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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Mechanical mixing with an impeller in continuous laminar flow is sometimes introduced to industrial processes. In glass producing industries, especially, mechanical mixing has a significant role in homogenising continuously flowing molten glass at high temperature and achieving high quality glass. Nevertheless, the mixing performance evaluation in a continuous flow system, especially incomplete mixed flow, has not been well studied. It is necessary to enable quantitative evaluation of mixing to enhance the development of new mixing technology in this field. In the present study, concentration distribution measurements of an injected tracer in continuous laminar flow were performed in the downstream area of an impeller to investigate the influences of the impeller speed and setting position. An evaluation method with the standard deviation calculated from the measured concentration of 15 electrodes in a channel showed good agreement with the visualization method and the effect of impeller speed and position on mixing could be quantitatively evaluated.

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Computational fluid dynamics (CFD) simulations were performed to study effects of the flow pattern on the mixing quality of floating solids in stirred tanks with up- and down-pumping pitched blade turbine (PBTU and PBTD). The variables about impeller design have influences in the flow pattern and four key ones, impeller diameter, clearance from tank bottom, blade angle and number, were investigated in this work. Euler–Euler multiphase model along with mixture k–ε turbulence model was adopted. The relative motion between rotating impeller and stationary baffles was modeled with the multiple reference frame (MRF) approach. The predicted results were compared and explained with the experimental or theoretical results in published literature. Qualitative and reasonable agreement was achieved.

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The formation of non-aggregated nickel nanoparticles by hydrogen reduction of nickel chloride has been studied in a tubular furnace reactor. A change in the proportion of non-aggregated particles in TEM images was observed using a rapid cooling of the entire aerosol produced in the reactor with jets of N₂ quenching gas and a Laval nozzle placed above the reactor. The proportion of non-aggregated particles was 38% for nickel particles produced without any cooling steps. When the aerosol was supercooled in the Laval nozzle after passing the jets of N₂ quenching gas, the proportion of non-aggregates was as large as 84%. It was found that the rapid cooling in the region downstream of the reactor is quite effective for preventing aggregation of particles.

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This study investigated the adsorption of lead ions (Pb²⁺) by activated carbon modified with potassium permanganate (KMnO₄). Activated carbon was chemically modified through impregnation with solutions of KMnO₄ (0.01 mol/L and 0.03 mol/L). Adsorption experiments from aqueous solutions containing known amounts of Pb²⁺ were explored in a batch system. The amount of Pb²⁺ adsorbed at different pH values, initial concentrations, sorbent dosages, contact times, and temperature were determined by atomic absorption spectrometry (AAS) in order to determine the optimum conditions for Pb²⁺ adsorption. Moreover, the effects of common ions like sodium, potassium, calcium, and magnesium on the adsorption capacity were also studied. The Pb²⁺ adsorption on modified and unmodified activated carbon conformed to the Langmuir isothermal adsorption equation. Overall the modified activated carbon exhibited a higher adsorption capacity and stronger chemical affinity than pristine activated carbon. The rates of adsorption were found to conform to pseudo-second order kinetics.

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The centrifugal separation of an emulsion–slurry containing oil droplets and colloidal SiO₂ particles was investigated using the microprocessor-controlled analytical photocentrifuge, LUMiFuge. The oil droplets and SiO₂ particles were completely separated after centrifugation due to the flotation of the oil droplets and the sedimentation of the SiO₂ particles, as a result of the density difference. The flotation velocity of the oil droplets and the settling velocity of the SiO₂ particles were larger than those of the single dispersions (oil-in-water (O/W) emulsion and SiO₂ suspension) with the corresponding volume fractions. The acceleration effects of flotation and sedimentation were examined using the flotation and sedimentation coefficients, in which the effect of centrifugal acceleration on the flotation and sedimentation velocities was cancelled. The flotation and sedimentation coefficients increased with increasing SiO₂ particle or oil droplet volume fractions in the emulsion–slurry, and the acceleration effect of the flotation coefficient was noteworthy due to the marked increase in the density difference between the oil droplets and the emulsion–slurry with increasing SiO₂ particle volume fractions. The flotation and sedimentation coefficients were experimentally described using two types of void functions, and accurately described the acceleration effect in the centrifugal separation of the emulsion–slurry.

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Non-catalytic hydrolysis of soybean oil using subcritical water is statistically optimized in a continuous flow reactor to produce fatty acids (FA). Response surface methodology (RSM) in combination with central composite design (CCD) is applied to evaluate the relationships between the FA content and processing parameters including reaction temperature, pressure, volumetric ratio of water to oil, and reaction time. The results show that optimum processing conditions for maximizing the FA content were 294°C, 12 MPa, a volumetric ratio of 1.8, and a reaction time of 22 min. The predicted FA content is 96.78% under the statistically optimized conditions, and this value is almost identical to the experimental value with an insignificant error of 0.67%.

