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)
Noriaki Kubota (Iwate University (Professor Emeritus))
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)

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

The Instructions for Contributors and other information are available through our website (http://www.scej.org/jcej/).

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Isobaric vapor–liquid equilibria for the ethylbenzene + p-xylene system at 40.00, 66.66, and 93.32 kPa have been measured using a modified Rogalski–Malanowski equilibrium still. Parameters for the NRTL equation are determined from the experimental vapor–liquid equilibrium data. In addition, the number of columns and the reflux ratio needed for separation by distillation are estimated. The separation performance can be partially evaluated, even if the mixture is assumed to be an ideal solution. However, we find that the temperature distribution in the distillation column differs, and that consideration of the activity coefficients affects the selection of the feed location.

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The polymorphic solid-state transition of theophylline anhydrate from Form I (stable at high temperature) to Form II (stable at room temperature) was investigated. The effect of temperature on the transition was examined at room temperature, 40°C, and 80°C under dry conditions, but no transition was observed under these conditions even after one month. However, at high humidity and 80°C, the above mentioned transition was found to occur, and hence, humidity was concluded to be a major factor affecting the transition to Form II. In addition, the crystal surface was monitored during the transition by AFM. Significant changes in the surface morphology were observed only in the presence of moisture. The transition kinetics were analyzed by taking the effect of humidity into account. The transition was well consistent with the serial model which combined the first-order reaction model and penetration model.

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The permeability of various organic solvents through a composite dense nonporous membrane comprising a silicon polymer as the active layer was studied to elucidate the transport mechanism under steady-state conditions. The permeability was calculated from the difference in the parameters of the solvent and the membrane polymer, |δ₁ – δ₂|, and the molecular weight (size) of the solvent, M₂; |δ₁ – δ₂| and M₂ would correspond to the solubility and diffusivity, respectively. Generally, the permeability of the different groups of common solvents classified on the bases of their molecular sizes tended to increase with a decrease in |δ₁ – δ₂|. However, the M₂ values of the alkane solvents were inversely proportional to their permeabilities. For a more detailed analysis of the transport mechanism, the regular solution model was used. The permeate flux of the solvent, ln (J₂), showed a linear dependence on the mole fraction of the solvent in the membrane phase, ln (X₂), and the square of the volume fraction of the solvent in the membrane polymer phase (degree of swelling), Φ₂². In the case of the common solvents, ln (J₂) showed a linear dependence on the product of the molar volume of the solvent (V₂) and the square of the solubility parameter difference (δ₁ – δ₂)² at constant pressure and temperature. In the case of the alkane solvents, a good correlation was observed between ln (J₂) and V₂, as the (δ₁ – δ₂)² values were numerically around unity. These results agreed with the conclusions drawn from studies performed using the solution-diffusion model. Thus, this new approach is expected to help in the accurate elucidates of the mechanism of transport of a non aqueous liquid through a composite dense nonporous membrane.

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The effect of static mixer internals on the hydrodynamic properties and the axial gas mixing characteristics has been determined in a circulating fluidized bed riser of FCC catalysts. Two types of static mixer are used with the variation of superficial gas velocity and solid circulation rate. With the static mixer in the riser, the axial solid holdup is much higher than that without the static mixer and the bottom acceleration length is shortened. The axial gas dispersion coefficients in the riser decrease with increasing solid circulation rate with the R–R configuration static mixer.

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An overall mathematical model is developed for estimating the number of lactide bubbles nucleated during the post-treatment step in polylactic acid (PLA) production. After PLA polymerization, residual unreacted lactide must be removed. The proposed model is used to determine the appropriate temperature for the lactide removal and is composed of three sub-models for surface tension, partial vapor pressure, and heterogeneous nucleation rate, which are expressed as functions of temperature. Visual observation experiments on lacttide bubble formation in PLA are conducted to compare the values estimated using the overall mathematical model with the experimental data. The surface tension is confirmed to be proportional to the –3.7th power of the absolute temperature in our experiments and to the –4th power of the temperature in the surface tension sub-model. The partial vapor pressure of the lactide in the molten PLA is proportional to its molar concentration, both in the experiments and the partial vapor pressure sub-model. The numbers of bubbles observed in our experiments are in good agreement with those estimated using the overall mathematical model.

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Unpredicted and unmeasured disturbances impose practical difficulties on the identification of discrete multiple-input/multiple-output parametric models from plant tests. A proper solution to such difficulties is not yet available. This article establishes an identification method based on Laguerre models with adjustable time-scaling factors. A linear regression equation is derived to incorporate the terms concerning initial states as well as disturbances occurring before and after the start of the identification test. The resulting least-squares estimator of the Laguerre coefficients is thus employed to develop process and disturbance models efficiently and accurately. The idea of augmented order is introduced to account for distinct load dynamics. To improve identification under deterministic disturbances, two error criteria are developed to infer the proper values of the time-scaling factor, the load entering time, and process time delays. In the presence of a stochastic disturbance, another error criterion is presented to determine the time-scaling factor that rejects the most deteriorating effect of the stochastic disturbance on parameter estimation. It is demonstrated that the proposed method is reliable against multifarious characteristics of deterministic and stochastic disturbances.

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Corn grains are pulverized by steam explosion after 40 min cooking at 533 K, and the products are further hydrolyzed under hydrothermal conditions. Residual solids consisting of particles having average diameter of 89 μm are obtained by steam explosion, and about 50–60 wt%(C/C) on carbon weight basis of initial sample is converted into water soluble (WS) components. The steam exploded products are further hydrothermally degraded in a small batch reactor at 453 to 493 K. The yields of WS components are almost unchanged with time at 453 and 473 K, but the molecular weights significantly decrease to lower than 1000.

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Micron-sized SrSO₄ particles having mono-dispersed/narrow distributions have been produced with a double-jet semi-batch reactive crystallizer. Slow molar feedings over a short time maintained proper supersaturation levels and result in narrow distributions due to the prevention of agglomeration growth of small primary precipitates. Furthermore, polyethylenimine (PEI) is a suitable growth/agglomeration inhibitor for sulfate precipitation, e.g., SrSO₄ and PbSO₄, and effectively reduced particle sizes leading to single-micron products. Besides feeding conditions, in the present work, the influence of PEI dosage on crystal size distributions (CSDs) is investigated. The controlled double-jet feeding using a polyelectrolyte additive such as PEI will be a powerful methodology to obtain agglomeration-free uniform micro-powders as a final solid product.

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A controlled double-jet reactive crystallization technique using a PEI (polyethylenimine) additive has been conducted to produce agglomeration-free micro-particles of SrSO₄ with narrow and mono-dispersed size distributions. PEI successfully inhibits rapid/continuous nucleation due to a complexation with strontium ions before nucleation occurs, and enables realization of perfect separation of nucleation and growth. Our idea to obtain fine particles with desired size distributions will introduce a new potential for contributing to enhance high-valued material properties.

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The depolymerization behavior of poly(ethylene terephthalate) (PET) to terephthalic acid (TPA) and ethylene glycol (EG) in high-temperature liquid water is examined in a batch reactor. PET is completely depolymerized in water for 10 min at 573 K. The total energy to obtain TPA and EG from a continuous PET depolymerization process with high-temperature liquid water is estimated.

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