Editor-in-Chief: Yoshiyuki Yamashita (Tokyo University of Agriculture and Technology) Associate Editors-in-Chiefs: Hiroyuki Honda (Nagoya University) Takao Tsukada (Tohoku University)
Editors Tomohiro Akiyama (Hokkaido University) Georges Belfort (Rensselaer Polytechnic Institute) Jun Fukai (Kyushu University) Yutaka Genchi (National Institute of Advanced Industrial Science and Technology (AIST)) Takayuki Hirai (Osaka University) Masahiko Hirao (The University of Tokyo) In-Beum Lee (Pohang University of Science and Technology (POSTEC)) Eiji Iritani (Nagoya University) Hideo Kameyama (Tokyo University of Agriculture and Technology) Masahiro Kino-oka (Osaka University) Toshinori Kojima (Seikei University) Shin Mukai (Hokkaido University) Akinori Muto (Okayama University) Nobuyoshi Nakagawa (Gunma University) Satoru Nishiyama (Kobe University) Hiroyasu Ogino (Osaka Prefecture University) Naoto Ohmura (Kobe University) Mitsuhiro Ohta (Muroran Institute of Technology) Hiroshi Ooshima (Osaka City University) Noriaki Sano (Kyoto University) Manabu Shimada (Hiroshima University) Masahiro Shishido (Yamagata University) Shigeki Takishima (Hiroshima University) Richard Lee Smith, Jr. (Tohoku University) Yoshifumi Tsuge (Kyushu University) Da-Ming Wang (National Taiwan University)
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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
This article proposes equations for calculating initial Antoine constants using normal boiling points. A genetic algorism method, which does not make use of partial difference values for convergent calculation, was used to calculate the Antoine constants for 1,025 compounds. The calculated Antoine constants for homologous components changed monotonically with the increase in the carbon number.
Turbulent-mixing-layer flows in a vertical channel with polymer additives and bubble injection were experimentally studied by particle image velocimetry (PIV). The transparent test section was 1.0 m long with a 0.04 m × 0.11 m cross section, and the main stream was split into two substreams by a specially designed splitter. The velocities on the low- and high-speed sides are 0.36 m/s and 1.4 m/s, respectively. The Reynolds number based on the velocity difference between the two streams and the vorticity thickness δ at the trailing edge of the splitter was 13,500 for the pure water mixing-layer flow. Aquesous (200 ppm) Polyacrylamide (PAM) solutions and pure water were used as the liquid phase, and gas bubbles with a 0.5% void fraction were injected into the mixing-layer containing polymer additives, from the center of the splitter end, to check the influence of polymer additives and bubbles on the turbulent structure and properties. The distribution of the turbulence properties changed more significantly for the mixing-layer in the polymer additive case than in the pure water case. In the latter case, the Reynolds shear stress (RSS) peak was less than that for the pure water case at the same downstream cross section, but the vorticity peak in the polymer additive case was larger than that in the pure water case in the region the mixing-layer developed (x < 5δ). However, upon bubble injection, the effect of the polymer additives was diminished.
The aim of the present study is to propose a scale-up factor for the mean drop diameter in internally circulated batch rotor–stator mixers. The total energy dissipation rate (εt) is used as the scale-up factor for the mean drop diameter. εt is calculated from the power number, flow number, rotational speed, number of rotor blades, and number of stator holes. Because it is difficult to measure the circulation flow rate of an internally circulated mixer directly, the flow rate of a production-scale mixer is estimated by measuring the time required for complete mixing—termed “mixing time”—and taking into account the power number of the production- and pilot-scale mixers and the flow number of the pilot-scale mixer. Our experimental results indicate that εt could influence the mean drop diameter. Theoretical verification suggests that εt includes information on the mixer configuration (rotor diameter, stator hole diameter, stator wall thickness, stator opening ratio, and gap width) and manufacturing conditions (operating time: t; rotational speed: N; and total product volume: V). Our results show that a decrease in the mean drop diameter is proportional to t, N4, and V−1. Further, we estimate the mean drop diameter of the production-scale mixer by performing a model product experiment with a pilot-scale mixer. The above results also indicate that the scale-up criteria for the mean drop diameter can be determined on the basis of εt and in terms of the operating time and not necessarily in terms of the geometric similarities between mixer configurations, a constant rotor tip speed, or a constant clearance between the rotor and stator.
