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Toshiro Murase, Eiji Iritani, P. Chidphong, Kazuhiko Yagishita, Kazuma ...
1988 Volume 14 Issue 2 Pages
135-140
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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High filtration rate can be achieved by limiting cake growth in a dynamic filter. Dynamic filtration, which only allows the formation of ultra-thin cake, is accomplished by use of vibrating plates moving parallel to the cake surface. Effects of the vibration parameters on filtration performance are studied under vacuum, constantpressure conditions. Three types of vibrating plates are employed : a flat plate, a plate with grooves and a plate with protrusions, each maintained at a small clearance from the filter medium. The filter cake is continuously swept from the medium surface by the shearing action of liquid flow generated by vibrating the plate. It is shown that the thin cake allows a much higher filtration rate in vibratory filtration than that in conventional cake filtration. It is also demonstrated that the vibratory filtration rate depends mainly on the maximum velocity of the vibrating plate. A method is developed for evaluating the variations of filtrate volume with time by introducing an empirical correction factor, called a vibratory filtration rate factor, into the Ruth filtration rate equation.
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Takeo Shiojima, Hiroaki Endoh, Shigeru Matsumoto
1988 Volume 14 Issue 2 Pages
141-146
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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Numerical simulations are carried out to analyze the operation performance of an aromatization reactor in a commercial catalytic reforming process. The model employed consists of 57 elementary reactions and 33 chemical species and also takes into account temperature changes in the reactor during the reaction. It is demonstrated that the simulation results are in fairly good agreement with mesurements of commericial runs runs in terms of distribution (yield pattern) of products and temperature drop.
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Masatoshi Yoshida, Shigeru Matsumoto, Goushi Honda, Tsutomu Iwama, Yas ...
1988 Volume 14 Issue 2 Pages
147-154
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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The control scheme recently proposed by the authors is applied to the control of axial temperature distribution in a bench-scale supercritical-gas extractor. The extraction unit is constructed from a packed column of 3 m length covered by a coaxial cylindrical casing. Although the actual structure of the extractor is very complicated, it is modeled by a simple double-pipe and therefore its mathematical model becomes a pair of partial differential equations. The models are reduced to lumped parameter systems with a finite dimension by use of the finite Fourier transform technique. The controller is designed on the basis of the reduced model. Extended Kalman filter is used to estimate simultaneously the state variables and unknown parameters. The results demonstrate that both the state estimation and the controller performance are satisfactory. This implies that the control scheme is very robust in spite of the incompleteness of the model used.
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Hayami Ito, Shuhei Tatsumi, Yoshihiro Kajibata, Shoichi Takao, Hironor ...
1988 Volume 14 Issue 2 Pages
155-160
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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The wet grinding characteristics of CWM (Coal Water Mixture) at high concentrations was investigated by conducting batch preparation tests using a laboratory-scale ball mill.
Although the grindability became worse with the increase of slurry concentration, it was found possible to prepare CWM of 65 to 75% by use of the proper dispersant. The improvement of grindability was caused by the improved movement of balls owing to the decrease of apparent viscosity at low shear rates. The grindability greatly changed with coal type. The difference of grindability among coal types was mainly due to the difference of flocculation force.
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Hidemitsu Hojo, Ken Tsuda, Katsuyuki Shirato, Tomohiko Yabu
1988 Volume 14 Issue 2 Pages
161-166
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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Slurry erosion of polystyrene were studied by a jet apparatus, and erosion behavior was investigated by considering the effect of flow on the impact behavior of slurry particles on the specimen.
Erosion rate differed greatly at different positions on the specimen, due to differences in impact velocity and angle of the slurry particles.
When the slurry jet impacted a specimen set perpendicular to the jet axis, assuming stagnation flow, the distribution of impact velocity, angle and striking efficiency could be numerically calculated.
The distribution of specimen erosion depth was estimated on the basis of calculation, and these results agreed approximately with experimental results.
It was concluded that an understanding of the effect of fluid flow on the behavior of slurry particles is important to make clear the slurry erosion damage.
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Koji Hiyoshi, Masanari Fujiwara, Kazuto Okada, Noriyuki Miyazaki, Tsuy ...
1988 Volume 14 Issue 2 Pages
167-173
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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The present paper deals with the runaway of solid particles having large diameter beyond the separable limit through blades in a louver-type dust separator. The following results were obtained from particle collection experiments using a two-sided louver. (1) For larger particles, the particle collection efficiency decreases with increasing inlet air velocity, and more particles run away through the blades set on the blowdown approach. (2) A center plate inserted in the louver helps prevent large particles from running away through the blades.
