Editor-in-Chief
Manabu Shimada (Hiroshima University)

Associate Editor-in-Chiefs
Masahiro Shishido (Yamagata University)
Ken-Ichiro Sotowa (The University of Tokushima)

Editors
Choji Fukuhara (Shizuoka University)
Toshitaka Funazukuri (Chuo University)
Yoshihiro Hashimoto (Nagoya Institute of Technology)
Shunji Homma (Saitama University)
Jun-ichi Horiuchi (Kyoto Institute of Technology)
Yoshinori Itaya (Gifu University)
Masashi Iwata (Osaka Prefecture University)
Noriho Kamiya (Kyushu University)
In-Beum Lee (Pohang University of Science and Technology (POSTEC))
Kouji Maeda (University of Hyogo)
Hideyuki Matsumoto (National Institute of Advanced Industrial Science and Technology (AIST))
Michiaki Matsumoto (Doshisha University)
Nobuyoshi Nakagawa (Gunma University)
Tsuguhiko Nakagawa (Okayama Prefectural University)
Yasuya Nakayama (Kyushu University)
Masaru Noda (Fukuoka University)
Mikihiro Nomura (Shibaura Institute of Technology)
Eika W. Qian (Tokyo University of Agriculture and Technology)
Yuji Sakai (Kogakuin University)
Noriaki Sano (Kyoto University)
Naomi Shibasaki-Kitakawa (Tohoku University)
Hiroshi Suzuki (Kobe University)
Nobuhide Takahashi (Shinshu University)
Kazuhiro Takeda (Shizuoka University)
Shigeki Takishima (Hiroshima University)
Yoshifumi Tsuge (Kyushu University)
Tomoya Tsuji (Nihon University)
Shigeyuki Uemiya (Gifu University)
Da-Ming Wang (National Taiwan University)
Takayuki Watanabe (Kyushu University)
Takuji Yamamoto (University of Hyogo)
Tetsuya Yamamoto (Nagoya University)
Masahiro Yoshida (Kagoshima University)
Yasuo Yoshimi (Shibaura Institute of 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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Most previous experimental investigations of two-dimensional (2D) granular column collapses have been conducted using three-dimensional (3D) granular materials in narrow horizontal channels (i.e., quasi-2D condition). Our recent research on 2D granular column collapses by using 2D granular materials (i.e., aluminum rods) has revealed results that differ markedly from those reported in the literature. We assume a 2D column with an initial height of h₀ and initial width of d₀, a defined as their ratio (a=h₀/d₀), a final height of h_∞, and maximum run-out distance of d_∞. The experimental data suggest that for the low a regime (a≤0.65) the ratio of the final height to initial height is 1. However, for the high a regime (a≥0.65), the ratio of a to (d_∞−d₀)/d₀, h₀/h_∞, or d_∞/d₀ is expressed by power-law relations. In particular, the following power-function ratios (h₀/h_∞≈1.42a^2/3 and d_∞/d₀∼4.30a^0.72) are proposed for every a≥0.65. In contrast, the ratio (d_∞−d₀)/d₀≈3.25a^0.96 only holds for 0.65≤a≤1.5, whereas the ratio (d_∞−d₀)/d₀≈3.80a^0.73 holds for a≥1.5. In addition, the influence of ground contact surfaces (hard or soft beds) on the final run-out distance and destruction zone of the granular column under true 2D conditions is investigated.

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The studies on the gas–liquid mixing in an agitated vessel have been conducted by several investigators but have rarely been investigated for the mixing time of liquid in the laminar flow region. In this work, we tried to measure the mixing times and power consumptions in an aerated vessel agitated by a dual Rushton turbine, dual pitched paddle and single Maxblend at relatively low Reynolds numbers, where the isolated mixing regions were formed for dual impeller systems and poorly mixed regions for the Maxblend without gas dispersion. As a result, it was found that the mixing time was decreased drastically by the introduction of gas into the vessel for all impeller systems covered in this work, where the Maxblend shows the shortest mixing time and the smallest decrease in gassed power.

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A numerical study of a thermocapillary flow in a thin circular pool under zero and normal gravity conditions was carried out to investigate the effect of free surface shape on flow direction. We have previously reported that the direction of a thermocapillary flow in a circular water film under zero gravity was dependent on the shape of the film. In the present study, we also found that the direction of the thermocapillary flow in a water pool is dependent on free surface shape even under normal gravity. This finding shows that we can control the direction of the flow in the pool by changing its free surface shape by varying the volume ratio of the pool.

