Editor-in-Chief
Takao Tsukada (Tohoku University)

Associate (Editor-in-Cheifs)
Manabu Shimada (Hiroshima University)
Masahiro Shishido (Yamagata University)

Editors
Ryuichi Egashira (Tokyo Institute of Technology)
Jun Fukai (Kyushu University)
Choji Fukuhara (Shizuoka University)
Toshitaka Funazukuri (Chuo University)
Takayuki Hirai (Osaka University)
Jun-ichi Horiuchi (Kitami Institute of Technology)
Eiji Iritani (Nagoya University)
Yoshinori Itaya (Gifu University)
Noriho Kamiya (Kyushu University)
In-Beum Lee (Pohang University of Science and Technology (POSTEC))
Kouji Maeda (University of Hyogo)
Hideyuki Matsumoto (Tokyo Institute of Technology)
Nobuyoshi Nakagawa (Gunma University)
Masaru Noda (Fukuoka University)
Hiroyasu Ogino (Osaka Prefecture University)
Mitsuhiro Ohta (The University of Tokushima)
Eika W. Qian (Tokyo University of Agriculture and Technology)
Yuji Sakai (Kogakuin University)
Noriaki Sano (Kyoto University)
Naomi Shibasaki-Kitakawa (Tohoku University)
Ken-Ichiro Sotowa (The University of Tokushima)
Hiroshi Suzuki (Kobe University)
Nobuhide Takahashi (Shinshu University)
Shigeki Takishima (Hiroshima University)
Yoshifumi Tsuge (Kyushu University)
Tomoya Tsuji (Nihon University)
Da-Ming Wang (National Taiwan University)
Takuji Yamamoto (University of Hyogo)
Yoshiyuki Yamashita (Tokyo University of Agriculture and Technology)
Miki Yoshimune (National Institute of Advanced Industrial Science and Technology (AIST))

Editorial office:
The Society of Chemical Engineers, Japan
Kyoritsu Building, 4-6-19, Kohinata, Bunkyo-ku
Tokyo 112-0006, Japan
journal@scej.org

AIMS AND SCOPE:

Journal of Chemical Engineering of Japan, an official publication of the Society of Chemical Engineers, Japan, is dedicated to providing timely original research results in the broad field of chemical engineering ranging from fundamental principles to practical applications. Subject areas of this journal are listed below. Research works presented in the journal are considered to have significant and lasting value in chemical engineering.

Physical Properties and Physical Chemistry
Transport Phenomena and Fluid Engineering
Particle Engineering
Separation Engineering
Thermal Engineering
Chemical Reaction Engineering
Process Systems Engineering and Safety
Biochemical Food and Medical Engineering
Micro and Nano Systems
Materials Engineering and Interfacial Phenomena
Energy
Environment
Engineering Education

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The lateral interaction between flowing fluid and flexible structure in an RT stirred tank with a diameter of 0.58 m was numerically simulated by means of a method coupling Computational Fluid Dynamics (CFD) with Computational Structure Dynamics (CSD). The results show that the characteristics of the shaft bending moment predicted by the coupling simulation, including the dimensionless mean and relative standard deviation, are in good agreement with the experimental data. Analyses of the simulation results show that the trajectory shape of impeller lateral movement depends on the impeller mass imbalance. The dimensionless lateral fluid and structural loads separated from the resulting lateral loads are both associated with the impeller speed and imbalance. Further analysis of the impeller lateral force power spectral density shows that the fluctuations of these forces are characterized by the rather low frequency, speed frequency and blade passing frequency.

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Water-in-diesel oil emulsion fuel has been investigated for use in combustion equipment, because of its better fuel economy and pollution reduction effect. In this study, a spray blend mixing system was applied to prepare water-in-diesel oil emulsion fuel, because this system was able to prepare emulsion on-demand. Therefore, the effects of operating conditions such as HLB, gas flow rate, and volume fraction of water phase on the water droplet size were investigated. The water-in-diesel oil emulsion fuel was prepared using the spray blend mixer, and the water droplet size was about several µm. The water droplet size decreases with increasing gas flow rate or decreasing volume fraction of water phase. In addition, an estimation equation of the average droplet size is proposed.