The following points are inferred from the particle trajectories obtained from a numerical simulation of large particles. (1) The particle motion vertical to inlet air is amplified by impinging on blades, with increasing inlet air velocity. Its motion promotes the runaway of particles through blades. (2) A center plate inserted in the louver suppresses the runaway of particles through blades due to the inelastic collision of particles against the plate.
It was experimentally verified by measuring the collision frequency against the bottom wall of a one-sided louver that the particle motion vertical to inlet air increases with increasing inlet air veloity.
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Tadaatsu Ido, Yuuki Matsuura, Shigeo Goto
1988 Volume 14 Issue 2 Pages
174-181
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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The dehydrohalogenation of 2-bromooctane in toluene (organic phase) by trioctylmethylammonium chloride (phase transfer catalyst) was investigated in a batch reactor containing an aqueous solution of potassium hydroxide (aqueous phase). Reaction rates varied significantly with the start-up procedure, that is, the method of mixing of aqueous phase and catalyst. To clarify these strange phenomena, the base strength and the base efficiency (moles of base per mole of catalyst) of catalyst in organic phase were measured by titration of the catalyst with benzoic acid, using acid indicators. The base strength and the basicity of the catalyst varied with operating conditions. In some cases, the catalyst had the character of a super-strong base. Under other conditions, only a small part of the catalyst had basic character and the base efficiency in organic phase decreased with time. This decrease, however, was prevented by the addition of methanol. The reaction rate of dehydrohalogenation was proportional to the base concentration of the catalyst in organic phase.
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Yoshiyuki Bando, Michio Kuraishi, Makoto Nishimura, Seiji Ando, Makoto ...
1988 Volume 14 Issue 2 Pages
182-188
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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Bubble columns of 5000 mm height and seven diameters (50, 70, 94, 114, 164, 200 and 280mm) were employed for visual observations of flow patterns and measurements of gas holdup and gas-liquid interfacial areas, under gas and liquid flow conditions covering the ranges of cocurrent upflow, countercurrent flow and cocurrent downflow. Air was used as gas and tap water and sodium sulfate solution were used as liquid medium. Gas-liquid interfacial areas were determined by using sodium sulfite oxidation reaction.
When column diameter or liquid species was changed, flow pattern transition occurred at different gas and liquid velocities, and the transitions were judged by gas-liquid slip velocities. Experimental correlations of gas holdup were derived for bubble flow and churn turbulent flow. In every gas-liquid flow mode, no effect of column diameter on gas holdup was observed beyond 140 mm column diameter. Gas-liquid interfacial areas strongly depended on gas holdup, and this dependency in bubble flow regime was different from that in churn turbulent flow regime.
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Teruo Takahashi, Zennosuke Tanaka, Satoru Kaseno
1988 Volume 14 Issue 2 Pages
189-194
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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The power requirement in the gas-solid stirred fluidized bed is greatly affected by the shape and size of the stirrer. In this work, power requirement and pressure drop of gas through the bed were studied using fluidized bed columns of 0.15 m and 0.3 m diameter with 10 types of vertical blades and 5 kinds of powder.
It was found that the required torque for stirring the bed in the range of high gas velocity was constant. Such minimum torque for stirring was affected by rotational speed, size of the stirrer, chracteristics of powder used and its total inventory. The effect of stirrer size on the minimum torque could be explained by a bed core rotating model. An empirical equation of the minimum torque was proposed.
In the region of fixed bed the pressure drop of gas through the bed was reduced because the void of powder was increased by stirring.
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Eiji Harada, Masafumi Kuriyama, Hirotaka Konno
1988 Volume 14 Issue 2 Pages
195-202
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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Heat transfer measurements were made for glass beads-water suspensions flowing through a horizontal rectangular duct whose upper and lower plates were heated and the mechanism of heat transfer between wall and suspensions was studied.
In the heterogeneous flow region, the heat transfer coefficients were the same for upper and lower plates and were always larger than that of water flow. In the region of flow with a stationary bed, on the other hand, the average heat transfer coefficient was affected by both particle size and volume fraction of solid because the thickness of the stationary bed, acting as a resistance against heat transfer from the lower plate of the duct, was also affected by them.
On the basis of the data for velocity and temperature distributions, a simple model was proposed to estimate the average heat transfer coefficient in both the region of flow with a moving bed and that of flow with a stationary bed. The behavior of the heat transfer coefficient determined in this work was elucidated well by the model.
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Toshiyuki Koya, Eiichi Komata, Daizo Kunii
1988 Volume 14 Issue 2 Pages
203-208
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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A process was proposed to for direct reduction of fine iron ore which is pelletized with heavy oil.
To determine the practicality of the above process, two problems related to the fluidized-bed reactor were studied.
(1) Experiments were performed to determine the residence time of a large particle in the fluidized bed by using a cold model.
Conditions for realizing the long residence time of a large particle or piston flow-like residence time were found. Also, an empirical equation for the mean sinking velocity of a large solid was obtained.