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Dissolution of a carbon dioxide (CO₂) bubble in the downward flow of water or glycerol-water solutions in a vertical pipe is measured by using an image processing method. Numerical predictions of bubble dissolution using a Sherwood number Sh correlation for a bubble in stagnant water, which was proposed in our previous study, are also carried out to examine its applicability to single bubbles in several fluid property systems. The correlation can predict the bubble dissolution well, during which large bubbles change from Taylor to small bubbles, not only in water but also in glycerol-water solutions. A small bubble in a 50 wt% solution predicted by using the correlation, however, dissolves slightly faster than the experiments in the diameter range of 5–8 mm. CO₂ concentration fields visualized by using laser-induced fluorescence show that this is due to the difference in wake structures in the stagnant liquid and in the downward flow, that is, vortex shedding with shape oscillation in the stagnant liquid enhances mass transfer from small bubbles; whereas the closed wake in the downward flow reduces the mass transfer rate. This, in turn, implies that the Sh correlation can give good predictions for long-term bubble dissolution in various stagnant liquids.

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The performance of the hollow fiber reverse osmosis module is analyzed using a membrane transport equation based on the theory of irreversible thermodynamics. Three membrane properties of the irreversible thermodynamics model are estimated by the curve-fitting method using experimental data from a mini-fiber module, while the mass transfer coefficient is quoted from the authors’ previous correlation equation. As a result, the membrane properties such as L_p and P_m show quite reasonable values in comparison with the A and B values of the Solution–Diffusion model, and the calculated result of the module model is in good agreement with the actual performance data. Finally, the meaning of the solute convective coefficient γ is discussed quantitatively.

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Severe defluidization occurs when a reaction that is accompanied by a decrease in gas volume is performed in a fluidized catalyst bed. Defluidization occurs because the gas velocity in the emulsion phase decreases to less than the minimum fluidization velocity. Because numerous useful industrial reactions involve a decrease in gas volume, the development of a method for rapid detection of defluidization is important for maintaining good fluidization. In this study, the inside of a column was visually observed during CO₂ hydrogenation in a fluidized bed. When the reaction rate was low, good fluidization was always observed. However, defluidization, such as channeling, occurred occasionally when the reaction rate was increased. These reaction conditions were classified as the defluidization region in this study. The time-change characteristics for the frequency of pressure drop fluctuations were studied using continuous wavelet transfer (CWT). Additionally, the autocorrelation function was used to determine the dominant frequency. Using these functions, the decrease in the dominant frequency and the periodicity of the pressure fluctuations were detected in the defluidization region, even when the bed was observed to be satisfactorily fluidized. On the other hand, the prediction of defluidization itself several seconds before it occurred proved difficult.

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Mordenite (MOR) membranes are membrane is one of the water permselective membranes that can remove water vapor from water/alcohol mixtures. A permeation mechanism through non-zeolitic pores (intercrystalline pathways) of MOR zeolite membranes was discussed using an alkaline treatment of the MOR membranes. The alkaline treatment was carried out at 70°C in 0.2 M of NaOH solution. Permeation properties were evaluated by single gas permeation of N₂, water/isopropyl alcohol (IPA) pervaporation (PV), and perm-porometer measurements. Between 0 and 30 min of the alkaline treatments, the IPA permeances were kept constant and the water permeances decreased with the length of the treatment periods, showing that the MOR membrane was densified by the treatment. Between 30 and 40 min of the treatments, N₂ and IPA permeances increased with increasing the treatment periods while water permeance were kept constant. The non-zeolitic pores were formed by the alkaline treatment. The water selectivity decreased after 40 min of the treatment. The size of the non-zeolitic pores was 0.9 nm after 62 min of the treatment. The water/IPA selectivity through the membranes decreased to 94 from 2800 because of the alkaline treatment. Thus, we concluded that the size of the water selective non-zeolitic pores is less than 0.9 nm.

