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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A double-pass parallel-plate mass exchanger under asymmetric wall concentrations is designed by inserting in parallel a permeable membrane to improve the device performance. A mathematical model was formulated theoretically for such double-pass forced-convection mass exchangers, as referred to conjugated Graetz problems. Linear superposition was introduced to analytical solutions of the resultant partial differential equations, which consists of an inhomogeneous solution with respect to the non-homogeneous boundary condition and a homogeneous solution is obtained with the use of an eigenfunction expansion in a power series. The analytical results show that the mass transfer efficiency of this double-pass parallel-plate mass exchanger is considerably enhanced as compared to that of a single-pass device by suitably adjusting the permeable-membrane position. Economic consideration in terms of the mass transfer efficiency and power consumption increment for double-pass operation is presented.

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Effect of eccentrically located position of impeller on mixing time was investigated in agitated vessels of different bottom shapes. The impellers used were a 4-bladed propeller and a 6-bladed flat paddle, which were commonly used in process industries, and the bottom shapes tested were a cone-fillet, a fully profiled and an ellipsoid bottom in addition to a flat bottom. The effect of off-bottom clearance of impeller on mixing time was also investigated at optimum eccentric locations for both impellers. For propeller, mixing times for all eccentric location covered in this work (e/R = 0.25–0.50, e: distance from shaft to center line of tank, R: radius of tank) became short drastically compared to those for centrally located for all bottom shapes and there was no significant effect of bottom shapes on mixing time. On the other hand, for flat paddle, mixing times were decreased proportionally with an increase in e/R. At optimum eccentric locations, those are e/R = 0.33 for propeller and 0.50 for flat paddle, the mixing times for propeller decrease drastically and then increase slightly with an increase in off-bottom clearance for all bottom shape and those for flat paddle decrease almost proportionally with an increase in off-bottom clearance but differed more or less according to the bottom shapes.

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The Induction time in CO₂ hydrate crystallization has been measured in a batch system under various experimental conditions. Correlation of the induction time with the solution supersaturation depicted by the Classical Nucleation Theory (CNT) led to determination of the interfacial tension between CO₂ hydrate and water at various temperatures, pressures and solution concentrations. The experimental data have indicated that the induction time decreases with increasing solution concentration at any constant temperature, while the interfacial tension increases with rising temperature. The theory can satisfactorily predict the experimental data. Furthermore, an empirical correlation, based on the famous power law for the rate of nucleation, has been applied and the order of nucleation is thereby obtained. Calculated values for the interfacial tension have been compared with predictions obtained by two conventional models.

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Iron oxide supported on activated carbon (IO/C) was prepared by a process based on homogeneous precipitation. The iron oxide content and specific surface area of the IO/C were varied by varying the ratio between initial amounts of activated carbon and iron(II) chloride tetrahydrate. Citric acid was used as a dispersant of iron oxide particles on activated carbon. The size of the magnetite particles in the IO/C prepared in the presence of citric acid was decreased with an increase in the concentration of citric acid at a constant magnetite content. The saturation magnetization of the IO/C varied from 0.5 to 39.9 emu/g according to the composition, content, and size of the iron oxide particles.

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The present paper deals with the effect of di- and tri-n-octylamine (DOA and TOA) dissolved in non-polar diluents or the mixture of non-polar diluents and modifier on the extraction of L-lactic acid from aqueous solutions. The amount of lactic acid extracted to the organic phase at equilibrium is dependent on the initial concentration of lactic acid in the aqueous phase as well as on that of amine in the organic phase. The results confirmed that almost the entire portion of lactic acid can be effectively extracted when the DOA concentration exceeds the initial concentration of lactic acid in the aqueous phase, and that TOA has little ability for the extraction when it is dissolved in non-polar diluent. Adding a modifier (decanol) to a non-polar diluent is also demonstrated to be effective for improving the extraction ability of TOA. The influence of the equilibrium pH value on the distribution ratio of lactic acid can be reasonably characterized by modifying the conventional ion-pair extraction model.

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This paper presents the permeation properties of monodispersed PMMA and silica particles with an average diameter of 150 and 200 nm, respectively, through MF membranes in dead-end mode under various conditions. In this study, it has been elucidated that the zeta potential of particles is one of the most important factors in determinating the permeation properties of PMMA and silica particles through MF membranes; larger repulsive force between the membrane and particles or between the particles themselves prevent particles from adhering onto the membrane surface, resulting in excellent permeation being maintained in the case of the silica particles. Furthermore, by conducting permeation tests systematically under various experimental conditions, it has also been shown that it is important for maintaining good permeation of particles to set conditions in which the number of particles which access each pore per certain time is sufficiently small, since particles cannot permeate through the membrane once the membrane is fouled by rejected particles.

