, H ...
1996 Volume 22 Issue 4 Pages
957-959
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The effect of filled ratio on flow characteristics of grinding media was investigated for a horizontal type sand mill, in which the internal blade and external cylinder counter rotated independently. The relationship between flow characteristics and grinding performance was discussed by carring out grinding tests of calcium carbonate. As a result, it was found that the grinding characteristics obtained for both rotation methods can be well correlated as a function of intensity of velocity fluctuations weighted by appearance frequency and the second power of filled ratio, where the reciprocal collision probability of media particles is taken into consideration.
View full abstract
-
Shigetoshi Kobuchi, Shuichi Yamamoto, Yasuhiko Arai
1996 Volume 22 Issue 4 Pages
960-962
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Mutual diffusion coefficients of acryl adhesiveacetate ester (methyl acetate, ethyl acetate, n-propyl acetate) systems were measured at 313.15 K using a sorption-desorption apparatus with a quartz spring. Further, those of an acryl adhesive-ethyl acetate system at 333.15 K were also measured. The concentration range of solute measured was from 0.0127 to 0.159 in mass fraction. Mutual diffusion coefficients obtained depended on concentration, temperature and molecular weight.
View full abstract
-
Toyozo Hamada, Shuji Nakatsuka, Teruyuki Masawaki, Masahito Taya, Sets ...
1996 Volume 22 Issue 4 Pages
962-965
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The effects of the kinds of organic solvents and mole fractions of organic solvents on selective dissolution factors of water to organic solvents were examined by sorption experiment using a polyion complex pervaporation membrane in various binary mixtures of solvent and water. Selective dissolution factors of water to organic solvent increased with increasing mole fractions of organic solvents in the solutions, and the factors also increased with an increase in the difference of Hansen solubility parameter of organic solvent from that of water.
View full abstract
-
Ryoji Takahashi, Shintaro Mitsui, Masafumi Mochizuki, Takashi Akehata
1996 Volume 22 Issue 4 Pages
966-968
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
The effect of amount of sand on gasification performance, such as lower heat value of product gas and amounts of oil and char formed, was studied by using a reactor of 57.5 mm diameter and 600 mm length. In this partial combustion gasification, a smaller degree of partial combustion is desirable for better utilization of heat of combustion. Such partial combustion was realized with relatively large amounts of sand. By considering this fact, and the observed behavior of the lean phase fluidized bed in a cold model experiment, an incipient bed height/column diameter ratio of 1.2 to 1.7 may be advisable for better gasification performance.
View full abstract
-
Katsuyasu Sugawara, Ken-ichi Fukase, Takuo Sugawara
1996 Volume 22 Issue 4 Pages
969-972
Published: July 10, 1996
Released on J-STAGE: November 12, 2009
JOURNAL
FREE ACCESS
Particles of carbon-coated-iron ore were prepared by heating of a mixture of iron ore and phenolphthalein at 773 K in a nitrogen stream. Reduction behavior of iron ore and carbon-coated-iron ore particles during rapid heating has been observed by using a drop-tube reactor in a nitrogen stream at temperatures from 1, 340 to 1, 860 K. The reduction rate of the carbon-coated-iron ore rapidly increased with the beginning of melting and coexistence of metallic iron with bivalent and trivalent iron during heat treatment over 1, 650 K. A fraction of 53% of total iron in iron ore was reduced to metallic iron within 0.5 s by rapid heating at 1, 860 K.
View full abstract