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Vaporization of Pb and Zn-loaded model compounds has been carried out in a lab-scale rotary kiln reactor to clarify their condensation behavior upon flue gas cooling in both air-firing and oxy-fuel combustion modes. The influence of flue gas impurities including HCl, SO₂ and H₂O has been examined systematically. For the two metals existing separately in the reactor, namely in single mode, both preferentially condensed as chlorides in the presence of HCl, under air-firing and oxy-fuel conditions. SO₂ and steam in flue gas promote chloride into sulfide at high temperature. It was noticed that the deposition propensities of Pb and Zn vapors under the oxy-fuel condition of the single mode were slightly enhanced over the air-firing condition. This is due to the lower Lewis number of oxy-fuel combustion that is in favor of the formation of highly polydispersed fine particles. However, this discrepancy was diminished in the case where both metals co-existed as in the mixture mode in the reaction system. In the mixture mode from 700 to 400 K, the condensation fraction of either Pb or Zn was confirmed higher than that in the single mode, due to an enhanced heterogeneous nucleation of Zn vapors on PbSO₄ nuclei.

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A series of experiments were conducted to investigate the degradation efficiency and treatment cost of 17β-estradiol using coagulation, adsorption, and advanced oxidation processes. The results show that granular activated carbon (GAC) adsorption collocated Ultraviolet C (UVC)/H₂O₂ shows the best 17β-estradiol (E2) removal. The E2 concentration of effluent water cannot be detected by instrument after one hour reaction. GAC adsorption collocated Ultraviolet A (UVA)/TiO₂ after one hour reaction degraded 92% of E2. Adsorption plays the main role in the removal efficiency above. The ultraviolet light (UV)/H₂O₂ oxidation program requires the least cost and has the best removal rate compared with other single processes. In economic assessment, a unit gram of E2 could be removed for as low as 53 U.S. dollar cost. GAC adsorption collocated UVC/H₂O₂ could completely removal E2 in water. It costs 76 U.S. dollar to treat one gram E2. The studies provide important information about E2 degradation and compare the technical development for E2 removal. Most importantly, this study provides information of process efficiency and cost for industrial application to contribute to the removal of E2 and industrial application.

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The present study uses mechanochemical processing to alter the redox characteristics and low-temperature selective catalytic reduction (SCR) activity of vanadium oxide. The properties of the catalyst were studied using physicochemical analyses, including BET surface area measurements, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, H₂ temperature-programmed reduction (H₂-TPR), and UV/Vis diffuse reflectance spectroscopy (DRS). The prepared catalysts are named V/Ti, V/Ti-AM (attrition mill), V/Ti-BM (ball mill), and V/BM3 Ti (vanadium loaded after the TiO₂ ball mill). The activity of the catalyst prepared by ball milling was the best because of the increase in the amount of lattice oxygen and surface-adsorbed oxygen that could participate in the reaction. In addition, the amount of vanadium oxide per unit volume increased, as did those of V⁵⁺, metastable V⁴⁺, and V³⁺. Raman spectroscopy demonstrated that the catalyst had the structure of monomeric V=O in crystalline V₂O₅ upon increasing the ball mill time to 10 h. This change in the structure influenced the reduction characteristics of the catalyst and decreased the maximum reduction temperature in H₂-TPR. When the ball-milling process was applied to a catalyst prepared by the wet-impregnation method for a certain time, the redox character was improved, and the activity of SCR could be increased at low temperature.

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Here, the oscillatory behavior of Saccharomyces cerevisiae (baker’s yeast) was investigated during the operation of a continuous bioreactor as it is detrimental to the stability and productivity of such a system. An unstructured segregated model was employed to study this phenomenon. The mathematical model couples a biological cell population balance model (PBM), representing the dynamics of cell mass distribution, with the mass balance of the rate-limiting substrate. High resolution flux limiter finite volume schemes have been proposed for approximating model equations efficiently and accurately. Moreover, analytical solution of a simplified yeast cell PBM was derived and the accuracy of proposed numerical schemes was analyzed by comparing analytical and numerical solutions. Good agreements in results and error analysis proved the accuracy of the proposed numerical schemes. Finally, the Globally Linearizing Control (GLC) was used for obtaining the total cell mass per unit volume. The GLC damps oscillations in substrate concentration by controlling the total cell number per unit volume. The ability of this controller to stabilize the steady-state and periodic solutions was analyzed through numerical simulations.

