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 email@example.com
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 flow pattern and power number in a vessel depend on the geometrical parameters of the impeller and the stirred vessel. This paper discusses the influence of the blade pitch angle of a six-blade Rushton disc turbine on the flow and energy dissipation in horizontal and vertical stirred vessels. Measurements for the two types of stirred vessels (diameter: 240 mm) are carried out by experiments and numerical simulations using computational fluid dynamics (CFD). The difference in the mixing characteristics and energy dissipation in the two vessels is discussed. With an increase in the pitch angle, the power number and flow pattern change gradually in the horizontal vessel and sharply in the vertical vessel. The results of the present study can be used as reference data for industrial horizontal stirred tanks.
The granules used in powder compaction processes must have homogeneous morphology and the appropriate breaking strength. Hence, in order to control the morphology and breaking strength of granules, it becomes important to clarify their formation mechanisms. In the present study, the relationship between the morphology of spray-dried granules and drying conditions has been investigated by using numerical simulations. A simulation method for the drying of particulate suspensions has been developed by combining a distinct element method (DEM), which is used for analyzing particle behavior, with a constrained interpolation profile (CIP) method, which is used for analyzing gas–liquid multiphase flow. The particle motion and gas–liquid flow during the drying of droplet-suspended particulates are calculated at various air temperatures using this simulation method. A hollow granule is formed, and enlarges when the air temperature and drying rate are increased. When the drying rate is increased, particles begin to crust into a droplet surface early; moreover, the shrinkage of the crust is stopped earlier than under the condition of low drying rates. The gas–liquid interface then enters the crust. In this manner, a hollow granule is formed. We then perform simulations of the drying of a suspension droplet with different drying rate distributions on the droplet surface. A depression is formed at the granule surface at the part with low drying rate; in contrast, in the case of the part with the higher drying rate, the crust is formed rapidly and the gas–liquid interface begin to invade into the crust earlier. A capillary force arises and a liquid pressure decreases in the crust, and then the liquid flows according to the pressure gradient. Because particles are transferred with the liquid flow, the crust partially collapses inward, while depressions are formed in the granule.
A new ebulliometer to determine experimental VLE data, totally constructed by P. Susial, is reported. The equilibrium chamber, made of copper, presents some necessary modifications in comparison with the glass ebulliometer made by Casiano de Afonso. The new equipment belongs to those in which both phases are recirculated. In order to verify its reliability, the apparatus was tested with mixtures previously studied by various authors. VLE data for the methyl acetate + methanol binary system at 1.0, 3.0 and 7.0 bar were determined. The experimental data have been tested with the point-to-point test of Van Ness, applying the Fortran program of Fredenslund, and have shown to be consistent. In addition, the experimental results have been compared with those obtained from the UNIFAC (including different versions) and ASOG prediction models.
When ultrasound is irradiated in liquid, a local reaction field with high temperature and high pressure, which is called a hot spot due to cavitation, is formed. In order to enhance the performance of a sonoreactor, it was considered to improve the liquid flow by a propeller set in the sonoreactor. With the placement position, the revolution speed and the number of blades of the propeller varied at the same liquid height and power input, a decolorization reaction of iodine in the presence of disodium hydrogenphosphate in a starch solution has been carried out in order to examine the effect of the mixing on the sonochemical reaction. The mixing by the propeller made the intrinsic chemical reaction field larger and the sonochemical reaction faster. The reaction rate became faster with an increase in the revolution speed of the propeller. At the same placement position and revolution speed, the reaction rate was much faster for a propeller with more blades.
Methanolysis of a Jatropha curcas-waste food oil mixture that contained 1 wt% of free fatty acids was carried out in the presence of a KOH catalyst in a batch reactor at various methanol-to-oil molar ratios; the reaction temperature was varied from 25 to 60°C; the catalyst concentration was varied from 0.5 to 2.0 wt% of oil; the mixing speed was fixed at 900 rpm and the reaction time was 2 h. Samples were collected during the reaction time and analyzed by gas chromatography (GC) to determine the weight percentages of the reaction constituents on glycerol-free basis. The experiments revealed that the reaction conditions (mixing level, reaction temperature, catalyst concentration, and methanol-to-oil molar ratio) have a significant effect on the hydroxide catalyzed methanolysis reaction of the Jatropha curcas-waste food oil mixture. The conversion rate of the oil mixture and the methyl ester production rate increased with the mixing speed, reaction temperature, catalyst concentration and methanol-to-oil molar ratio. A second-order kinetic model with the reaction rate constants obtained in the experiment provided a satisfactory mechanism for the methanolysis reactions. The kinetic model was able to describe the experimental data, and the average relative average difference (RAD) was 4.7%. The simulation and experiments also indicated that although the methanolysis reaction consisted of three stepwise and reversible reactions, the forward reactions were the most important. Activation energy analysis showed that the methanolysis reactions of the Jatropha curcas-waste food oil mixture were sensitive to reaction temperature changes.
Dimethyl ether (DME) is a clean and efficient synthetic fuel with the potential to substitute liquefied petroleum gas (LPG) and diesel. From both the environmental and economic viewpoints, there is a strong preference to use biomass as the feedstock of synthetic fuels. In this study, state-of-the-art technologies were surveyed and a superstructure representation for the DME production process involving the use of biomass as a feedstock was investigated. Moreover, a mixed-integer nonlinear programming (MINLP) model was proposed for developing a DME production process based on biomass gasification. A combination of optimal technologies was adopted; detailed studies are presented to demonstrate the key features of the proposed superstructure.
