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)

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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A novel technique using a swirl-flow was developed to obtain a high throughput of dispersed phase flux in membrane emulsification. Shirasu porous glass (SPG) was used as a microporous membrane, methyl laurate was used as dispersed oil phase, and sodium dodecyl sulfate (SDS) was used as an emulsifier. The SPG membrane was a tubular membrane with inner diameter, length, and pore size of 9 × 10⁻³ m, 1.5 × 10⁻¹ m, and 5.2 μm, respectively. The continuous phase (water) was introduced into the inner space of the tubular membrane through an inlet tangential to the membrane axis to create swirl-flow. The swirl-flow velocity ranged from 0.85 to 5.4 m s⁻¹, and the dispersed phase flux ranged from 0.3 to 3 m³ m⁻² h⁻¹. Size-controlled droplets devoid of satellite droplets were produced at specific swirling velocities, and the droplet size dispersal coefficient was between 0.45 and 0.64. The oil-phase-to-water-phase volume ratio reached a value of 0.4 after a single passage through the membrane module. The mean droplet diameter was about four times the membrane pore diameter, and was hardly influenced by the dispersed phase flux and the continuous phase swirling velocity.
Swirl-flow membrane emulsification helped achieve extremely high throughput of the dispersed-phase flux and a stable emulsion was obtained.

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The formation of non-agglomerated titania particles by oxidation of titanium-tetra-isopropoxide (TTIP) has been studied in a methane/oxygen coflow diffusion-flame reactor. A change in the proportion of virtually non-agglomerated particles in TEM images was observed using a rapid cooling of the entire flame aerosol with a blow of cold Ar quenching gas and supercooling in a Laval nozzle placed above the flame. The proportion of non-agglomerates was 25% for TiO₂ particles produced without any cooling steps. When the quenching gas of 25 L/min Ar cooled at −70°C blew on the tip of the flame, the proportion of non-agglomerates was 70%. When the flame aerosol was supercooled in the Laval nozzle after blowing −70°C Ar quenching gas, a decrease in the aerosol temperature was induced from approximately 1500 to 300°C in 0.9 ms and, as a result, the proportion of non-agglomerates was as large as 90%. It was found that the rapid cooling in the region of the flame tip is quite effective for preventing agglomeration.

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The single constant pressure filtration test for dilute colloidal dispersions has been newly developed for easily determining the pressure dependence of the permeability characteristics such as the average specific cake resistance. The method made use of the gradual variation of the effective pressure drop across the filter cake with time generated by using the filter medium with a high medium resistance. The correlations between the average specific cake resistance and the effective pressure were obtained from the flux decline data. The data of the flux decline behavior obtained for the various values of the slurry concentration, applied pressure and medium resistance were largely merged by the normalized form of the reciprocal filtration rate vs. the filtrate volume. The validity of the method was confirmed not only for slurries of bentonite, Hara-Gairome clay, and polymethyl methacrylate (PMMA), but also for nanoparticle colloids of bovine serum albumin (BSA) and silica sol.

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The sulfate and Al³⁺ in ettringite (Ca₆Al₂(SO₄)₃(OH)₁₂ · 26H₂O) can substitute for other oxyanions such as chromate ions (CrO₄²⁻) and cations such as Cr³⁺, respectively. Ettringite synthesis in the presence of CrO₄²⁻ or Cr³⁺ was attempted by adding solid Ca(OH)₂ to an Al₂(SO₄)₃ solution to examine the behavior of these chromium species during uptake by ettringite. By supplying chromate ions and a sufficient amount of OH to a Ca(OH)₂–Al₂(SO₄)₃ solution, CrO₄²⁻-substituted ettringite was obtained; however, the formation of SO₄²⁻ ettringite was dominant. By suspending ettringite in K₂CrO₄, CrO₄²⁻ ettringite was also obtained via the ion-exchange mechanism. In the case of the OH-deficient solution, in which weakly acidic CrO₃ was employed instead of K₂CrO₄, a mixture of amorphous Al(OH)₃ and gypsum was precipitated , and no ettringite was precipitated. On the other hand, Ca(OH)₂–Al₂(SO₄)₃–CrCl₃ solutions, which contained Cr³⁺, produced precipitable mixtures of gypsum, Ca(OH)₂, Al(OH)₃, and Cr(OH)₃. The co-precipitation of Cr(OH)₃ with other hydroxides such as Al(OH)₃ was more favored than the formation of Cr³⁺ ettringite. Simultaneous removal of CrO₄²⁻ and Cr³⁺ by Ca(OH)₂–Al₂(SO₄)₃ addition was demonstrated. Sedimentation properties such as the terminal velocity of settling down and particle size of the obtained precipitates were estimated.