(2) A new methed of removing large particles from the fluidized bed was studied.
A screw discharger whose blades have a number of holes was connected to the bottom of the fluidized bed. Consequently, discharge of the large particles without accompanying fine particles could be attained.
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Hiroshi Moritomi, Yuzo Sanada, Tadatoshi Chiba
1988 Volume 14 Issue 2 Pages
209-215
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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A new kinetic model of coal liquefaction, which adds to our previous model an accounting of the hydrogen transfer processes, is utilized for analysis of semi-coke formation and hydrogen transfer from the gas phase to coal and products during liquefaction. All reaction rate constants in the model were determined through a step-wise simulation and comparison with our published date of coal conversion, product yields and hydrogen consumption for Taiheiyo coal liquefaction under a systematic combination of operating conditions such as gas atmosphere, solvent, catalyst and starting materials of the reaction. It is shown from the results that 1) when tetralin is employed as a hydrogen-donor solvent, dihydronaphthalene produced from the tetralin exhibits a hydrogenation activity more than 10 times that of tetralin ; 2) to suppress the semi-coke formation effectively, a sufficient amount of hydrogen-donor solvents should be supplied in the initial stage of liquefaction ; and 3) experimental results of hydrogen consumption in the presence of catalyst are explained much better by assuming the indirect transfer of gaseous hydrogen to coal and products via spent hydrogen-donor or coal-derived solvents rather than direct transfer.
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Kazuyoshi Arai, Yashuhiro Tomita, Ken Tsuda, Hidemitsu Hojo
1988 Volume 14 Issue 2 Pages
216-222
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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Behavior of slurry flow around a wedge-shaped specimen were studied to clarify slurry erosion damage behavior and its mechanism.
Glass beads of 176 μm diameter and water were used as slurry flow, and wedge angles of specimens were varied from 60 to 180°.
Flow behavior of liquid and particles around the specimen were analyzed by numerical calculation, and were also observed experimentally by a chopper method developed by the authors. The analytical results agreed quite well with experimental ones.
Impact velocity, impact angle and striking efficiency obtained from calculations were important factors in erosion damage, and differed greatly at different locations on the specimen. A knowledge of these factors is required to understand erosion behavior properly.
Erosion tests of epoxy resin were carried out, and the effects of impact velocity and impact angle on erosion damage were determined by applying numerical calculation results.
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Hideo Yasui, Wataru Okada, Hisashi Morikawa
1988 Volume 14 Issue 2 Pages
223-229
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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In the seed coagulation method of recovering polymer from latex as spherical particles, the step of particle growth with coagulation, which is regulated by diffusion of coagulant, was studied. By measuring the concentration of each element of coagulant in particles and latex during the step, a model of particle growth was introduced to obtain an equation of growth rate. It was found that the result of numerical calculation on growth corresponded well to experimental data. Thus the growth model is concluded to be applicable and quantitative study of the coagulation of latex has become possible as well.
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Shigeharu Tanisho, Takeshi Shimazaki, Noriaki Wakao
1988 Volume 14 Issue 2 Pages
230-233
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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Resting cells of
E. aerogenes strain E. 82005 evolved hydrogen at a speed of 28 m
l / (g-dry cell.h) from glucose. The evolution rate of the resting cells was stabilized by immobilization with calcium alginate in a wide range of pH from 4.5 to 7.5. Since the rate (ca. 58 m
l/ (g-dry cell. h)) was greater than that of growing cells below pH 5 and above pH 7, hydrogen evolution under these particular conditions could be enhanced by immobilizing the cells.
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Mitsuo Kamiwano, Fumio Saito
1988 Volume 14 Issue 2 Pages
234-237
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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The progressive process of reaction with diffusion of reactants in high-viscosity liquid under simple shear flow was studied. The reaction process is simulated by combining the reaction and diffusion equation with the equation representing the decrease of segregation scale. Reaction experiments were carried out by using a cylindrical vessel with coaxial cylinder. I
2 and Na
2S
2O
3, each dissolved in corn syrup, were chosen as the reaction system. The variation of concentration of each reactant with time and the time until the end point of reaction were found to be in fairly good agreement with those simulated analytically.
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Osamu Miyatake, Itsuo Tanaka
1988 Volume 14 Issue 2 Pages
237-240
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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A simplified dimensionless expression suitable for predicting the growth rate of a vapor bubble in uniformly superheated aqueous solutions of sodium chloride was derived from the results of numerical analysis. The expression is generally valid in both inertia-controlled and heat transfer-controlled growth regions. The derived expression is also found to be in fair agreement with previous experimental results.