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A series of Zirconium modified MnO_x/Attapulgite (aZr–Mn/ATP) catalysts were synthesized by sol–gel method and evaluated for their performance in the low-temperature NH₃-SCR of NO and resistance to sulfur dioxide (SO₂). It was found that the NO conversion of Mn/ATP catalyst significantly improved after adding Zr. Among the catalysts investigated, the 4%Zr–Mn/ATP catalyst exhibited the highest catalytic activity, 96% NO conversion at 200°C, almost 100% N₂ selectivity in the whole test temperature range and good resistance to SO₂. The properties of catalysts were characterized by XRD, FTIR spectra, SEM and N₂ adsorption. In the catalyst, ATP is the support which supplies high surface areas, manganese (Mn₃O₄ and MnO₂) as the main active component plays an important role for NO reduction and zirconium (ZrO₂) acts as the auxiliary catalyst which can improve the diffusion of Mn, boost the low-temperature reduction performance and enhance the N₂ selectivity of the catalyst.

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Templated crystallization at the air/solution interface has the potential to produce monodispersed crystalline particles. To produce monodispersed particles adequately, the number of nuclei at the air/solution interface should be enhanced; however, it is predicted that increasing the number of nuclei has a negative effect on the size distribution (CV value). The objective of this study was to investigate the relationship between the number of nuclei and the CV value in templated crystallization. The air/solution interface was generated under static and vibration conditions. The average nucleation density under the vibration condition was about four times greater than that under the static condition. Disturbing the air/solution interface had no significant effect on the CV value. The reason behind this is that a repulsive force existed between neighboring crystals as suggested by additional observational results.

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Environmental and health problems due to sulfur dioxide (SO₂) emission are serious issues in China. In this study, we developed a model to assess the total economic and environmental impact on an area subsequent to installation of desulfurization facilities. A model based on the number of new patients with respiratory illness in Shenyang City, China and the corresponding environmental SO₂ concentration was first constructed and subsequently integrated into an air diffusion model for SO₂. Changes in the SO₂ concentration and the number of patients were then simulated, and the effects of desulfurization by-products on salt-affected soil amelioration were assessed in a number of scenarios where desulfurization facilities were installed in combustion plants. From the data, it is projected that the introduction of a wet limestone–gypsum process in large plants, an integrated desulfurization and water-film dust collection process in medium- and small-scale plants, and coal bio-briquettes in households should result in SO₂ concentrations below the stipulated SO₂ limit for urban residential areas in China. Moreover, a large decrease in the number of new patients and in the total number of patients at the year-end was forecasted for the years following the introduction of these facilities. Additionally, the present findings indicate that amelioration of salt-affected soil using desulfurization by-products is a prospectively effective method for increasing corn and rice production for potential alleviation of food shortages in China.

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Three enhanced phosphorus removal processes, each with a sequencing batch reactor (SBR), one with a humus soil side-stream reactor, one with an anaerobic side-stream reactor, and one without a side stream reactor (used as a conventional SBR process), designated as HS-SBR, A-SBR, and C-SBR, respectively, were operated and compared for the treatment of municipal sewage in laboratory scale. Compared with the total phosphorus (TP) removal efficiency of 68.3% obtained in the C-SBR, the TP removal efficiency in the A-SBR was only 53.2%, while in the HS-SBR, it increased to 85.6%. This observation suggested that the anaerobic side-stream reactor repressed TP removal in the system, while the humus soil side-stream reactor improved the TP removal. The detailed biochemical microbial analysis showed that the anaerobic side-stream reactor inhibited the TP removal activity through the repression of the polyphosphate kinase activity in the A-SBR, while the humus soil side-stream reactor improved the TP removal through improving the growth of polyphosphate-accumulating organisms and the activity of polyphosphate kinase, and inhibiting the growth of glycogen accumulating organisms in the HS-SBR. It was further speculated that humus soil in the humus soil side-stream reactor influenced the metabolism of PAOs and GAOs in the SBR.

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Polyaspartic acid/diethylenetriamine (PASP/DETA) graft copolymer was synthesized by urea, maleic anhydride and diethylenetriamine and its performance was evaluated by the static scale inhibition method. Due to the intramolecular hydrogen bonds of the side chains, the seven-member heterocycles were formed in graft copolymers. The results showed that the graft copolymers possessed improved scale inhibition performance against Ca₃(PO₄)₂ compared with PASP. The scale inhibition efficiency was close to 100% against Ca₃(PO₄)₂ and CaCO₃, when the concentration of PASP/DETA was 15 mg/L and 6 mg/L, respectively. Meanwhile, its scale inhibition performance was studied in different solution pH and temperature. The CaCO₃ and Ca₃(PO₄)₂ crystal turned into irregular shapes with the introduction of PASP/DETA in the solution, which was observed by scanning electron microscopy.

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