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))
Kouji Maeda (University of Hyogo)
Shin Mukai (Hokkaido University)
Akinori Muto (Osaka Prefecture University)
Nobuyoshi Nakagawa (Gunma University)
Hiroyasu Ogino (Osaka Prefecture University)
Naoto Ohmura (Kobe University)
Mitsuhiro Ohta (The University of Tokushima)
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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Internally heat integrated distillation columns (HIDiCs) have attracted industrial attention since HIDiCs are expected to have a strong impact on energy savings in chemical industries. Particularly in Japan, large national research projects for HIDiCs have been conducted, and a HIDiC pilot plant has been constructed. The pilot HIDiC has shown energy savings of more than 60% compared to a conventional distillation column in the separation example of a twelve-component hydrocarbon mixture. In addition, several research projects on HIDiCs have been carried out also in Europe. In this paper, the overview and recent advances in HIDiC technologies of Japan and Europe are introduced.

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This work presents an evaluation of the acidity constants of 1-hydroxy-9,10-anthraquinone derivatives using electronic descriptors in four methanol/water mixtures with different volume percents and in isolation. An Onsager reaction field model was applied for charges, orbital energies, and dipole descriptors of solutes in the four different solvent mixtures with different volume percents. Each solute was placed in a cavity surrounded by a continuous dielectric constant medium, and the quantum chemical descriptors of the solute were calculated. Electrostatic potential energy descriptors of the isolated solutes were obtained using density functional theory. Relevant descriptors affecting the acidities of the anthraquinones were selected using a genetic algorithm (GA) method. Contributions of the selected variables to the prediction of the experimental acidity constant values were determined by applying a multi-layer perceptron-based feedforward artificial neural network (ANN). A proper model, reproducing experimental acidity constants within average absolute errors of less than 1.10% was achieved. The model proposed relatively higher contributions of dipoles (insolvent) and electrostatic potentials (in isolation) than the orbital energies, revealing the role of strong dipole–dipole interactions such as hydrogen bonds as well as halogen bonds in the proton dissociation process. The gaps between the HOMO and LUMO energies were found to contribute to the stabilization of anions leading to higher dissociation constants.

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The particle size and shape of hexanitrohexaazaisowurtzitane (HNIW) crystals are investigated in drowning-out crystallization. Since the ε-HNIW crystals are re-constructively transformed from raw HNIW with polymorphic forms, which are crystallized out by drowning-out crystallization, the particle size and shape of ε-HNIW crystals are predominantly determined by the growth process during the phase transformation. Due to contradictory contributions of crystallization conditions on crystal particle size and shape, the crystal particle size and shape are controlled by the antisolvent feeding rate within a range of the antisolvent feeding rate from 0.1–1.0 mL/min at ambient temperature. In addition, the ε-HNIW crystals are detected by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy, the thermal energies related with the solid-state phase transition from ε-HNIW to γ-HNIW and decomposition of HNIW showing dramatic differences in crystal particle size owing to the significant changes in crystal density using differential scanning calorimetry (DSC) and X-ray diffraction.

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Activated carbons (ACs) prepared by CO₂ activation of five different precursors and commercial coconut shell AC are used for benzene adsorption (5 ppmv) from air at relative humidities (RHs) of 0%, 50% and 70%. Benzene adsorption capacities of the ACs prepared in the laboratory are similar at RH 0%, but differ significantly in the presence of moisture. The negative influence of moisture on benzene uptake is greater in a case of the ACs with large amounts of surface polar sites. The average micropore sizes of the ACs up to 0.8 nm are beneficial for benzene adsorption at RH 70%, while the average micropore sizes above 0.8 nm are beneficial for benzene adsorption at RH 50%. The desorption of benzene from the ACs after adsorption has been examined by temperature programmed desorption (TPD) method. It was found that the desorption profiles of the ACs are similar at the same RH, suggesting that the adsorption of benzene occurred on similar adsorption sites in all ACs, despite the differences in their origin and in pore and chemical properties. At RH 70%, benzene is adsorbed only on the high-energy sites, which results in a shift of desorption profiles to higher temperatures.