A real-time monitoring and estimation method is proposed for managing facilities that store hazardous materials. It relies on optical sensor networks and neural networks trained for Gaussian dispersion model for the detection and analysis of hazardous (gas) releases. This method generates estimated values of the release rate, which provide the basis for the corresponding planning and response actions. While previous monitoring methodologies take less accurate assumed values for release rates, resulting in overestimation of hazards, the proposed method provides calculated values that are within acceptable differences from those estimated after intensive, time-consuming trials with commercial software like PHAST or TRACE. The proposed method does the efficient calculation of the extent of damage, in a shorter period of time, because it directly estimates the release rate with the given inputs, while the commercially available software takes a trial-and-error approach because of the absence of information on the leak size, which is difficult to get in real cases of accidents. It also produces relatively accurate estimation results even for releases of untrained materials. The results indicate that the proposed method can improve the accuracy and availability of information that is crucial to the success of emergency information systems.
Recently, Kansei (emotion) engineering has attracted interest in artifact design since it helps ensure customer-defined satisfaction in the current scenario of global competition and short product life cycles. Accordingly, intelligent decision-making through multiobjective optimization has been proposed as an efficient method for human-centered manufacturing. From this viewpoint, in this study, we apply a multiobjective optimization method referred to as MOON2R to an ill-posed problem that involves both qualitative and quantitative performance measures. Additionally, to facilitate the portability of the proposed method, especially in multidisciplinary decision-making environments, we implement the proposal algorithm in an Excel spreadsheet and validate the effectiveness of the method through a case study.
Micronized BaSO4 particles with a narrow size distribution were produced by using a double-jet reactive crystallizer. Polyethylenimine (PEI) acted as a growth/agglomeration inhibitor at a high PEI dosage, hence the particle size and size distribution width decreased, and BaSO4 crystals with the desired qualities were obtained. Similar results were obtained in previous studies in which of SrSO4 and PbSO4. We believe that our method, which involves the use of PEI, can be employed for the production of various inorganic sulfates in which the particles have a monodisperse size distribution.
The combustion possibility of Indonesia KBB coal as a pulverized fuel for a thermal power plant was studied with a thermogravimetric analysis (TGA), drop tube furnace (DTF) and ignition temperature (IT) tester. TGA results showed that combustion patterns of coal samples were divided into devolatilization and oxidation reactions, and the fixed carbon contained with minor content in high moisture KBB coal (HM KBB) was quickly burned at a lower temperature than that of bituminous C&A coal (Design C&A). The linear regression for the Arrhenius plot to the experimental data is very good, and activation energies for overall combustion of Design C&A and HM KBB are 63.19 and 81.89 kJ/mol, respectively. It was derived that activation energies of dry KBB coal (Dry KBB) produced through drying of HM KBB and its mixture (Dry KBB Mixture) are 79.82 and 61.66 kJ/mol in reciprocal proportion to specific surface area. Test results show that the volatile content contained in coal samples except for HM KBB with the lowest surface area significantly improved the combustion reactivity. The conversion behavior of the coals observed in DTF was similar to that reflected in TGA. DTF studies showed that the combustion of Dry KBB Mixture was also completed at a residence time of around 1 s and set temperature range of 1,200°C similar to commercial coal fired plant. Although Dry KBB has the highest conversion of the four coals, it was not appropriate as a single pulverized fuel of coal fired plant because its initial deformation (IDT) and ignition temperatures of about 1,088 and 198°C, respectively, were too low to cause slagging in boiler, and firing at the pulverizer. The high IDT of Dry KBB Mixture ash with minimum of 1,250°C is not expected to be associated with slagging and fouling in pulverized coal fired systems. The liability of spontaneous combustion of coal samples was increased with increasing the moisture and volatile contents whereas that of Dry KBB was the highest due to the high surface area. It was, therefore, proposed that the combustion of mixtures of Dry KBB with Design C&A was the most appropriate for the prevention of slagging and spontaneous combustion in pulverized coal fired boilers and has excellent combustion efficiency.
The condensation behaviors of Zn, Cu, and Pb in the cooling section of an incineration plant were investigated under simulated conditions in HCl/SO2/H2O system. By adjusting the composition of the reacting gas, the effect of the S/Cl ratio and H2O on the condensation of the heavy metals was evaluated. In addition, single-metal and multi-metal (Pb/Cu/Zn) condensation were compared to investigate the influence of heterogeneous nucleation on heavy metal deposition. Experimental results showed when PbSO4 was deposited firstly could induce the deposition of Cu and Zn on its surface through heterogeneous nucleation. As a result, the deposition of PbSO4 promoted the condensation of Zn and Cu at high temperatures, and an increase in SO2 enhanced the heterogeneous nucleation (due to the increase in PbSO4) to an extent comparable to that accompanying an increase in H2O according to the overall reaction 2MCl2+2SO2+O2+2H2O → 2MSO4+4HCl.
A bench scale unit (2 m3N/h) for removing CO2 from flue gas was operated. Based on a chemical absorption/regeneration process with aqueous monoethanolamine (MEA) solution, we have evaluated the energy requirement for regeneration and degree of CO2 removal as a function of reboiler temperature, MEA concentration, CO2 concentration in the flue gas and ratio of the flow rate of liquid and flue gas. For verification of the experimental results from the bench scale CO2 capture unit, we have also calculated the regeneration energy by the summation of the reaction enthalpy of CO2, the sensible heat and the heat of vaporization of MEA solution and have compared these results with those of bench scale tests. It was observed that the regeneration energy using a 30 wt% MEA solution was 4.29 GJ/ton CO2 (experiment) and 4.55 GJ/ton CO2 (estimation), respectively. Also, the degree of CO2 removal increases with an increase in reboiler temperature and ratio of the flow rate of liquid and flue gas, while CO2 regeneration energy decreases with an increase in MEA concentration and CO2 concentration in the flue gas.