Editor-in-Chief:
Hiroyuki Honda (Nagoya University)

Associate Editors-in-Chiefs:
Manabu Shimada (Hiroshima University)
Takao Tsukada (Tohoku University)

Editors:
Ryuichi Egashira (Tokyo Institute of Technology)
Jun Fukai (Kyushu University)
Choji Fukuhara (Shizuoka University)
Takayuki Hirai (Osaka University)
Masahiko Hirao (The University of Tokyo)
Jun-ichi Horiuchi (Kitami Institute of Technology)
Eiji Iritani (Nagoya University)
Yoshinori Itaya (Gifu University)
Hideo Kameyama (Tokyo University of Agriculture and Technology)
Masahiro Kino-oka (Osaka University)
Toshinori Kojima (Seikei University)
In-Beum Lee (Pohang University of Science and Technology (POSTEC))
Shin Mukai (Hokkaido University)
Akinori Muto (Osaka Prefecture University)
Nobuyoshi Nakagawa (Gunma University)
Hiroyasu Ogino (Osaka Prefecture University)
Naoto Ohmura (Kobe University)
Mitsuhiro Ohta (Muroran Institute of Technology)
Hiroshi Ooshima (Osaka City University)
Yuji Sakai (Kogakuin University)
Noriaki Sano (Kyoto University)
Masahiro Shishido (Yamagata University)
Richard Lee Smith, Jr. (Tohoku University)
Hiroshi Suzuki (Kobe University)
Shigeki Takishima (Hiroshima University)
Yoshifumi Tsuge (Kyushu University)
Tomoya Tsuji (Nihon University)
Da-Ming Wang (National Taiwan University)
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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Sampling of particles smaller than 100 nm is of great concern for assessing the adverse health effects of airborne nanoparticles in both atmosphere and workplaces. Inertial filter (IF) is a new application of air filter, which is recently developed by the present authors to classify nanoparticles by passing aerosol through an air filter at a high filtration velocity. In the present work, we investigated the effects of fiber packing density and particle deposit on classification performance of IF to achieve 50% cut-off diameter of 100 nm for sampling nanoparticles. Unwoven stainless steel (SUS) fiber mat with diameter of 8 μm is used as a filter medium. It was found that, in inertial regime, the collection efficiency changes markedly with the packing density due to the interactions of neighboring fibers. As a result, by adjusting the filtration velocity to achieve 50% cut-off diameter of 100 nm, IF with various packing densities had almost the same classification performance, and a compressed filter is advantageous because it had a lower pressure drop. The influence of loaded particles on the classification performance was also investigated. It was found that, up to the collected particle mass of 1 mg, the effect of dust load is not significant. Therefore IF with a higher packing density is superior in achieving 50% cut-off diameter of 100 nm from the viewpoints of both initial and dust-loaded classification performance.

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Ethanol was separated from aqueous solutions through ultrasonic atomization. Ethanol enrichment was evaluated by determining ethanol concentration in condensates collected from atomized mist and vapor. The amount of collected mist and vapor accorded with the amount of liquid left from the atomization column. In the limited range of ethanol feed concentration below 30 mol%, the ethanol concentration in the condensates was affected by ultrasonic parameters such as frequency and input power. Ethanol enrichment was enhanced at higher frequencies and lower input power. The effect of ultrasonic parameters on ethanol enrichment was interpreted from the viewpoint of cavitation. Potassium iodide oxidation was conducted to examine the occurrence of cavitation, and the number of violently collapsing bubbles. The use of higher frequency and lower input power, which corresponded to enhance ethanol enrichment, resulted in a decrease in KI reactivity. This trend suggests that violently collapsing bubbles enhanced fragmentation of the bulk liquid where no separation mechanism works. Assuming that the surface excess of ethanol plays a significant role in the separation, possible routes of ethanol transfer from liquid to mist or vapor are suggested.

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A new separation technique, called stripping crystallization (SC), is applied in this work for the purification of a 2,6-xylenol/m-cresol mixture. Basically, SC combines distillation and crystallization to produce pure crystals based on the three-phase equilibrium. A thermodynamic model is proposed to simulate the three-phase equilibrium conditions during the SC operation. The experiments show that SC can be applied to purify 2,6-xylenol from a 2,6-xylenol/m-cresol mixture, while it is rather difficult to purify m-cresol. For purification of 2,6-xylenol, the recovery rate increases with increasing operating pressure, while the final purity of the product decreases with increasing operating pressure.

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The cooling crystallization of borax decahydrate has been investigated for the influence of temperatures on solubility, induction period and yield in order to establish the limits of conditions. Crystal morphology of borax decahydrate was studied by optical microscopy. Characterization of the crystals was performed by X-ray diffraction. The solubility curves were determined within the range of 0 to 25°C. The induction period was extremely short in seeded experiments compared with unseeded experiments. The yield was found to increase with decreasing temperatures. Microscopy observation revealed that as-grown crystals were significantly elongated in a direction parallel to the c-axis of the monoclinic system. The X-ray diffraction analysis indicated that the (002) plane of monoclinic system grew faster than the (120) plane at temperatures of 5 and 9°C. The results indicate that the temperature limit of borax decahydrate crystallization is 9°C.