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Polyamidoamine (PAMAM) dendrimers were loaded in mesoporous silica MCM-41, and its gas adsorption properties were evaluated for a N₂, H₂O, and CO₂ to examine whether it could be used for CO₂ separation. The mesoporous structure of MCM-41 was affected by the amount of dendrimers loaded. The behavior of N₂ and water vapor adsorption changed significantly with the PAMAM loading rate owing to the plugging of the MCM-41 pores by the excess amount of PAMAM dendrimers. In dry conditions, although the CO₂ adsorption capacity at high CO₂ partial pressures gradually decreased with an increase in PAMAM loading, MCM-41 loaded with PAMAM at a high loading rate showed slightly larger CO₂ adsorption capacity at low CO₂ partial pressures, which resulted from the chemical adsorption of CO₂ by amines. In the presence of water, neat MCM-41 showed a significant decrease in its CO₂ adsorption capacity similar to the case of MCM-41 loaded with PAMAM at a low loading rate. On the other hand, for a high loading rate, the adsorbent showed much higher CO₂ adsorption capacity than the neat MCM-41. Water condensation in the pores must lead to a significant decrease in the CO₂ adsorption capacity. The CO₂ adsorption capacity could be determined from the pore structure after the modification as well as from the nature of the modified amines.

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The focus of the present paper is the application of a novel optimization algorithm called an imperialist competitive algorithm (ICA). In this algorithm, the cost function, which is a function of the input parameters, has to be optimized. In the present research, our cost function is the average free convection heat transfer from a horizontal isothermal cylinder located underneath an adiabatic ceiling. The input parameters are the ratio of the cylinder spacing from the adiabatic ceiling to its diameter (L/D), varying from 0.1 to 2.4, and the Rayleigh number, varying from 5500 to 40000. After data reduction, the regression equation of the average Nusselt number of the cylinder surface was obtained as a function of the Rayleigh number and the cylinder spacing ratio (L/D). The cost function was then optimized using the ICA. The results show that the proposed algorithm is powerful enough to be used for optimizing the cost function. According to the results obtained, the minimum Nusselt number corresponds to the optimum distance between the adiabatic wall and the cylinder.

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A mathematical model has been developed to predict mass and heat transfer during the steam generation process in a novel zeolite–water adsorption heat pump system. This model features a three-phase calculation and a moving water–gas interface. The calculations were carried out in the zeolite–water and zeolite–gas regions. An enthalpy form is adopted to account for water evaporation. Model outputs are compared with experimental results for validation. The thermal response in the reactor is well simulated with a relative error between the calculated and experimental steam mass of 0.6% to 1.9%. The effects of operational temperatures on the steam mass are also investigated numerically. Raising the water temperature rather than zeolite temperature enhances the mass of steam produced. The peak temperature in the reactor increases from 300 to 311°C as initial zeolite temperature rises from 80 to 120°C.

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A new methodology for solving black-box optimization problems by the continuous approach has been developed in this study. A discrete Fourier series method was derived from the conventional Fourier series formulation and principles associated with the discrete Fourier transform, and used for the reformulation of black-box objective functions as continuous functions. A stochastic global optimization technique known as Particle Swarm Optimization (PSO) was then applied to locate the global optimal solutions of the continuous functions derived. The methodology was first applied to the solution of a black-box optimization problem that was simulated on the basis of the Himmelblau function. It was then applied successfully to the optimization of the conditions used for various types of experiments such as those involving the permeation of nimodipine through human cadaver epidermis, lipid production, and the production of a human interferon beta by the recombinant bacteria Escherichia coli. The discrete Fourier series method coupled to the PSO algorithm is thus a promising methodology for solving black-box optimization problems via the continuous approach.

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An isothermal reactor in which reaction solutions can be controlled at constant temperature under constant microwave irradiation has been developed for investigating microwave effects on chemical reactions. A structure was devised in which a heat-transfer medium with a low dielectric loss factor, which hardly absorbs any microwaves, flowed outside a reaction tube, and the basic structure of the reactor was designed using electromagnetic simulation. In addition, the microwave effects on two reactions (homogeneous reaction and heterogeneous reaction) were investigated using the developed isothermal reactor. The Suzuki–Miyaura coupling reaction as a homogeneous reaction and the Sonogashira coupling reaction with solid palladium catalyst supported inside a reaction tube as a heterogeneous reaction have been examined. The results show that the yields obtained by microwave heating and oil–bath heating are almost equal, and thus microwaves have no effects in the homogeneous Suzuki–Miyaura coupling reaction experiment. On the other hand, the yield obtained by microwave heating is 2.4 times higher than that obtained by oil–bath heating in the heterogeneous Sonogashira coupling reaction experiment, in which the temperatures of reactant solutions in both microwave heating and oil–bath heating were kept at 373 K using the isothermal reactor. It is believed that palladium catalyst supported inside a reaction tube is heated locally by microwaves, which enhances the localized reaction rate and improves the yield. In addition, the temperature of the catalyst is inferred to be approximately 403 K by microwaves.

