Editor-in-Chief: Yoshiyuki Yamashita (Tokyo University of Agriculture and Technology)
Associate Editors-in-Chiefs:
Hiroyuki Honda (Nagoya University)
Takao Tsukada (Tohoku University)

Editors
Tomohiro Akiyama (Hokkaido University)
Georges Belfort (Rensselaer Polytechnic Institute)
Jun Fukai (Kyushu University)
Yutaka Genchi (National Institute of Advanced Industrial Science and Technology (AIST))
Takayuki Hirai (Osaka University)
Masahiko Hirao (The University of Tokyo)
In-Beum Lee (Pohang University of Science and Technology (POSTEC))
Eiji Iritani (Nagoya University)
Hideo Kameyama (Tokyo University of Agriculture and Technology)
Masahiro Kino-oka (Osaka University)
Toshinori Kojima (Seikei University)
Noriaki Kubota (Iwate University (Professor Emeritus))
Shin Mukai (Hokkaido University)
Akinori Muto (Okayama University)
Nobuyoshi Nakagawa (Gunma University)
Satoru Nishiyama (Kobe University)
Hiroyasu Ogino (Osaka Prefecture University)
Naoto Ohmura (Kobe University)
Mitsuhiro Ohta (Muroran Institute of Technology)
Hiroshi Ooshima (Osaka City University)
Noriaki Sano (Kyoto University)
Manabu Shimada (Hiroshima University)
Masahiro Shishido (Yamagata University)
Shigeki Takishima (Hiroshima University)
Richard Lee Smith, Jr. (Tohoku University)
Yoshifumi Tsuge (Kyushu University)
Da-Ming Wang (National Taiwan University)

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

The Instructions for Contributors and other information are available through our website (http://www.scej.org/jcej/).

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The present study investigated the dispersion of floating particles in a Taylor vortex flow reactor experimentally and numerically. The working fluid was glycerin solution and had a density (ρ_f) of 1210 kg·m^-3 and a viscosity (μ) of 0.1 Pa·s. Floating particles of an acrylic resin had a density (ρ_p) of 1190 kg·m^-3.Two groups of particles with mean diameters of 710 and 974μm were discerned. Although particles penetrated the Taylor vortex flow region in the axial direction at different rotational Reynolds numbers, particle segregation was observed. It was confirmed that the smaller particles penetrated deeper in the axial direction. Numerical simulations were also conducted to elucidate the mechanism of particle segregation. Numerical results of a particle-tracking method indicate that the small particles moved on the outermost orbit of a torus. Results of a distinct element method suggest that interparticle collision affected particle transference between vortices.

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The objective of this study is to propose a scale-up factor for a mean drop diameter in batch rotor.stator mixers. We define a homogenization index (H.I.) as a scale-up factor obtained from a local energy dissipation rate of turbulence and a circulation number. The local energy dissipation rate is calculated using the volume of the homogenization region, and the local power consumption is obtained from the measured net power consumption and the flow rate.We also measure the mean drop diameter using certain time interval for different configurations of mixers and different operating conditions in order to evaluate the validity of the scale-up index using H.I. Experimental results show that H.I. could well account for the mean drop diameter under different rotor speed conditions (13–27 m/s), with a different gap width between the rotor and the stator (0.15–0.25 mm) and different sizes of mixers and production volume (rotor diameters were 30 and 57 mm; production scale was 1.5 and 9 L). These results indicate that H.I. can be used to predict the mean drop diameter. Our results also suggest that the scale-up criteria for the mean drop diameter in relation to mixing time is based on H.I., and not necessarily on geometrical similarities, same rotor tip speed, or gap width in the case of similar mixer configurations and our experimental range (1 to 10 L) used for our model product, which is similar to typical dairy foods.

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A model is proposed for the dynamics of spreading of a liquid drop under the action of capillary forces in the case of partial wetting. Deviation from the spherical cap profile is taken into account. The spreading kinetics is obtained using a dynamic contact angle boundary condition in which the velocity of the contact line is given as a function of the dynamic contact angle and a cut off of molecular size below which the continuum theory breaks down. Results are found to be in very good agreement with published experimental data even at high dynamic contact angles, well beyond the range of applicability of the lubrication theory. Differences between the spreading and dewetting cases are discussed. Further investigation is needed to treat the dewetting case.

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The use of microfluidic devices as analytical tools to probe the kinetics of interfacial reactions between heterogeneous phases such as those that occur in solvent extraction systems can provide important information on the interfacial processes that control these reactions. A number of studies have proposed the use of microfluidic devices for lab-on-a-chip processing. In either case, a detailed understanding of the hydrodynamic and diffusion behavior of the fluids in these devices is essential.
In this study, the diffusion of Co(II) in an aqueous phase and the diffusion of the cobalt(II)-di-(2-ethylhexyl)-phosphate (Co(II)-DEHPA) complex in an organic phase were investigated in a double-Y-type microfluidic device. Diffusion experiments were carried out over a range of flow rates in the laminar flow region of the microfluidic device.
A computational Fluid Dynamics (CFD) simulation of the flow field was carried out and the detailed velocity distribution in the channel was obtained; this distribution was used to predict the rate of diffusion of a solute. Furthermore, a simplified calculation mesh was developed for reducing the simulation time. The diffusion coefficients of Co(II) and the Co(II)-DEHPA complex were determined by the simulation to be 6.6×10⁻¹⁰ m²/s and 3.2×10⁻¹⁰ m²/s, respectively.

