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)
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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As part of our systematic study on physicochemical characterization of ionic liquids, we carried out new measurements of electrical conductivity for aqueous solutions of four ionic liquids at normal atmospheric condition for temperatures up to 353.2 K. The ionic liquids considered were 1-butyl-3-methylimidazolium chloride [Bmim][Cl], 1-butyl-3-methylimidazolium bromide [Bmim][Br], 1-butyl-2,3-dimethylimidazolium tetrafluoroborate [Bdmim][BF₄], and 1-butyl-2,3-dimethylimidazolium hexafluorophosphate [Bdmim][PF₆]. The electrical conductivity was measured using a commercial conductivity meter and the experimental uncertainty in the measurement was estimated to be ±1%. In this paper, the conductivity data are reported as a function of temperature and composition. A modified form of the Arrhenius equation was used to correlate the temperature dependence and composition dependence of the investigated ionic liquid systems, and the obtained correlations were found to be satisfactory.

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The study of fifteen possible chemical reaction in the SiCl₄ hydrogenation system in Siemens process based on the thermodynamic data for related pure compositions are reported in this paper. Curves of ΔG_m^θ-T for the 15 chemical reactions in the system have been fitted. The five independent reactions in the process have also been obtained and the relations of Κ_p^θ and temperature have been fitted. Furthermore, diagrams of the equilibrium gas phase composition versus temperature under pressures of 1 atm, 3 atm, and 5 atm and feed mole ratios (χ_H2 / χ_SiCl4) of 2 : 1, 3 : 1, and 4 : 1 are present herein. Finally, the influencing factors (such as temperature, pressure and the feeding molar ratio) on the conversion ratio from SiCl₄ to SiHCl₃ have been studied. Diagrams of the η-conversion ratio are presented as a function of temperature, pressure and feed mole ratio, respectively. The optimum operation parameters in the actual production are determined by thermodynamic and kinetic studies. The results show that the conditions of 1100°C, 3 atm and feed mole ratio (χH₂ / xSiCl₄) of 4 : 1 are most preferable. Under these conditions, the conversion ratio from SiCl₄ to SiHCl₃ is 24.81%, contrary to the less than 20% in actual production.

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The experiment was performed in a flat-bottomed cubic tank and equipped with a down-pumping 3-blade CBY propeller, investigating solid–liquid two-phase flow in the near-wall region by using 2D-PIV technique. Flow fields with ten different volumetric particle concentrations were investigated, including the single-phase flow. Because measurement is taken in the plane which is 2 mm from the wall, and root-mean-square velocity in the radial dimension could be omitted compared to the other two dimensions, flow field is considered to be two-dimensional. The mean velocity, turbulent kinetic energy and turbulent dissipation rate and their relationship with particle concentration were obtained and examined in this work. The increasing particle concentration decreases the flow mean velocity but increases the turbulent dissipation rate, while the turbulent kinetic energy (TKE) presents a complicated trend. When the particle concentration is below 0.9%, as in most previous studies did, TKE is attenuated; when the concentration grows up to 4%, TKE increases as well.

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The ideal requirements for highly efficient evaporative crystallization in batch or semi-batch type operations are a high crystal growth rate, a high density of suspended crystalline particles in a slurry and a sharp crystal size distribution. On the other hand, the initial seed crystal conditions are also very important because they affect the crystal size and distribution during the entire period of operation. In the present study, the influence of seeding conditions (average diameter and mass) and heating rate on both the crystal growth rate of sodium chloride (NaCl) and the crystal size distribution were investigated in an optimal design draft-tube stirred vessel containing high suspension density slurries of sodium chloride particles up to 30 vol%. In order to determine the optimal seeding conditions to simultaneously achieve a high crystal growth rate and narrow size distribution, an optimal operation index I_op has been defined based on a comparison of the experimental data and a model calculation with the assumption of ideal crystal growth. The results show that I_op correlate with the particle number of seed crystals and have a maximum value. With I_op correlation, the appropriate seeding conditions for achieving a high crystal growth rate and sharp size distribution have been determined.

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High suspension density slurries generally require high-power stirring, which can introduce a large amount of particle abrasion following particle collisions, and subsequent secondary nucleation. In this study, the influence of stirring operation and suspension density on evaporative crystallization of a high-density suspension of sodium chloride in continuous operation was investigated for an optimally designed draft-tube stirred vessel based on the time evolution of the number of crystals and the particle size distribution. For highly efficient evaporative crystallization in continuous operation, the particle suspension density should be kept high to eliminate excess nucleation with large particle surface areas. The impeller speed should be somewhat higher than the condition at which particles just become completely suspended to prevent particle agglomeration.