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Electrospinning of sols obtained through hydrolysis and partial condensation of tetraethoxysilane is a method for preparing silica nanofibers. The effects of the parameters used in the nanofiber fabrication process on the diameter and morphology of the fibers were investigated for controlling the diameter of the resultant fibers. The thinnest smooth fibers (average diameter: 305 nm) were obtained under the following conditions: sol viscosity, 0.14 Pa·s; applied voltage during electrospinning, 25 kV; needle-to-collector distance, 10 cm; and flow rate, 8 mL/h. Decreasing the viscosity of the sol to less than 0.1 Pa·s resulted in the generation of beads and beaded fibers. Thicker fibers were obtained by increasing the viscosity and decreasing the applied voltage during electrospinning. In contrast to the viscosity and applied voltage, the needle-to-collector distance, which was varied in the range 5–15 cm, and the flow rate of the sol (2–11 mL/h) extruded from the needle did not influence the diameter of the fibers significantly.

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The introduction of a fluorine-base polymeric surfactant has showed a 10% enhancement in solvent evaporation rates within a certain range of polymer concentrations in cellulose acetate butyrate (CAB)/methyl ethyl ketone (MEK) solutions. Weight loss measurements have revealed that the drying rate initially increased and subsequently decreased with increasing surfactant mass fractions (P). The normalized drying rates obey a single master curve, and show a peak at a blending ratio of P∼0.1. The results suggest that surfactant addition is a promising method for achieving higher solvent diffusion rates in liquids.

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The storage rate and amount of hydrogen in tetrahydrofuran hydrate were investigated by means of pressure–volume–temperature measurement under three temperature conditions. The absorption process of hydrogen in tetrahydrofuran hydrate was expressed as a dynamical model based on classical shrinking core model, which included two steps: hydrogen inclusion (containing adsorption, entrapment, and delocalization processes) at the surface of tetrahydrofuran hydrate and hydrogen diffusion through the formed layer of hydrogen+tetrahydrofuran mixed hydrate. The rate constant of surface reaction and/or diffusion coefficient of hydrogen depended on the porosity of small cages in tetrahydrofuran hydrate at equilibrium state. The storage amount of hydrogen at all temperatures would reach the maximum value of 2.0 mol (hydrogen)/mol (tetrahydrofuran) at a certain pressure. At the same pressure, the storage amount of hydrogen increases as the temperature decreases.

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Reservoirs frequently require dredging to remove accumulated sediment. This sediment is currently unused, but represents a possible source of humic acids (HAs) that have potential as iron-binding supplements in fertilizers. In order to evaluate the utility of these materials, we investigated the structural features and Fe(II)-binding constants or capacities of some HAs obtained from reservoir sediments. The histidine content in the HAs was correlated to the Freundlich binding constant for an Fe(II)-HA complex, indicating that indole moieties in histidine function as strong binding sites for Fe(II). The binding capacities (2.2–3.2 mmol g⁻¹) indicated that the HAs have the capacity to be loaded with 12–18% Fe(II), comparable to the iron content of previously reported Fe fertilizers that employ HAs from other sources (2–17%). The Fe(II)-binding capacities were positively correlated with the content of phenolic hydroxyl groups. In addition, the positive correlation between Fe(II)-binding capacity and vanillyl moieties in the HAs indicates that 3,4-dihydroxybenzene and/or benzoic acid derivatives also serve as Fe(II) binding sites.

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The destructive adsorption of trifluoromethane (HFC-23) and chlorodifluoromethane (HCFC-22) with CaO powder under air-flow was investigated. CaO pretreated at 873 K exhibited a high conversion potential (100% HFC-23 conversion over 2.5 h) at 873 K under HFC-23 (1 mol%)/air-flow. In the case of 100% HFC-23 conversion, the main gaseous products were CO₂, H₂O, and CO, and no fluorinated product was formed. On the other hand, CaO powder showed moderate potential for the destructive adsorption of HCFC-22 resulting in the production of CO, CO₂, H₂O, CaClF, and CaF₂. For the destructive adsorption of the HFC-23/HCFC-22 binary mixture, it was found that the presence of HCFC-22 retards the reaction of the HFC-23 molecule with CaCO₃, which is formed during the reaction. It was concluded from the results that high purity CaF₂ could be produced when only HFC-23 or the HFC-23/HCFC-22 (=9 : 1) binary mixture was fed into a CaO powder bed at 773 K under air-flow.

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