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Experimental studies on flow characteristics and particle size distributions of trimethylolethane (TME) hydrate slurries treated with drag-reducing surfactants have been conducted to investigate the effect of the molar ratio of counter-ions to surfactants. Oleylbishydroxyethylmethylammonium chloride is used as the drag-reducing surfactants. The molar ratio of sodium salicylate supplying counter-ions to surfactants is adjusted from 0 to 100 while the concentrations of TME in water and of surfactants remains constant at 25 wt% and at 2000 ppm, respectively. Results unexpectedly indicate that the drag reduction is greatest when the molar ratio of the counterions to surfactants is 20 against the fact that the higher molar ratio shows the higher drag reduction in water case. This indicates that some interaction between the counter-ions and TME molecules occurs and that it disturbs the formation of rod-like micellar structures causing the drag reduction. Thus, a molar ratio of counterions to surfactants of 20 is concluded to be the optimum for the drag reduction although it has a detrimental effect on the particle size under the present experimental conditions used.

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In this study, we propose an evaluation method of a homogenization effect for different stator configurations of internally circulated batch rotor-stator mixers. The homogenization effect has been evaluated indirectly using a homogenization coefficient (C_h) based on the measured power number, estimated flow number, and calculated shear frequency derived from the number of rotor blades and stator holes. In order to estimate the flow number of an internally circulated batch rotor-stator mixer, the flow rate of an externally circulated mixer that had a similar rotor-stator configuration was used. As a result of C_h evaluation by operation with water, it is inferred that the homogenization effect is much higher with a smaller stator hole diameter and a larger number of stator holes. Our results also suggest that the clearance between the rotor and the stator has less influence on the homogenization effect than the hole diameter and number of holes. In the case of operation with a model product, we obtained the same trend for operation with water. From this fact, we consider that the performance estimation using C_h has a high degree of adequacy. The total energy dissipation rate that was contained in C_h could well account for the mean drop diameter in relation to mixing time. Our results demonstrate that we can compare and evaluate the homogenization effect for different configurations of rotor-stator mixers using the calculated C_h of the water mixing operation without actual product trials. This information could be useful for determining the optimum mixer design and appropriate mixer selection.

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A new two-phase atomizer used in the fluid catalytic cracking (FCC) process which has recently been studied experimentally, is modeled in three dimensions in a lagrangian framework by using a computational fluid dynamics (CFD) method. Special emphasis is placed on the study of the liquid atomization. The atomizer is used to quantitative tests in an air-water cold system in combination with a particle dynamics analyzer (PDA). Linearized instability sheet atomization (LISA) model is employed to simulate the water atomization process. The effects of the distance from the nozzle outlet on the droplet size and velocity distribution in the downward spray are studied. Predictions of droplet diameters, trajectories, and velocities are made and they are compared with relevant experimental results; the predictions and results are found to be in good agreement.

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To obtain a desired polymorphic composition of MPPO (4-(1-(2-(3-methoxyphenethyl)phenoxy)-3-(dimethylamino) propan-2-yloxy)-4-oxobutanoic acid), operation conditions were sought for seeded and drowning-out batch crystallization. Polymorphic mixtures having the same composition with the seed were obtained by controlling the seeding temperature, because it determined the supersaturations for the crystallization of both polymorphs. Analyzing the changes in the solution concentration and monitoring the particle behavior with FBRM, different crystallization behaviors between the polymorphs were made clear.

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This paper presents an experimental and numerical study on the occurrence of microexplosion in water-in-oil emulsion droplets. Experiments are performed for a single water/n-hexadecane emulsion droplet heated in an electric furnace. The volume fraction of water in the emulsion varies from 0.1 to 0.3 and the furnace temperature ranges from 973 to 1173 K. A mathematical model used in the numerical simulation describes the unsteady heat conduction in the emulsion droplet and the homogeneous bubble nucleation in the dispersed water droplets. Throughout the experiments, microexplosion is observed when droplet temperature is about 473 K. An increase in the furnace temperature decreases the microexplosion droplet temperature, and an increase in the water content decreases the microexplosion droplet temperature. In the numerical simulation, the strength of microexplosion when the water droplet temperature reaches the superheat limit is estimated from the homogeneous bubble nucleation rate. The strength of microexplosion peaks near the surface of an emulsion droplet. A water droplet heated to the superheat limit evaporates explosively. Furthermore, water droplets rapidly heated to the superheat limit in the higher furnace temperature evaporate explosively, so that the temperature of the droplet center is low compared with the lower furnace temperature. Although water content has no influence on the temperature of water droplets, an increased number of water droplets proportional to the water content indicates an increase in bubble nucleation. Therefore, higher water content is favorable for microexplosions, which indicates the occurrence of microexplosion at a lower droplet temperature.