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A dual purpose absorbent Alginate-modified polyurethane (APU) has been prepared for the removal of residual aluminum ions by adsorption from treated wastewater. The structure of APU was confirmed by Fourier transform infrared (FT-IR) spectroscopy and proton nuclear magnetic resonance (¹H-NMR) spectroscopy. Physical characterization was preformed according to the BET method. Surface analysis using SEM/EDS revealed that an average of 0.57% aluminum by weight was adsorbed on APU. The adsorption isotherm of aluminum for APU fitted well to the Freundlich model. The analysis kinetic data suggests that adsorption of aluminum follows pseudo-first-order kinetics. The adsorption of aluminum on APU increased slightly from 25 to 35°C, indicating endothermic adsorption. The activation energy of adsorption, 8.16 kJ/mol, characterizes the dominant chemiosorption nature of this adsorption. The optimum pH for aluminum adsorption on APU (applied pH: 3–8) was found to be within the pH range of wastewater effluent. The adsorption capacity of APU for aluminum using real wastewater effluent was 3.8 mg Al/g, which demonstrates the feasibility of applying APU to the treatment of water of complex compositions.

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The compositions and the physical properties of mixtures are required to simulate multi-component batch distillation operations. In this study, temperature and accumulated distillate are measured as a function of time by use of a simple distillation apparatus. Initial compositions and physical parameters are estimated from this measurement data by a dynamic mathematical model, to examine the extent to which batch distillation operations can be predicted. For an ideal and a non-ideal solution system, the following three types of value estimation are examined: (I) compositions only, (II) parameters of one component, and (III) compositions and parameters of one component. The compositions could be estimated with sufficient accuracy. As for the physical properties, after devising a method for reducing the number of parameters, it is found that a batch distillation operation can be industrially designed from the estimated results.

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We have developed a new type of absorber using a gas–liquid two-phase plunging jet, based on an ejector-type nozzle equipped with a perforated plate. One characteristic of an impinging gas–liquid two-phase jet is described by (k̅_LA)_T, the product of the liquid-phase mass transfer coefficient and the gas–liquid interfacial area in the gas bubble dispersed phase. We studied the dependence of this product on the structural configuration of the nozzle and investigated the mass transfer mechanism using a coaxial bi-zonal model. The theoretical results were in good agreement with the experimental results. The (k̅_LA)_T value for this absorber was found to be larger than that for a conventional single-phase plunging-jet absorber.

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The effect of corrosion inhibitors such as CuCO₃, CuSO₄, and Na₂SO₃ on the oxidation of MEA has been investigated. The products of oxidative degradation of MEA were analyzed with or without the corrosion inhibitors. The corrosion inhibitor effects on the oxidative degradation of MEA and the extent of oxidative degradation is in the order CuCO₃ > CuSO₄ > MEA without inhibitors > Na₂SO₃. There was no difference in absorption/desorption rates among MEA solutions with and without the corrosion inhibitors. Among the products of the oxidative degradation of MEA, formate and acetate were dominant degradation products and nitrites and nitrates were also present in large amounts. The corrosion inhibitors CuCO₃ and CuSO₄ acted as catalysts for oxidative degradation of MEA. CuCO₃ and CuSO₄ influenced the formation of carboxylic acids (formate, acetate, and oxalate), but did not influence the formation of nitrogen products (nitrites and nitrates). Na₂SO₃ slightly inhibited the oxidative degradation of MEA and did not produce more oxidation products than CuCO₃ and CuSO₄.

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Rice hull was calcined to rice hull ash (RHA) at 500°C under 20 mL air s⁻¹ for 50 min. The RHA thus prepared has been found to adsorb nickel(II) ion from aqueous solution efficiently. Experimental results indicated that the rate of adsorption of nickel ion and the adsorption of nickel ion at equilibrium were increased upon decreasing RHA dosage. They were also increased with increasing initial nickel concentration or adsorption temperature. On the other hand, they were found to remain unchanged when the initial pH was increased from 2.3 to 5.6, or the stroke speed was changed in the range of 30–180 stoke min⁻¹. The kinetic data obtained obeyed the pseudo-second-order rate equation. An empirical equation correlating the relationship between the adsorption of nickel ion and the adsorption time was also determined.

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After adding Al₂(SO₄)₃ to wastewater that was discharged from a flue-gas desulfurizer, alkalization by solid Ca(OH)₂ or NaOH solution was carried out in order to examine the effects of the reaction conditions such as the concentration of the Al₂(SO₄)₃ that was added and the pH of solution on the precipitation of the boron in the wastewater. Higher concentrations of Al₂(SO₄)₃ added into the wastewater resulted in the precipitation of larger amounts of boron. The amount of precipitated boron increased with an increase in the pH of the reacted wastewater solution and attained the peak or plateau value at pH values in the range of 10 to 12. The concentration of the precipitated boron was in proportion to the concentration of precipitated Al(OH)₃ at pH <10 and to the concentration of precipitated ettringite at pH >10. Alkalization by Ca(OH)₂, rather than by NaOH, promoted the formation of ettringite and thereby promoted the removal of boron. It was found that if the SO₄/Al, Ca/Al, and OH/Al molar ratios of the feed wastewater solution were higher than the corresponding theoretical molar ratios of ettringite, the formation of ettringite was promoted.

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