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) 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))
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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
A two-dimensional lattice Boltzmann model is constructed to simulate the evaporation of a single droplet on a homogenous wetting substrate. An evaporation model is used in the simulation to describe the mass loss from the surface of the evaporating droplet. In addition, a partial wetting boundary condition is imposed on the lattice sites on the substrate surface to determine the wettability of the substrate. The evaporation of a single droplet in ambient vapor shows a linear decrease in the square of the droplet radius, which agrees well with the d2 law for an evaporating droplet. During the evaporation of a droplet on a hydrophobic substrate, the wetting diameter decreases while the contact angle remains constant. During the evaporation of a droplet on a hydrophilic substrate, the wetting diameter decreases while the contact angle remains almost constant when a partial wetting boundary condition is imposed. However, three stages of contact line motion are observed when the partial wetting boundary condition is modified to describe the dynamical change in the contact angle, and this observation agrees well with a previous study by other investigtors. In addition, internal fluid flows towards the contact line of the droplet in the pinning stage of the evaporation are discussed.
The effects of particle size (dp) and superficial gas velocity (Ug) on the transport disengaging height (TDH) of iron ore particles were determined for a fluidized bed (i.d.: 0.11 m; height: 2 m). The entrainment rates of iron ore particles in the size range 0.063–1.00 mm in the height direction of the bed were measured by using an isokinetic sampling probe, and they were used to determine the TDH for different values of dp and Ug. The entrainment rate decreases exponentially with an increase in the freeboard height and particle size but increases with the gas velocity. The TDH increases with the gas velocity, but the TDH values are much less than values predicted from correlations in previous studies. The effect of particle size on the TDH is more pronounced than the effect of gas velocity and therefore, the TDH can be predicted by considering Froude and Reynolds numbers.
Oscillatory zoning is a kind of spontaneous pattern of micrometer scale formed in a particle. Many studies have been performed in the field of geoscience for which several weeks were required for pattern formation. In this study, a drastic reduction of the pattern forming period has been realized such that the pattern forming dynamics may be applied to particle processing technology. The repetition of ion supply and the subsequent ripening enable the formation of a pattern in less than a few hours. The chemical composition in the cross section of a particle varied in an oscillatory manner with the spatial period of 102 nm–101 µm. This fine chemical structure was generated spontaneously without hazardous chemicals such as organic solvents and surfactants. The spatial periodicity and the compositional amplitude are controlled by the periods of the ion supply and the subsequent ripening, respectively.
Tyramine was polymerized by an enzymatic reaction with horseradish peroxidase, and the polymer was used in the recovery of precious metals from acidic media. The obtained poly(tyramine) was a macroporous aggregate of particles and had a molecular mass of 1700 Da. In HCl solution, platinum and palladium were selectively adsorbed to the amino group in poly(tyramine). Poly(tyramine) had an adsorption capacity of 0.65 mol/kg for platinum and 0.51 mol/kg for palladium in 5.0 mol/L HCl. These results demonstrate that this polymer could be applied to the treatment of wastewater containing precious metals.
In the process of electro-osmotic dewatering of a semi-solid sludge put between two plate-type electrodes placed above and below a sludge bed, the water content in part of the bed near the upper electrode opposite to a lower drainage surface is considerably reduced, resulting in electrically poor contact between the upper electrode and the bed being dewatered, and then an excessive increase in electrical contact resistance between them. This obviously obstructs the efficiency of electro-osmotic dewatering throughout the entire bed, and consequently, the continuation of the dewatering process becomes increasingly difficult. From the viewpoint of lowering the influence of increasing electrical contact resistance, the usage of an upper plate-type electrode, in which the area of such electrode is smaller than the cross-sectional area of the sludge bed, is regarded to be practical in improving electro-osmotically the performance of sludge dewatering. In this study, electro-osmotic dewatering is experimentally investigated by reducing the area of not only the upper electrode, but both the upper electrode and the lower one on the drainage surface, and compared with the same-area electrode as the cross-section of the bed. Thus, the influence of such electrode arrangements in reducing the area of the electrode(s) on the dewatering process in terms of water removal and electrical energy consumption is examined using calcium carbonate as solid particles for sludge conditioning. As a result, it has been found that the amount of removed water and electrical energy efficiency for water removal can be increased compared with the same-area electrode as the bed, except for the case of an excessively small electrode area.
Ca(OH)2–Al(OH)3 and CaCO3–Al(OH)3 mixtures with Ca/(Ca+Al) ratios in the range 0 to 1 were calcined in the temperature range 873–1673 K for studying the effect of the calcination temperature and Ca/(Ca+Al) ratio on the calcination products. XRD analysis showed that the mixtures with Ca/(Ca+Al) ratios in the range 0.68–0.83 and calcined around 1273 K gave lime (CaO) as the major product and mayenite (Ca12Al14O33), Ca9Al6O18, and Ca5Al6O14 as the minor products. These calcination products indicated that the efficiencies of the removal of chromate and borate from the solution were high. Upon immersing these calcination products in chromate and borate solutions, Ca4Al2CrO10·12H2O and Ca4Al2(HBO3)0.5(OH)13·6H2O were formed, respectively; the Ca/(Ca+Al) molar ratio in these compounds was 0.68, which was close to that in the raw mixtures. A Ca/(Ca+Al) ratio in the range 0.68–0.83 resulted in the optimum removal of chromate and borate from the solution. The Ca/(Ca+Al) ratio was more effective than these crystalline components in these calcination products. Further, Ca(B(OH)4)2·2H2O precipitated as a result of borate removal.