Plating a Pd membrane on the outer surface of a porous stainless steel (PSS) tube facilitates rapid H2 permeation with an absolute selectivity; the permeation is based on the solution-diffusion transport mechanism. Reforming of carbon hydride is a well-known method of manufacturing H2. CH4 dry reforming is performed in a membrane reactor using a thin Pd membrane. In this reaction, chemisorbed CO2 is known to affect H2 permeation behavior. The effect on H2 permeation and membrane stability were investigated by performing a permeation test and by XPS. After H2 was permeated through the Pd membrane, CO2 was flowed over the membrane for 1 h, and H2 was once again permeated through the membrane. In the experiment, the temperatures were 623, 723, and 823 K, the differential pressure was 0.1 MPa, and the feed rate was 10 mL/min. CO2 was replaced by He and the experiment was performed under the same conditions. After the second H2 permeation, the H2 flux increased with the time and attained its original value. The time required to attain the original value was dependent on the gas and the temperature. In the case of the He flow, the time required was only 5 min and was independent of the temperature. On the other hands, in the case of the CO2 flow, the required times were 10 min and 25 min at 623 K and 723 K or 823 K, respectively. After the CO2 flow, the XPS spectra of the surface of the Pd membrane were measured. The spectra showed that PdO was formed on the Pd membrane by oxidation of the Pd surface. The PdO was formed by chemisorbed CO2, and the H2 permeability was degraded by PdO; however, PdO was easily reduced to Pd by the H2 flow. When the experiment involving CH4 dry reforming was performed in the Pd membrane reactor with conventional Pt-based catalysts and a sweep gas for 12 h at 873 K, the H2 flux, H2 selectivity, and H2 recovery were ca. 6 mL/min, 98% (calculated by excluding the sweep gas), and 80%, respectively.
Liquid–liquid mass transfer with ultrasound was investigated experimentally during the hydrolysis of n-amyl acetate. Power ultrasound is supposed to improve the yield and kinetics of such multiphase chemical reactions thanks to the mechanical effects of cavitation. Indeed, implosion of micro-bubbles at the vicinity of the liquid– liquid interface generates disruption of this surface, and enhances mixing in the liquid around the inclusion, thus improving mass transfer between the two phases. This effect has been demonstrated here on the hydrolysis of n-amyl acetate by sodium hydroxide, a rather slow reaction but influenced by mass transfer; the reaction is carried out in a glass jacketed reactor, 500 mL of volume, equipped with a Rushton turbine and a 20 kHz sonotrode dipping in the solution. The ester is initially pure in the organic dispersed phase, and sodium hydroxide has an initial concentration of 300 mol/m3; one of the products, pentanol partitions between the two phases and the sodium salt stays in the aqueous phase. The initial apparent reaction rate is measured from the record of the conductivity giving the concentration of alkali versus time. The reaction rate was always found to increase when ultrasound is superimposed to mechanical stirring (at 600 rpm), with a positive influence of input power (20 and 50 W). When varying initial concentration (300 and 600 mol/m3), temperature (36 and 45°C) and ultrasound emitter (sonotrode or cuphorn), the benefit of ultrasound over mechanical agitation was systematic. The only case of a weak influence of ultrasound was the sonication of a dense medium, containing 23% of organic phase and impeding the propagation of ultrasound.
A palladium membrane reactor has been applied as a promising chemical hydrogen carrier to recover the hydrogen from cyclohexane. However, it is found that increasing feed rate resulted in a larger deviation from the ideal analytical model assuming plug flow and isothermal conditions. This study, therefore, presents a CFD (computational fluid dynamics) model development, which takes into account the mass and heat transfer, and its validation for the dehydrogenation of cyclohexane in a shell-and-tube type of palladium membrane reactor. The CFD model clearly shows that the temperature and concentration distributions were formed both in the radial and axial directions. Simulation results with cyclohexane dehydrogenation were in good agreement with the experimental data. It is expected that the model developed in this study will be applicable to more complicated reactor design and analysis.