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Toshiro Murase, Eiji Iritani, Shuji Nakatsuka, Mompei Shirato
1988 Volume 14 Issue 2 Pages
241-244
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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To investigate the real phenomena of membrane fouling during ultrafiltration, it is essential to visualize the characteristics of the gel layer formed on the membrane surface. Unstirred dead-end ultrafiltration experiments were conducted under constant pressure, using a batchwise filter, newly designed to have a sudden reduction in filtration area. The experimental results of the ultrafiltration rate provided overall filtration characteristics of gelcake, such as cake thickness, average specific filtration resistance, average porosity and ratio of wet to dry cake mass. It was found from the tendency of these characteristic values that the mechanism of batch ultrafiltration could be sufficiently analyzed using the conventional cake filtration theory.
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Kenji Fukuchi, Yasuhiko Arai
1988 Volume 14 Issue 2 Pages
245-249
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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Adsorption equilibria of two solutes (acetone+1-butanol, acetone+phenol, 1-butanol+phenol) and three solutes (acetone+1-butanol+phenol) from dilute aqueous solutions on activated carbon were measured at 25°C. The concentration range of a given solute was up to 100 mmol·dm
-3 while the initial concentration of coexisting components was adjusted to 20 or 40 mmol·dm
-3.
The vacancy solution model proposed in previous work was applied to correlate the present adsorption equilibrium data. It was found that the model can correlate within about 10% for two-solute systems and can predict within about 15% for the three-solute system.
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Hiroaki Yasuoka, Kunio Hirata, Eiji Nakanishi, Eiichi Kunugita
1988 Volume 14 Issue 2 Pages
249-252
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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As shown in the previous paper, a characteristic function MT which is easily calculated at any instant by using the observed values of temperature in the column is useful in determining the optimum switching time from total reflux operation to steady-state operation where the initial composition in each tray is equal in value.
The applicability of the characteristic function defined in the previous paper is examined experimentally for the more realistic start-up of a distillation column with the following steps. 1. Feed is supplied through the feed tray until holdup in each tray in the stripping section is filled up. 2. Total reflux operation is initiated. 3. Reflux is switched from total reflux operation to steady-state operation at appropriate switching time.
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Jiro Koga, Shun-ichi Kudo, Toshitaka Kobayashi, Ichiro Inoue
1988 Volume 14 Issue 2 Pages
252-255
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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The fluidized bed is combined with a spray dryer in milk powder processing in order to improve the thermal efficiency and the properties of powder, such as moisture content, dispersibility and solubility. The purpose of this study was collection of data to design and develop the large-scale equipment.
The holdup, rates of entrainment, agglomeration and drying of powder were investigated under several conditions. The amount of residue in the product powder from the fluidized bed is about one-tenth of that in the feed powder.
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Hiroshi Takahashi, Koji Ando, Takao Takeuchi, Yousuke Maekawa
1988 Volume 14 Issue 2 Pages
256-259
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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The gas holdup characteristics of a continuous annular bubble column of coal were studied. Coalescence of bubbles occurred more readily in the slurry bubble column than in the air-water two-phase bubble column. The gas holdup ε
G decreased with increasing slurry flow rate and solid concentration. However, increase of ε
G with increasing solid concentration was found in a higher range of solid concentration. Considering such an effect related to solid concentration, an empirical correlation for the estimation of gas holdup was derived. The applicability of the previously reported correlations for the slurry bubble column was also studied.
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Satoru Kato, Junjiro Kawasaki
1988 Volume 14 Issue 2 Pages
259-262
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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Controlling factors of batchwise separation of hydrocarbons by liquid membranes were derived from the model proposed previously, which predicts hydrocarbon permeation through liquid emulsion membranes. The range of values for the factors were determined from reported experimental data. The present paper further describes effets of factors and initial operating parameters on the relationship between yield and selectivity in hydrocarbon separation.
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Kohei Ogawa, Chiaki Kuroda, Toshiki Hirose
1988 Volume 14 Issue 2 Pages
262-266
Published: March 10, 1988
Released on J-STAGE: October 21, 2009
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The effect of applied sound wave passed through the bottom of a cylindrical tank, which has a column of small diameter at the inlet in order to originate the Kármán vortex as a known disturbance and through which liquid flows, was investigated experimentally by injecting a tracer stepwise at the inlet of the tank. It was made clear that a low-frequency sound wave having almost the same frequency as that of the Kármán vortex promotes micro mixing, represented by fluctuations having a lower frequency than that of the Kármán vortex.
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1988 Volume 14 Issue 2 Pages
266a
Published: 1988
Released on J-STAGE: October 21, 2009
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1988 Volume 14 Issue 2 Pages
266b
Published: 1988
Released on J-STAGE: October 21, 2009
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1988 Volume 14 Issue 2 Pages
266c
Published: 1988
Released on J-STAGE: October 21, 2009
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