The accurate identification of the boundaries of the main flow regimes in fluidized beds is very important since the degrees of mixing and mass and heat transfer depend on the prevailing flow regime. Both the minimum fluidization velocity Umf (0.103 m·s−1) and the transition velocity Utrans (0.12 m·s−1) to bubbling fluidization regime have been successfully identified based on a newly developed maximum information entropy (IEmax) algorithm applied to gamma photon time series. The latter are recorded by means of gamma-ray densitometry scans performed in an air–polyethylene fluidized bed (0.438 m in ID) operated at ambient conditions. A comparison with the Kolmogorov entropy (KE) algorithm has found that the new approach yielded more accurate transition velocities. The value of Umf is also validated by means of the profiles of both bed pressure drop and bed height, respectively. It has been found, however, that these parameters are not capable of identifying the second transition velocity Utrans. It is demonstrated that the Umf value identified on the basis of IEmax is theoretically predictable. In the bubbling fluidization regime, a simple correlation between both the KE and IEmax values is developed.
In the chemical industry, a labor productivity index is often used to estimate production efficiency. This index is often taken as the ratio of the production return to the production staff number. In this form, the index implies that a reduction in the number of production staff leads to an improvement in labor productivity. However, such an approach can lead to accidents and industrial unrest at a plant. Consequently, this definition of the labor productivity index does not accurately reflect reality. This paper proposes an alternative index, which combines the production skills of the production staff, or the value of skills, with the labor productivity index, to provide a more accurate and realistic estimate. It is also shown that an improvement in production skills contributes to an increase in labor productivity. A case study, in the chemical industry, is used to demonstrate the validity of the proposed method.
Based on the polymerizing technique and its thermal equilibrium mechanism for polyvinyl chloride (PVC), soft-sensor modeling of PVC polymerizing production processes is important and necessary for stabilizing and optimizing the PVC polymerizing production process. According to the principle that multiple models can enhance the overall accuracy and robustness of a predicative model, a multi T–S fuzzy neural network soft-sensing model combining with fuzzy c-means (FCM) clustering algorithm is proposed to predict the conversion rate and velocity of vinyl chloride monomer (VCM) in the PVC polymerizing production process. Firstly, the principal component analysis (PCA) method is adopted to select the auxiliary variables of the soft-sensing model in order to reduce the model dimensionality. Then, a hybrid optimization algorithm utilizing the harmony search (HS) and least square method is proposed to optimize the structure parameters of the T–S fuzzy neural network. Ultimately, simulation results show that the proposed model can significantly enhance the predictive accuracy and robustness of the technical-and-economic indexes and satisfy the real-time control requirements of PVC polymerizing production process.
Flat glass is widely employed in many applications such as for buildings and commercial products. It is the product of a series of chemical processes. In order to raise the profitability of flat glass companies, various issues in the process should be considered. An important but unexplored issue is minimization of the waste generated by cutting the original large sized mother glass into multiple items of small size. The resulting problem is called a cutting stock problem and is an important issue because of its financial impact. The profitability of a glass company is thus dependent on developing efficient algorithms to solve this problem. Motivated by the practical needs, a heuristic algorithm for the cutting stock problem is proposed to minimize the waste of the glass bin while meeting demand. Several case studies from actual flat glass companies are presented to illustrate the applicability of the algorithm with some remarks.
Blockage diagnosis is indispensable to ensure that microreactors operate effectively and stably. In this paper, we propose a data-based blockage diagnosis method using pressure sensors that can identify two blockage locations in a microreactor. The method identifies these locations by comparing measured pressure distribution data with prepared pressure distribution data for a case of blockage occurrence. The data are calculated by computational fluid dynamic (CFD) simulation. To avoid a combinatorial explosion of CFD simulations for database construction, the proposed method identifies blocked locations from just pressure distribution data when a single channel is blocked. The proposed method is applied to the blockage diagnosis problems of a microreactor with ten microchannels. The results of CFD simulations show that the method can accurately identify two blockage locations using fewer pressure sensors than there are microchannels.
Polymorphism is an interesting property of crystalline substances and is of importance in pharmaceutical development. Studies were conducted to identify the most stable of the five polymorphic (one hydrate and four anhydrous) forms of the active pharmaceutical ingredient (API) E3210. Between the different polymorphs, the transformation mechanisms and thermodynamic stability relationships were complex. Forms A and B were further characterized by differential scanning calorimetry (DSC) at various heating rates and by powder X-ray diffractometry (PXRD; isothermal and temperature-controlled). Analysis by DSC revealed that Form A displayed a single and large endothermic melting peak. Form B displayed two small peaks, one endothermic peak and the other exothermic; the endothermic peak was an enantiotropically related reversible transformation from Form B to Form B′, and the exothermic peak was a monotropically related thermodynamically irreversible transformation from Form B′ to Form A. Thus, Forms B and B′ were enantiotropically related polymorphs, and both were monotropically related to Form A. Form A was the most stable polymorphic form and Form B was metastable.
Many studies have, in a general sense, paid a great deal of attention to university spin-offs in biotechnology or information technology. However, little attention has been given to university spin-offs in chemistry and chemical engineering. The present study discusses the business relationships between university spin-offs and manufacturers. Questionnaires were sent to the inventors of university spin-offs. The 82 replies were classified into four fields, (1) Chemistry, (2) Electronics, Machinery and Others, (3) Biotechnology and (4) Information Technology. Two university spin-offs were interviewed. The results show that there are differences between the spin-offs in Chemistry and those in other fields. University spin-offs in Chemistry tend not to receive investment from manufacturers, but do have joint funding with manufacturers. They also tend to support research and development (R&D) of their partner manufacturers and may not be as attractive as spin-offs in other fields to outside investors, such as venture capitalists. However, the open tendency of university spin-offs in Chemistry is essential to advance the R&D of many industries in Japan.