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Two sizes of anthracite and petroleum coke particles were conveyed in a high-pressure experimental setup using nitrogen. Shear tests were conducted on the experimental materials to study their flowability. Comparisons between the conveying characteristics of anthracite and petroleum coke in the pneumatic conveying system were carried out by evaluating the effects of the fluidizing gas flow rate and total differential pressure on the conveying capacity and conveying stability. The influence of the operating parameters and material properties on the resistance properties were evaluated in both straight pipes (including horizontal, vertical, and inclined pipes) and bended pipes conveying anthracite and petroleum coke. The results show that the resistance properties of the experimental materials are different for straight pipes and bends. For conveying in an inclined pipe, the pressure drop increases with an increase in inclination angle ranging from 30 to 60°. Three individual empirical correlations were proposed for predicting pressure drops through horizontal, vertical, and 45° inclined pipes conveying petroleum coke. A comprehensive correlation for pressure drop prediction in inclined pipes conveying anthracite was developed. The correlation combines the material properties, solid–gas ratio μ, Froude number Fr, and inclination angle θ, and has good agreement with the experimental data. The existence of a critical inclination angle was deduced from the correlation.

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The induced air flotation of oil droplets was performed using a microbubble generator to develop a simple and energy saving method for oil-in-water emulsion separation. The microbubble generator, which consisted of a liquid pump and a special line mixer, was set at the bottom of a bubble column. The effects of operation conditions on the oil separation performance were investigated. A sintered glass gas sparger was also used to disperse millibubbles. Oil-in-water emulsions were prepared from soybean oil and water. Compared with millibubbles, the dispersion of microbubbles effectively separated oil. This was because microbubbles had high efficiency of collision with droplets and it was difficult to detach droplets because of the low rising velocity of microbubbles. Millibubbles were difficult to attach to oil droplets and easy to detach droplets because of the high velocity movement of bubbles. The oil separation ratio was a maximum at the gas velocity of 0.2 mm/s because the amount of millibubbles increased as the gas velocity became higher above 0.4 mm/s. The oil separation was largely enhanced at the solution pH below 4.5. The zeta potential of droplets was negative in the pH range from 3 to 11. However, as the solution pH became lower, the zeta potential of microbubbles changed from negative to positive at the solution pH of 4.5. In addition to the hydrophobic attraction, the electrostatic attraction between oil droplets and microbubbles was generated since the zeta potentials of droplets and microbubbles had negative and positive values, respectively.

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The time, t_C, elapsed from bubble contact to the rupture of the liquid film between two bubbles in a quasi two-dimensional column was measured to investigate the effects of the particle diameter on bubble coalescence. The particle diameter ranged from 60 to 150 µm and the particle volumetric concentration ranged from 0 to 0.50 (50%). The effects of particle diameter on bubble coalescence were evaluated through the experiments and were implemented into a bubble coalescence model for a multi-fluid model. Distributions of the gas holdup in a three-dimensional slurry bubble column were also measured using an electrical conductivity probe to obtain experimental data for validation of the coalescence model. The conclusions obtained are as follows: (1) t_C decreases, in other words, bubble coalescence is enhanced with decreasing the particle diameter, which results in the reduction of the gas holdup of the slurry bubble column, (2) the particle-effect multiplier to t_C is of great use to take into account the effects of the particle concentration and diameter in multi-fluid simulations of slurry bubble columns, and (3) the interaction between the bubble interfaces and particles in the bubble coalescence process after bubble contact is a local phenomenon and rarely depends on the macroscopic behavior of the interface, which allows us to develop a correlation for particle-induced enhancement of bubble coalescence for three-dimensional bubble columns even with a small experimental setup like a Hele–Shaw cell.

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Though the amount of brown coal resources in the world is abundant, and its moisture content is often high (more than 30%, wet basis). Thus, fluidized bed drying systems, using superheated steam for fluidizing gas, has been developed as a large capacity and low energy consumption drying technology. Brown coal particles used in fluidized beds are classified into B particles according to Geldart’s classification. However, particle properties, size, density and cohesiveness change with moisture content. Therefore, it is important to know the influence of moisture content on its fluidization characteristics. In this work, experiments were carried out to evaluate the effect of moisture content and particle size distribution on fluidization characteristics by using a fluidized bed cold model. For fluidization characteristics, minimum fluidization velocity, minimum complete fluidization velocity and minimum complete mixing velocity were measured. As a result, a quantitative relationship between the particle size distribution and fluidization characteristics was obtained. Also, a quantitative relationship between moisture content and fluidization characteristics was obtained by introducing an angle of repose as an index of cohesiveness.