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Used X-ray and lith films are composed of a protective layer, a gelatin layer (photosensitive layer) that contains silver particles, and a base poly(ethylene terephthalate) (PET) layer. In stainless steel tube reactor, used films were immersed in water and gelatin in both protective layer and gelatin layer was hydrolyzed under subcritical condition. After reaction for 5 min at 175°C, the entire amount of gelatin was decomposed, and the PET film and silver particles were recovered independently. In the case of the lith film, incubation at 200°C for at least 5 min was required for the complete decomposition of gelatin. Gel permeation chromatography (GPC) analysis of the water-soluble reaction mixture indicated that the average molecular mass of water-soluble gelatin decreased over time.

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This paper addresses the addition of internal heat integration to the pressure-swing distillation (PSD) process used in the separation of binary pressure-sensitive azeotropes. The primary step in the process design is to determine the pressure elevation from the low- to high-pressure distillation columns, followed by the design of internal heat integration between the two distillation columns. A general procedure is suggested and illustrated through the separation of an acetonitrile–water binary mixture, which forms pressure-sensitive minimum-boiling azeotropes. Comparisons are made between the conventional and the internally heat integrated PSD processes. It is demonstrated that breaking pressure-sensitive azeotropic mixtures can be made more economical than the current practice with conventional PSD processes. However, the degree of cost reduction is strongly dependent upon the properties of the mixtures to be separated.

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Mistakes in inspection, maintenance and work are the main causes of incidents that result in losses in plants as well as casualties of workers and neighboring residents. Thus, the permit-to-work (PTW) for safe work plays a key role in preventing incidents. The most important function of the PTW is to present various work-related potential hazards and utilize them for safety management by workers and managers. This paper presents a practical framework including detailed configurations of the hazard inventory in order to enable companies to implement the Job Safety Analysis (JSA) embedded in the PTW system that is most appropriate for identifying hazards, but difficult to obligate due to the heavy workload from a great number of work permits. This framework is characterized by categorization of hazards into task-level and job-level and the safety management system (SMS)-linked structure for supporting JSA and sound hazard data management. Furthermore, the process of implementing this framework into a working system linked to the SMS/PTW system of KOGAS and its effective results are presented. Ultimately, this paper demonstrates a practical framework that enhances job safety and the efficiency of work when implementing obligatory JSA, which should be ideally embedded in the PTW system for the safety of the most polymorphic work.

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The growth and red pigment production of Monascusruber on rice starch agar were studied by following the time courses of 1) length and tip number of aerial and substrate hyphae generated from single spores and 2) radius and pigment absorbance of colony. Logarithmic increases with time in hyphal length and tip numbers were observed during the first 0.92 d for substrate hyphae and 1 d for aerial hyphae. The specific growth rates estimated from the hyphal growth were 6.2 d⁻¹ for substrate hyphae and 5.5 d⁻¹ for aerial hyphae. These results closely agreed with that of 6.1 d⁻¹ obtained from the extension of colonial radiuses. Doubling time suggested from this specific growth rate is 0.114 d. The pigment formation was found to delay for 35 doublings in hyphal length extension since spore inoculation. Careful inspection showed that red pigment was locally formed by upper part of substrate mycelium.

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The present study investigates continuous gas phase stereoselective reduction catalyzed by commercial thermophilic alcohol dehydrogenase. The alcohol dehydrogenase and cofactor β-nicotinamide adenine dinucleotide phosphate were simultaneously immobilized on non-porous spherical glass beads. The reduction of 4-methyl-2-pentanone to (S)-4-methyl-2-pentanol with concomitant cofactor regeneration by 2-propanol was employed as a model reaction. According to the differing buffer pH dependence of the enzyme activity on both substrates, the maximal reactivity was obtained at a pH of 7.5 used for immobilized enzyme preparation. Owing to the higher stereoselective production, the water activity in the feed gas phase and reaction temperature were optimized at 0.9 and 333 K, respectively.

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The influence of crystal orientation on measured size is discussed for comparison between crystal size distribution (CSD) obtained by simulation and the ones by experimental measurement. In the simulation in which the CSD is calculated, the size should be defined as a characteristic dimension. On the other hand, the measured size to be compared with the calculation result does not always represent the same definition of crystal size. In most cases, the measured value is affected by crystal orientation, crystal shape and the measurement method itself. Considering this situation, the gap between the characteristic size and measured size were estimated by numerical calculation in the case of sieve diameter and Feret's diameter, which are widely used in crystallization analysis. The estimation was proved to be reasonable by testing the experimental data. It is implied to be important to evaluate the effect of crystal orientation on measured size when comparing simulated CSD and actual data.

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