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Enhancement of sonochemical reaction with the addition of aluminum powder in a sonoreactor is studied. The decolorization reaction between iodine and disodium hydrogenphosphate in a starch solution in the presence of aluminum powder proceeds at a maximum of 2 times faster than that in the absence of aluminum powder. The fast liquid flow is observed due to the reflection at the surface of the aluminum powder, which is in the shape of flakes in the water. The effect of the amount of aluminum powder on the chemical reaction is investigated.

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Chemical processes constitute strongly nonlinear systems, and such systems typically have multiple steadystate solutions. However, it is difficult to obtain all the steady-state solutions for a given system. In addition, the various steady-state solutions are likely to differ in terms of stability, which should be taken into account for practical applications. Due to the complexity of nonlinear systems, it is difficult to solve them manually.With the widespread use of computers and information technology, several nonlinear system analysis tools have been developed, facilitating the nonlinear analysis of chemical processes. In chemical processes, steady-state solutions as well as the stability of the solutions are simultaneously considered. After a survey of several existing analysis tools, we propose an analysis tool using a browser and server architecture design that rapidly finds steady-state solutions to nonlinear dynamic equations for chemical processes and simultaneously determines the stability of these solutions.Two examples are presented to demonstrate the effectiveness of this tool.

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To enzymatically hydrolyze cellulose of rice straw to glucose, the effect of pretreatment of rice straw with 15 strains of basidiomycetes is evaluated in terms of the quantitative changes in the components of pretreated rice straw and their susceptibility to enzymatic hydrolysis. Pleurotus ostreatus was found to be one of the most suitable white-rot fungi for biological pretreatment of rice straw. Of 11 strains of P. ostreatus tested,ATCC 66376 was found to have the properties superior to the other strains. Thus, in the pretreatment for 48 d, P. ostreatus ATCC 66376 degraded 39% Klason lignin and retained 79% cellulose in the pretreated rice straw. When the rice straw pretreated with this fungus was hydrolyzed with a commercial cellulase, the net yield of glucose determined on the basis of the weight of cellulose fraction of the untreated rice straw was the highest.

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This paper presents an immobilizing technique for copper ions on a substrate through a nanoscale thin film containing pyrrole groups. The nanoscale polypyrrole thin film covalently bonds to a substrate through a chemically adsorbed monolayer (CAM) containing pyrrolyl groups. We used 12-(1′-pyrrolyl)-n-undecyltrimethoxysilane (PUMS) as a chemical adsorbent molecule to form PUMS-CAM. Then a polypyrrole thin film was prepared on the PUMS-CAM by oxidative polymerization. For characterizing the PUMS-CAM and the polypyrrole thin film, we performed contact angle measurement, X-ray photoelectron spectroscopy (XPS), and film thickness measurement with ellipsometry. The water contact angles on the silicon substrate covered with PUMS-CAM and with PUMS-CAM and polypyrrole thin film were about 67.3° and 60.3°, respectively. XPS spectra exhibited binding energies of 285.0 eV for C1s and 400.0 eV for N1s. These results indicate that the PUMS-CAM and the polypyrrole thin film were prepared on the substrate. The film thicknesses of PUMS-CAM and polypyrrole thin film were approximately 1.5 nm and 2.3 nm, respectively; therefore, this indicated that PUMS-CAM and polypyrrole thin film were in the nanoscale. In addition, XPS was also applied to confirm the immobilization of the copper ions on the substrate. The results indicate the formation of the complex between the copper ions and the nitrogen atoms of the pyrrolyl groups. Therefore, this technique for immobilizing metal ions should be useful for many applications in plating industries.

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The catalytic combustion of toluene over mixed Cu–Mn oxides supported on cordierite is investigated in this paper. The catalysts were prepared by the incipient wetness method and characterized by XRD, BET and TEM. Five kinds of cordierite-type compounds containing different amounts of Cu²⁺ and Mn²⁺ ions were prepared (the mole ratio of Cu²⁺:Mn²⁺ varied as follows: 1 : 1, 1 : 2, 1 : 4, 2 : 1 and 4 : 1). Calcination of the precursors at 500°C resulted in mixed oxides and all calcined materials proved extremely active in catalytic combustion of toluene, in which the Cu²⁺:Mn²⁺=1 : 2 (forming CuMn₂O₄) was found to have the highest activity for toluene oxidation and T_90% was about 200°C. The objective of this study was to investigate the catalytic properties of Cu–Mn/cordierite catalysts prepared at different mole ratios, in order to obtain some information to prepare an efficient and highly active catalyst for catalytic combustion of volatile organic compounds at low temperature.

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