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A novel polymeric ionic liquid (PIL) gel was synthesized via radical polymerization of the ionic liquid monomers, 1-vinyl-3-ethylimidazoliumbis(trifluorometyl-sulfonyl) imide ([veim][Tf₂N]). The gel was made porous by removing the water phase dispersed by polyoxyethylene (20) sorbitan monolaurate (Tween-20). The porous structure of the synthesized gel was observed by SEM imaging. In comparison to the nonporous PIL gel synthesized without Tween-20, the adsorption capacity of Au(III) onto porous PIL gel was enhanced. The adsorption behavior of the synthesized gel was studied in acidic chloride solutions containing various metal ions, and it was found that the gel selectively adsorbed Au(III) over other metal ions. Maximum adsorption capacity of Au(III) was more than 140 mg/g; whereas, those for Pt(IV) and Pd(II) were lower than 20 mg/g. The adsorbed Au(III) onto the gel can easily be desorbed using an acidified thiourea aqueous solution. The feasibility of utilizing the polymeric ionic liquid gel for the separation of Au(III) was thereby demonstrated.

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The adsorption and desorption breakthrough test of hydrogen chloride (HCl) was performed by loading zeolite 13X pellet (molecular sieve 13X, Aldrich Co., U.S.A.), a commercial adsorbent, onto a fixed bed reactor (height 15 cm, inside diameter 0.5 cm). The breakthrough test was carried out by changing various experimental conditions such as inlet flow rate (0.5, 1, 1.5, 2 L/min), HCl concentration (200, 350, 500, 650 ppm), reaction temperature (30, 50, 70, 90°C), and reaction pressure (1, 5, 10, 15, 20 bar) with considering the retention time and space velocity. After evaluating the adsorption and the desorption characteristics of HCl on the MS-13X, the consecutive cyclic test (5 times of adsorption step, 4 times of desorption step) was carried out with optimum condition. At the adsorption step, pressure was 20 bar, temperature was 30°C, HCl concentration was 200 ppm, total inlet flow rate was 0.5 L/min (HCl+N₂). At the desorption step, pressure was 1 bar (atmospheric pressure), temperature was 280°C, total inlet flow rate was 0.5 L/min (N₂ only), desorption time (regeneration time) was 7 h. The optical, physical, and chemical characteristics of MS-13X were analyzed using BET, XRD, SEM, EDX, and TGA before and after breakthrough tests.

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In the field of separation, a fusible filter has the following advantages: 1) materials captured by the filter can be recovered by melting the filter, 2) the filter can be recycled, and 3) the latent heat of solidification required to produce the filter is significantly lower than that of vaporization. Herein, we report on the removal of stable surfactants (e.g., proteins) from surfactant-coated emulsified oil droplets via centrifugal filtration using a fusible filter.

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We have earlier showed how the catalytic conversion of 1,2-propandiol to propanal using FSM-16 (#16 folded sheets of mesoporous materials) when molded by wet treatment proceeded more favorably than when using FSM-16 molded by pressurization, while no comparison using other typical acidic catalysts and no examination of the acidic properties of FSM-16 was carried out. In the present study, the conversion using FSM-16 molded by wet treatment and pressurization was compared with that obtained by using typical acidic catalysts such as SiW₁₂O₄₀/SiO₂ and MCM-41 (#41 of Mobil Composition of Matter) together with amorphous SiO₂. Among these catalysts, FSM-16 molded by wet treatment showed the most suitable catalytic activity. In order to examine the effect of the molding procedure for FSM-16 on its structural and acidic properties, FSM-16 molded by both methods was examined using NH₃-TPD, in situ FT-IR using NH₃ as a probe molecule, and Hammett indicators together with XRD and TEM. According to Zaitsev’s rule, the present conversion should afford acetone rather than propanal, which indicates that it would proceed via hydro cracking. Therefore, the conversion of 1,2-propandiol using FSM-16 was also examined in the presence and absence of hydrogen. Furthermore, hydration reactions of 1- and 2-propanol when using FMS-16 were examined. Based on the results obtained from this investigation, it was concluded that the conversion using a more acidic FSM-16 molded by wet treatment proceeded through dehydration rather than through hydro cracking.