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Human skills are very important for maintaining high operational efficiency in the chemical industry. It is difficult to quantitatively evaluate the presence of such skills in a staff member because of the intangible and ever-evolving nature of the skills. However, the level of skills required to maintain high standards in a chemical plant necessitates the quantitative measurement of human skills. This paper builds on the value of skills metric, which is used to quantify an individual's level of skills, to determine the effect of a change in personnel on a team's overall value of skills. The value of skills metric contains a weighting factor that reflects the suitability of a skill corresponding to the position of the staff member within the team structure and the time devoted to each skill. A second weighting factor reflects the staff member's position within the team and the effort required to carry out the duties involved. In this paper, we propose a procedure to adjust the second weighting factor.

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The production of molecular hydrogen (H₂) from water by hydrogenase of thermophilic cyanobacterium Synechococcus sp. strain H-1 has been studied by following the time courses of the hydrogen concentration in the gas-phase, cell mass concentration and cellular content of D-glucose in dark batch reactions at temperatures ranging from 313 to 333 K. An anaerobic, dark, NO₃⁻ starvation, neutral or alkaline pH and shaking condition was found to be a prerequisite for H₂ production. Strain H-1 could multiply and produce hydrogen at all temperatures studied. A linear relation between hydrogen production and glucose consumption was observed and the yield coefficient of hydrogen in terms of D-glucose consumption was 71, 115 and 146 at initial concentrations of cell mass of 0.75, 2.5 and 9.5 g · L⁻¹, respectively. The activation energies for the maximum specific rates of cell mass growth, D-glucose consumption and hydrogen production were found to be 62, 12.6 and 122 kJ · mol⁻¹, respectively. The maximum specific hydrogen production rate was found to be 0.09 μmol · mg-chl a⁻¹ · h⁻¹ at 328 K, which is comparable to that reported in non-nitrogen-fixing unicellular cyanobacteria. It is concluded that utilization of thermophilic Synechococcus sp. strain H-1 for hydrogen production is beneficial since the contamination risk of mesophilic bacteria is low.

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High dissolution rates provide better alkalinity that is important for sulphur dioxide (SO₂) absorption. Therefore the rate at which magnesite dissolves is very important in wet flue gas desulphurisation process (FGD). In this study, we investigated the use of ammonium compounds for enhancing the dissolution rate of magnesium-based compounds. The dissolution rates were determined by using the shrinking core model (SCM) with surface control, i.e, [1 − (1 − X)^1/3] = k_rt. The dissolution characteristics were investigated under the following conditions by using the pH-Stat method: temperature, 60°C; pH, 5; stirrer speed, 200 rpm; particle size 45 μm. The addition of ammonium compounds helps improve the dissolution rate of magnesium-based compounds. Upon the addition of 0.5 g of ammonium nitrate, the dissolution rate constants increased by 122%. The dissolution reaction conformed to the SCM, and chemical reaction control was the rate-controlling step.

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We evaluated a reaction process in which waste concrete was used to recover phosphorus from wastewater. We conducted experiments using various actual wastewater samples obtained by the sludge dewatering process at a sludge disposal plant. The removal ratios of orthophosphate ions from actual wastewater samples were higher than those in the case of model wastewater for which the initial concentrations of orthophosphate ions (131–161 mgP L⁻¹) were equal to those for the actual wastewater sample and the Ca/P ratio (approx. 5 g g⁻¹). This result indicates that the high concentration of calcium ions originally contained in the wastewater samples promotes the reaction of HAP. The novel phosphorus recovery process developed in this study, which is based on the use of waste concrete, has the potential to contribute to the inexpensive recycling of phosphorus resources.

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