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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In this paper, we report the density of a solvent system containing propylene glycol (PG)+2-amino-2-methyl-1-propanol (AMP)+water at 303.13, 308.15, and 313.15 K and different PG mole fractions ranging 0.02 to 0.60. The data fit in the Redlich–Kister equation for excess molar volume. We also report a new set of physical solubility data for CO₂ in PG+AMP+H₂O, estimated from N₂O solubility (at the same range of molar compositions and temperatures) by way of the so-called N₂O analogy, a method which has been used and proven to give reliable estimate of CO₂ solubility in previous studies. The measured solubility data for N₂O in the solvent system made a good fit with the differential Henry’s law coefficient model.

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A simple method for estimating the Wilson parameters from pure component properties alone previously proposed has been adopted to predict the vapor–liquid equilibria of binary systems containing carboxylic acids such as acetic acid. Carboxylic acid vapors are characterized by the presence of large amounts of dimers. The binary mixtures of non-associating substance+carboxylic acid and carboxylic acid+carboxylic acid have been studied. The prediction performances obtained are examined and discussed.

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The distributions of local Sauter mean bubble size, gas void fraction, and interfacial area in a standard stirred tank equipped with a half elliptical blade disk turbine (HEDT) have been investigated at different gas flow rates using photography techniques. In the identification of bubble size, the liquid phase is dyed with fluorescent rhodamine to make the gas–liquid interfaces clearly visible under a laser sheet. An image processing algorithm is used to analyze the bubbles interface, and the algorithm’s reliability has been validated by comparing with manual counting method. The image accuracy is about 0.05 mm, and the minimum identifiable bubble is 0.45 mm. The investigation of the distributions of void fraction is based on a “depth field” method through a calibration experiment. Results show that the local void fraction and interfacial area distributions are similar, and the maximum values are located below the impeller. The tank-averaged Sauter bubble size increases slightly with increasing ventilation, and the increase in void fraction with increasing ventilation is nearly in the same proportions.

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To predict the sieving rate with high accuracy, passage probability models were proposed for undersized particles passing through (1) the vibrated particle bed, (2) the boundary between the oversized particles and the sieve surface, and (3) the sieve openings. The probability of undersized particles passing through a vibrated particle bed depends on the porosity of the bed; the probability was determined by considering the estimated porosity of the bed and the diameter of the particles constituting the bed. The sieve openings were partly covered by oversized particles, and undersized particles could reach these openings only when the gap between the oversized particles and the sieve surface (the boundary) became larger than the undersized particle diameter; the probability of undersized particles passing through the boundary was also derived. Gaudin’s probability was applied to the probability of undersized particles passing through sieve openings without a boundary. The sieving rate calculated by using the proposed estimation equation based on the three probability models corresponded closely to the experimental results, and thus, the sieving rate was predicted with high accuracy.

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We report an investigation into the effectiveness of a hybrid membrane bioreactor (MBR) composed of an anoxic, non-woven fabric filter (NWFF)-aerobic reactor and an integrative microfilter (MF) with simultaneous dosing of a coagulant. Preliminary jar tests were conducted with four different additives (aluminum sulfate, FeCl₃, FeSO₄, and PACl) to observe the effects induced by changes in pH, alkalinity, soluble chemical oxygen demand (SCOD), and PO₄³-P of the permeate on the NWFF-aerobic reactor. The use of aluminum sulfate improved performance as it related to SCOD and phosphorus removal in the amounts of 2.1 mol aluminum sulfate/mol PO₄³-P. In the hybrid MBR, the average total phosphorus removal efficiency of the entire system was as high as 79% with continuous addition of 100 mg/L aluminum sulfate. Three-dimensional fluorescence excitation-emission matrix (F-EEM) spectroscopy of the liquid samples from the MBR indicated the presence of humic-like organic matter, which was regarded as primary aromatic organics.

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Several activated carbons (ACs) were prepared from bamboo chips (BCs) with ZnCl₂ activation. The influences of the specific surface area and pore size distribution on the adsorption of dyes, such as 2-naphthol (2-N, MW: 144), methylene blue (MB, MW: 320), and congo red (CR, MW: 697) were investigated using each prepared AC. AC with different mesopore volumes and same surface chemistry could be prepared by ZnCl₂ activation. In particular, the sample activated with the ZnCl₂/BC mass ratio of 6 (Z6) showed a remarkable increase in the specific surface area and mesopore volume to values as high as 2050 m²/g and 1.1 cm³/g, respectively. The results of all adsorption experiments revealed that MB and CR were adsorbed on mesoporous AC more efficiently than on microporous AC, and no CR adsorption onto microporous AC was observed. Further, the adsorbed amount of 2-N, with small molecule size, was dependent on the specific surface area rather than mesopore volume.