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A systematic procedure is proposed for designing an internally heat integrated distillation column which separates a binary mixture. In the proposed procedure, the liquid compositions in the column are discretized and each of them is assigned to a stage in a column. The feature of the proposed procedure is that the structure of vapor and liquid paths among the stages are treated as design variables. The combinations of the heat exchange stages in the stripping and rectifying sections are also treated as design variables. As the liquid composition of each stage has been decided in advance, the state variables related to each stage can be calculated before solving the synthesis problem. Thus, the design problem is formulated as a mixed integer linear programming problem, and the optimal column structure is derived by solving it. The proposed method was applied to the problems of separating a benzene-toluene mixture. The results show that the structure of an internally heat-integrated distillation column is systematically derived. Furthermore, an unexpected innovative structure called a stepwise condenser was generated by the proposed procedure.

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As a typical locally recurrent network, the Elman neural network is widely used in nonlinear dynamic modeling and real-time control of nonlinear systems because of its dynamic performance. The structure of the Elman neural network, which is generally determined based on user experience or trial and error, plays an important role in the network’s prediction performance. Establishing a simple and optimal structure remains a problematic issue. In order to overcome this problem, the pruning Levenberg–Marquardt (PLM) training method, in which sensitivity pruning is added into its training process to obtain the optimal structure, is proposed. In the PLM method, the training process starts with an oversized structure, then the redundant hidden and context neurons are pruned and the configuration parameters are adjusted by mainly using the LM algorithm. In one pruning operation, the hidden neuron and corresponding context neuron with the least sensitivity are removed. The pruning interval, which is adaptive based on training error, is used to evaluate the success of the last pruning step and the finish of training. Further, a multi-input multi-output Elman neural network model trained by PLM method is employed for a fed-batch penicillin fermentation process. The satisfactory results indicate that the Elman model with sensitivity pruning has an appropriate structure size and performs better than the models without pruning.

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Submicron particles comprising nanocrystallites of Gd_0.1Ce_0.9O_1.95 (GDC), NiO–Gd_0.1Ce_0.9O_1.95 (NiO–GDC), and La_0.8Sr_0.2CoO₃ (LSC) were synthesized using ultrasonic spray pyrolysis in a reactor at 1,273 K for 13 s. Nitrates of the component metals were used as precursors and dissolved in pure water in stoichiometric amounts of GDC, NiO–GDC, and LSC. GDC and NiO–GDC were spherical, whereas LSC were nonspherical. The crystalline nature of GDC improved on increasing the reactor temperature from 773 to 1,273 K during the reaction time of 13 s. The average sizes of NiO–GDC and LSC crystallites prepared using the solution concentration of 0.2 mol L⁻¹ were bigger than those prepared using 0.02 mol L⁻¹ solutions.

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Nitrogen-containing ordered mesoporous carbon films were synthesized using m-aminophenol as a single carbon and nitrogen source with triblock copolymer Pluronic F127 as a template. First, an m-aminophenol/F127 composite with an ordered mesostructure was formed on a silicon substrate. Successive infiltration of formaldehyde vapor caused copolymerization of m-aminophenol and formaldehyde thereby growing slowly with its ordered mesostructure. This method can form a self-assembly carbon source and triblock copolymer, which cannot be formed by conventional sol–gel methods due to their rapid polymerization of the carbon source. X-ray diffraction patterns and transmission electron microscope observation suggests that the carbon film is composed of some domains which are randomly oriented. The X-ray photoelectron spectroscopy indicates that the carbon film contains large percentages of pyridinic and graphitic nitrogen atoms. Cyclic voltammograms are nearly rectangular in shape, which is ideal for electrochemical double layer capacitors. Additionally, the carbon film exhibits small and broad peaks, indicating that pseudocapacitive reactions occurred on the interior surface due to doping of the nitrogen atoms into the carbon.

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