Macromonomers are convenient means for introducing a functional group to a produced polymer. Amphiphilic polymer particles having a 2-[p-(1,1,3,3-tetramethyl-butyl) phenoxy-polyethoxy] ethyl group are a good support of an immobilized enzyme for use in enzymatic reactions in an organic solvent. To synthesize the amphiphilic polymer particle, an amphiphilic methacrylic monomer (MAX-n) having a 2-[p-(1,1,3,3-tetramethyl-butyl) phenoxy-polyethoxy] ethyl group has been synthesized and polymerized. The radical polymerization kinetics of MAX-n in solution polymerization and seed polymerization were then studied. In solution copolymerization of styrene and MAX-n, when the number n of the ethylene oxide units is high, the steric hindrance of the side chain of MAX-n results in a low propagation rate constant and a high monomer reactivity ratio. In seed polymerization, using the kinetic parameter obtained in solution polymerization and the experimentally measured value of mass fraction of polymer at which the glass transition occurred, the time course of conversion of the seed copolymerization of MAX-n and styrene were simulated.
In industrial production, one usually wants to seek an optimal product recipe or operation condition; however, due to the possible or known presence of multiple local optima in an unknown system such as a newly developed fermentation process, one may need to find the best global solution via the global optimization approach. An effective-global optimizer of non-convex functions can be applied to an unknown system with constraints to reach the global optimum by obtaining the surrogate model experimentally. Nevertheless, large experiments are usually indispensable for achieving a defined target. In this work, a monitoring chart describing objective function values with respect to cluster centers of local and global minima (or maxima) is proposed to follow the development of the identified radial basis function (RBF) model which is based on the information gathering from experiments specially designed. Based on the monitoring chart, whether the region surrounding the global extreme is reached can be followed. The proposed optimizing algorithm to reach the global optimum in an unknown process consists of the following two steps. Initially, the experiments designed by the global optimizer (rbfSolve routine in TOMLAB/CGO) is conducted before the region surrounding the global extreme is reached. When the region of global extreme is approaching, additional-optimizing experiments designed by the identified RBF model are then carried out to accelerate the rate to achieve the global optimum. The performance of the optimizing algorithm and the monitoring chart on an unknown process with the constraints proposed in this work was evaluated through (a) a constrained multimodal function as a problem of finding the recipe for a newly developed product and (b) a feed-rate optimization of a fed-batch fermentation process as a problem in obtaining an optimal-feeding trajectory. One can conclude that the experimental approach for achieving global optimization of an unknown process with constraints via an RBF based method is achievable in limited experiments.
The water samples collected from two non water-flooded oil fields contained a variety of organic acids, sulfate-reducing bacteria (SRB) and little sulfate. Acetate and propionate were the major components of organic acids. Over 6 weeks of artificial souring experiment, a maximum of 3 mM of sulfide was produced when oil field water was mixed with seawater at 25°C. Propionate was completely consumed under soured conditions. This indicated that the propionate-consuming SRB underwent souring in this experiment. Significant cell growth was confirmed at 25°C with no relation to souring. The dominant SRB species were shifted from Desulfomicrobium thermophilum to Desulfobacter vibrioformis and uncultured Desulfobacter.
We have examined the effects of two different solvents on the reaction rates in acetylation of aniline. Diethylether and acetic acid were used as solvents, and the reaction rates using a microreactor were compared to those with the batch method. The reaction rate constants with the acetic acid solvent were larger than those with the diethylether solvent in both the microreactor and the batch method. Moreover, in acetic acid, we reduced the reaction time to about 1/14 using the microreactor. The reaction rates indicate that this reaction was nearly a reaction-controlled process with diethylether used as the solvent, while the reaction process was diffusion-controlled when acetic acid was used as the solvent. We have also performed quantum chemical calculations including solvent effects to understand the mechanism of the solvent effects on reaction rates in solutions. Acetic acid with the larger acceptor property gives more stability to the acetic acid ion species in the transition states. The calculated reaction rate was higher when using acetic acid as the solvent because the activation energy was smaller than that obtained with diethylether. The calculated dependence on the solvent effects is qualitatively in agreement with the experimental value with the use of a microreactor. Therefore, it can be concluded that changing the solvent used is an effective way to accelerate reaction rates.
The solubility and supersolubility of L-phenylalanine in aqueous solutions is firstly reported in this work. At temperatures from 273.15 to 343.15 K, both solubility and supersolubility in water generally increase with the temperature, and the average metastable zone width is about 8.3°C. At the temperature of 298.15 K, the solubility remarkably decreases with an increase in the concentration of ethanol, which indicates that ethanol can be used as an antisolvent for the precipitation and crystallization of L-phenylalanine. When sodium chloride is added to the solution, the solubility of L-phenylalanine increases with the concentration of sodium chloride.