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Gas phase pyrolysis of benzene was performed at 1,123, 1,173, and 1,223 K using a flow type reactor to examine the mechanism of the initial stage of coke (poly-aromatic hydrocarbons; PAHs) formation. The pyrolysis products including hydrogen, tar, and coke were quantified as the function of benzene residence time using gas chromatography, gas chromatography-mass spectrometry, LDI-TOFMS, and elemental analysis to establish the carbon balance within 95 to 105% for all of the experiments. Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) was applied to determine individual components in coke. Main tar components quantified were biphenyl (C₁₂H₁₀), terphenyl isomers (C₁₈H₁₄), quaterphenyl isomers (C₂₄H₁₈), phenanthrene (C₁₄H₁₀), and triphenylene (C₁₈H₁₂). Phenanthrene was found to be formed by the H-abstraction-C₂H₂-addition (HACA) mechanism and the other components were judged to be formed by the phenyl addition (PA) and the phenyl addition/cyclization (PAC) mechanisms. One of the smallest molecules identified within the coke was dibenzo[fg,op]naphthacene (C₂₄H₁₄) that is formed from triphenylene by the PAC mechanism. Larger molecules formed by the PAC mechanism and the HACA mechanism were also identified as coke components at the initial stage of pyrolysis. The phenyl addition to PAHs by the PAC mechanism and the HACA mechanism were judged to be main pathways to form larger PAHs. Main reaction mechanisms at the early stage of coke formation were suggested based on the detailed experimental data.

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Decomposition of bean curd refuse (Okara) was examined in hot compressed water at saturated steam pressure from 423 to 573 K. Bean curd refuse was fragmentated in water above ca. 423 K. The decomposition of bean curd refuse rapidly proceeded and almost finished within about 10 min at 473 K at which the yield of water soluble fraction attained about 45 carbon %. The conversion rate from water insoluble fraction to water soluble increased with increasing temperature and most of the bean curd refuse became water soluble fraction or acetone soluble one at 573 K. The yield of total saccharides was up to 38% and a large part of hemicellulose and cellulose in bean curd refuse would be able to become saccharides. Furthermore, water promoted the decomposition of water insoluble fraction to water soluble and 10 times of water relative to bean curd refuse by weight basis was enough for this promotion. The shaking of the reactor promoted the decomposition of bean curd refuse to both lower and higher molecular weight sides. Hot compressed water can be a useful solvent for the decomposition of bean curd refuse by the proper choice of temperature and amount of water.

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Collagen extracted from tissues by alkaline treatment has a different isoelectric point (pI≈5) than the commonly-used acid- or pepsin-treated collagen (pI≈9). In this study, the feasibility of using the alkali-treated collagen (AC) as a carrier of basic fibroblast growth factor (bFGF) for enhancement of angiogenesis was examined. AC hydrogels were prepared by chemically crosslinking AC molecules using glutaraldehyde (GA). We investigated the effects of GA concentration in AC gels on the degree of swelling of the gels in an aqueous environment and on the in vivo degradation rate of the gels. Horse cytochrome c (pI: 9.6), a model for bFGF (pI: 9.6), electrostatically adsorbed to the AC gels. Subcutaneously-implanted AC gels incorporating bFGF led to enhanced angiogenesis compared with bFGF-free gels. Thus, AC gels incorporating bFGF appear to be useful materials for (i) the enhancement of angiogenesis and (ii) tissue engineering scaffolds.

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We applied a microreactor to the synthesis of polymethylmethacrylate (PMMA) using a laboratory microreactor system with a production volume of 2–3 t per year, which enabled pseudo-continuous feeding by syringe pumps. When using a tube made of stainless steel, the values of the yield, number average molecular weight (M_n), and polydispersity index (PDI) reached 75.2%, 9.4×10³, and 1.88, respectively. These results were in good accordance with the reported ones and a product with comparable properties was obtained. Then, we performed a continuous synthesis of PMMA for 8 h using a medium scale microreactor plant with a production volume of 100 t per year, which provided continuous feeding by triple cam driven pumps. When using a tube made of polytetrafluoroethylene (PTFE), it was confirmed that a product was continuously obtained for 8 h, whose yield, M_n, and PDI were on average 66.2%, 8.8×10³, and 1.95, respectively. The variation in the yield, M_n, and PDI was within 5.7%, 4.5%, and 1.0%, respectively. For comparison, when using the laboratory microreactor system under the same reaction condition with a tube made of PTFE, the corresponding values of the yield, M_n, and PDI were 66.5%, 8.4×10³, and 2.04, respectively. The difference in the results between the above two microreactor systems was 4.8% at a maximum (in M_n). Therefore, the synthesis of PMMA was continuously performed using the medium scale microreactor plant and the comparability of the reaction performance between the above two microreactor systems was ensured.

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In this paper, 1-butylrpridinium bromide was synthesized, in which the solubility and regeneration of garlic stem in [BPy]Br and [BPy]Br /DMSO dissolution system were examined in the temperature range of 100–240°C. The results show that [BPy]Br can efficiently dissolve and degrade stalks, and DMSO can effectively improve the solubility of garlic stem and accelerates the dissolution rate at the optimum ratio of n_[Bpy]Br : n_DMSO=1 : 8. With the increase of dissolution temperature and time, the solubility of garlic stem in [BPy]Br and [BPy]Br /DMSO increased correspondingly. The regenerated and undissolved cellulose samples in pure ionic liquid and mixed solvent were characterized by FT-IR, XRD, TG-DTG and SEM. It was found that [BPy]Br significantly affected the structure and surface characteristics of the garlic stem. The garlic stem were degraded in the ionic liquid of [BPy]Br effectively, indicating [BPy]Br has good degradation ability to the cellulose.

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