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This paper presents a feasibility study of cryo-adsorption systems using low temperature adsorption materials for the on-board storage of hydrogen in a fuel cell vehicle. Charge and discharge validation experiments were performed using a 5 L semi-vehicle size tank. The tank was larger than the conventional lab scale test tank in order to clarify issues and evaluate the potential of this system for practical vehicle applications, and to provide targets for material development. Our results show that cryo-adsorption has a potential of higher hydrogen storage capacity in term of compactness and lightness than conventional high pressure tanks, provided that high volumetric density adsorption materials are available. Our results show that it is possible to obtain acceptable charge and discharge performance. They also show the necessity for further basic investigations into the heat transfer behavior during the charge and discharge of cold hydrogen into the system. In general, this concept is suitable for application in the context of a liquid hydrogen distribution infrastructure, which is widely used in industrial gas delivery today and is also expected to play an important role in hydrogen delivery systems for the transport sector.

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Hydrodesulfurization of dibenzothiophene (HDS of DBT) has been carried out over CoMo/Al₂O₃–TiO₂ catalystsin a batch reactor at 320°C and 5.5 MPa. The supports were prepared with different raw materials and nitrilotriacetic acid (NTA) was used as a chelator at different concentrations. X-ray diffraction, Fourier transform infrared spectroscopy, temperature programmed desorption of NH₃, and Brunauer–Emmett–Teller surface area experiments were used to characterize the catalyst samples. The results showed that the oxide prepared by an impregnation method with γ-alumina and tetraisopropyltitanate as the raw materials was the best support, having the highest surface area (239 m² · g⁻¹) and the highest acidity (1.112 mmol_NH3 · g⁻¹), and the catalyst with an NTA/Co mole ratio of 0.6 was the best sample, having a hydrodesulfurization activity value (on a pseudo first order kinetic constant basis) ~1.5 times higher than that of a CoMo/Al₂O₃ catalyst.

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The present study investigates CFD simulation of aqueous-organic two phase flow in microreactors with a guideline structure. The guideline structure was developed in order to stabilize and to maintain parallel flow of liquids within the microreactors. The CFD simulation can well predict the flow patterns observed in experiments. Upon determining the flow pattern and stability, it is reported that, with the presence of guideline structure, the interface became more curved and stable. Finally, the role of the guideline structure on the flow development was also investigated.

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The establishment of technologies for large-scale afforestation in arid lands for carbon fixation is important. However, arid lands can provide only small amounts of water for plant growth; therefore, effective water use is likewise a very important issue. The objective of this study, conducted near Leonora, Western Australia, was to establish a method for estimating the amount of water required for tree growth. This method is based on the nutrient flow in a tree, and it is accordingly necessary to examine the effects of various factors on the distribution of nutrients for the estimation of representative nutrients concentration in tree organ. In this report, the distribution of nutrients in tree organs was examined in Eucalyptus camaldulensis, one of the typical tree species in the area. The distribution of nutrients in tree organs was considered to be influenced by various factors, including organ type (leaf, branch, trunk, or bark), distance above ground of the sampling point, orientation of the tree, and height of the tree. However, it was clear that the nutrient concentrations of and biomass allocation to each organ are important factors for the estimation of representative nutrients concentration in tree organ. Further, it was shown that the calcium concentration clearly decreased, whereas the potassium concentration increased, with increasing vertical distance from the base of the trunk.

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In the present study, a magnetically separable photocatalyst (TiO₂/SiO₂/Fe₃O₄) has been prepared and used for the photooxidation of methyl orange (MO) dye. The effects of various reaction conditions such as dye concentration, catalyst dose, and pH on the reaction rate were investigated to enhance the photooxidation process. Thephotocatalytic oxidation of MO was found to follow half-order kinetics. The optimum reaction conditions were found to be a 2000 ppm TiO₂ catalyst dose in an acidic medium. A higher catalyst load had no effect on the degradation rate. The dye concentration negatively affected the reaction rate because of the reduced light transmittance inside the photoreactor. The catalyst could be reused several times with nearly the same activity and thus the final cost of the treatment process could be reduced.

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Afforestation is one of the most promising methods for the fixing of carbon dioxide. In this research, a target area of unused land, not competitive with food production and with a large area, was selected in the arid land near Leonora in Western Australia. It was necessary to select suitable tree species for afforestation in the target arid area. The objective of this work was to establish a method for the estimation of the amount of water used per net carbon intake. In this study, a method for the estimation of the water use efficiency (WUE) using nutrient tracers is suggested and established. Calcium was the most suitable nutrient for use as a tracer for this estimation method. The sampling strategies for the measurements were decided, and the nutrient concentrations in the tree organs and sap and content of carbon were determined. In particular, a method through which the calcium content in the sap is corrected using the calcium concentration in the organs of a tree was examined. It was confirmed that the WUE value obtained with this method was comparable to those determined by conventional methods. Finally, it is suggested that the present method for WUE determination is characterized by the advantages of short measurement terms and low cost.

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