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An approximate explicit formula for the enhancement factor in the case of irreversible (m,n)th-order gas–liquid reactions is derived. The formula is applicable in both the slow- and fast-reaction regimes. The accuracy of the formula has been tested by comparing it with the exact numerical solution of the film model. The comparison is made over wide ranges of the Hatta number, ratio of bulk liquid concentration to interfacial concentration of the gaseous reactant, and other parameters of the reaction system. The overall mean percentage deviation of the approximate formula is within 5% for m=1 and integer orders n in the range [1,3], while the deviation is within 19% for n=1 and integer orders m in the range [1,3].

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This study covered the introduction of simultaneous heat and mass exchanger networks. A commercial simulator module was developed as a user interface to retrieve supplemental data from the ASPEN PLUS simulator and to communicate with the optimizer, the general algebraic modeling system. The model formulation for the network could be classified in the class of mixed-integer nonlinear programming optimization models. All the available constraints for the model were linear, but the target for the minimum total annual cost, as the objective function of the model, was nonlinear. Therefore, the operating costs for mass separation agents and external hot and cold utilities, along with the annualized equipment costs for heat and mass exchangers, could be minimized simultaneously. Three case studies from the literature were used to illustrate the proposed procedure. From the results, the synthesis of the combined heat and mass exchanger networks can satisfy the heat and mass balance of the process and obtain the lowest total annual cost for the network.

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A Ni–Ag catalyst was prepared and evaluated for the reforming of methane with CO₂. The experiments were carried out under atmospheric conditions using a 17 : 17 : 2 CH₄/CO₂/N₂ gas mixture at a total flow rate of 36 mL min⁻¹ and a reaction temperature of 500–700°C. The stability of the catalyst was tested for 540 min. This study focuses on an experimental investigation of the effect of the addition of an Ag promoter to a 5 wt%Ni/γ-Al₂O₃ support. The performance of the developed catalyst was quantified by determining the CO₂ and CH₄ conversion, synthesis gas ratio (H₂/CO), and stability. The spent and fresh catalysts were characterized by BET, TGA, and XRD. Time-on-stream stability and TGA tests of the catalysts showed that increasing Ag content led to decreased carbon formation and activity. By adding 5 wt%Ag at 700°C, the conversion of methane decreased from 81.4 to 62.5% while coke formation decreased from 7.8 to 0.3 wt%.

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The Chemical Gas Turbine (ChGT) system, which has been proposed as a novel system of energy generation, comprises two gas turbines and a steam turbine in a cascade configuration. The combustion in the first gas turbine is performed under a fuel-rich condition, while that in the second one is conducted using the exhaust gas from the first gas turbine as a fuel, because it contains combustible components such as H₂ and CO. In the present study, the thermal efficiency of the ChGT system to which a dimethyl ether (DME) combustion system was applied has been calculated based on thermodynamic analysis to identify the potential of DME as a fuel in the ChGT system. These results are compared with those of CH₄ combustion and a conventional combined turbine cycle. In addition, the characteristics of DME combustion, especially under a fuel-rich condition, are investigated empirically.

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Wastewater treatment processes are typically complex dynamic processes. They are also energy-intensive processes. Using a more accurate control method is an effective solution to reduce the running cost of an entire wastewater treatment system. In this paper, a fuzzy sliding control scheme is proposed to control the aeration process of a sequencing batch reactor wastewater treatment process. It controls the aeration process by regulating the oxygen transmission coefficient according to the dissolved-oxygen index. Simulation results show that the proposed control scheme can deliver effective control.

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This study investigates the removal mechanism of arsenate, i.e., As(V), by coprecipitation with aluminum hydroxide in solution at pH 5. Both the filtrates and precipitates were analyzed. The removal mechanisms of As(V) were investigated by constructing sorption isotherms and by analyses of X-ray diffraction (XRD) patterns, zeta potentials, and Fourier-transform infrared (FT-IR) spectra. The sorption isotherms showed Brunauer–Emmett–Teller (BET) behavior. The sorption densities showed a rapid uniform increase when the initial As/Al solution molar ratio was more than 1.5. This suggests two sorption mechanisms of As(V), namely surface complexation and three-dimensional uptake, which were dependent on the initial As/Al molar ratio. It is important to note that the As(V) and Al(III) concentrations were unable to reach the thermodynamic solubility product of aluminum arsenate in the bulk solution. The three-dimensional uptake was therefore estimated to be not bulk precipitation but surface precipitation of aluminum arsenate. Surface precipitation, generation of a new surface phase, is known to be derived from surface complexes. XRD, zeta potential, and FT-IR analyses of the precipitates for each As/Al molar ratio confirmed that As(V) was predominantly removed by the adsorption of the As(V) oxyanions to the aluminum hydroxide surface when the initial As/Al molar ratio was less than 1.5. At an initial As/Al molar ratio greater than 1.5 at pH 5, As(V) was removed mostly by surface precipitation, evidently by poorly crystalline aluminum arsenate on the surface. This sorption as surface precipitation is a phenomenon specific to the coprecipitation process.

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