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Volume 34 (2008)
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- Issue 5 Pages 493-
- Issue 4 Pages 415-
- Issue 3 Pages 313-
- Issue 2 Pages 205-
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Volume 34, Issue 4
Displaying 1-13 of 13 articles from this issue
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Hitoshi Kosuge, Naoto Ohmura2008 Volume 34 Issue 4 Pages 415-416
Published: July 20, 2008
Released on J-STAGE: August 01, 2008
JOURNAL RESTRICTED ACCESSThe Outstanding Paper Award Subcommittee has assessed the 93 papers published in 2007 (vol. 33), and the editorial board finally selected the following two papers for Kagaku Kogaku Ronbunshu Paper Awards of 2007: “An Investigation of Primary Particle Growth and Aggregate Formation of Soot Using a Numerical Model Considering the Sintering of Primary Particles,” and “A Method for Setting Buffer Times between Batches with Uncertain Processing Times.”View full abstractDownload PDF (144K)
Transport Phenomena and Fluid Engineering
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Shuichi Iwata, Yusuke Yamada, Shogo Komori, Hideki MoriArticle type: Research Papers
Subject area: Transport Phenomena and Fluid Engineering
2008 Volume 34 Issue 4 Pages 417-423
Published: July 20, 2008
Released on J-STAGE: August 01, 2008
JOURNAL RESTRICTED ACCESSExperimental measurement of the local velocity profile around a small bubble in a pressure-oscillating field obtained by the particle tracking velocimetry was performed to study the mechanism of the pressure-oscillating defoaming process. Measurement of the movement of distributed pigments per unit time around the bubble and change in the bubble diameter over a cyclic period of pressure-oscillating enable us to measure the velocity gradient of the fluid directly around the bubble. A high density video camera in conjunction with strobe lighting was used to record the vibrating bubble, because the applied oscillation frequency was much higher than the frame speed of commercial video cameras. It was found that observed radial velocities were not the same along the bubble surface; radial velocities were high in the lower region of the bubble than the upper region, because the fluid in upper region was surrounded by the rigid cell wall and the fluid was pressed from the downside through a sheet of rubber. Shear rates at the lower and side bubble surfaces, estimated from velocity profile of the distributed pigments, agreed well with previously reported estimates (Iwata et al., 2007), which were derived from deformation of a thin shell liquid around the bubble.View full abstractDownload PDF (2451K) -
Ken'ichi Yano, Masahiro MaedaArticle type: Research Papers
Subject area: Transport Phenomena and Fluid Engineering
2008 Volume 34 Issue 4 Pages 424-431
Published: July 20, 2008
Released on J-STAGE: August 01, 2008
JOURNAL RESTRICTED ACCESSIn this study, a fast shake mixing control system was developed that allows control of the quantity of air entrainment, involving low mechanical stress and fluid bubbling by suppressing the sloshing of a fluid's surface. For mixing by horizontal shaking in a circular motion, a CFD simulator was used for analysis of the liquid's behavior, and the quantity of air entrainment during mixing was evaluated. To design a fast mixing control system, the hybrid shape approach was applied. In addition, a 6DOF robot manipulator was used to achieve an arbitrary mixing trajectory and velocity. As a result, air entrainment caused by the sloshing of the liquid's surface was elucidated. The effectiveness of the mixing control technique employing sloshing suppression was shown by simulation and experiment.View full abstractDownload PDF (5987K)
Separation Engineering
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Takashi Kojima, Akira ItoArticle type: Research Papers
Subject area: Separation Engineering
2008 Volume 34 Issue 4 Pages 432-437
Published: July 20, 2008
Released on J-STAGE: August 01, 2008
JOURNAL RESTRICTED ACCESSPermeation and separation performance of a diglycolamine-liquid membrane was studied for CO2/CH4 and CO2/N2 mixed gases. An original support system for a liquid membrane under vacuum-mode permeation was developed using a surface-treated hydrophobic microporous membrane, termed a surface-soaked liquid membrane. A flat membrane module with a 180 mm square membrane surface was made. A diglycolamine/triethylene glycol (50 wt%) liquid membrane of around 8 μm thickness was formed on the surface of the membrane module. Permeation experiments with CO2 mixed gases were conducted under conditions of atmospheric pressure feed-side and vacuum pressure of 4–5 kPa permeate-side. The amine liquid membrane preferentially transported the CO2 component. The separation factor of CO2 was 30 for CO2/CH4 and 40 for CO2/N2. The permeability of CO2 increased at low concentration or low partial pressure. This diglycolamine liquid membrane will be applicable for separation or removal of a low concentration CO2, e.g., CO2 in the air. Besides the permeation experiments, equilibrium absorption of CO2/N2 gas into the amine liquid was measured by a gravitation method. The measured permeabilities used to assess the solution-diffusion model for gas permeation through a liquid membrane. The model is applicable to the permeation of N2, which has a low solubility. For the highly soluble CO2 gas, the model did not match the measured permeability value but may account for the permeability increase at low partial pressure.View full abstractDownload PDF (439K) -
Takumi Shibukawa, Yuichi Ohira, Eiji ObataArticle type: Notes
Subject area: Separation Engineering
2008 Volume 34 Issue 4 Pages 438-443
Published: July 20, 2008
Released on J-STAGE: August 01, 2008
JOURNAL RESTRICTED ACCESSTo optimize the conditions for NO2 gas absorption into an aqueous solution containing a reductant, we investigated the effects of the initial pH and ionic strength of a solution on the absorption rate, absorption efficiency, and selectivity of NO2 into a sodium sulfite solution. A mixed gas containing NO2 was passed through a batch type bubble column absorber, and the concentrations of nitrite and nitrate in the absorbing solution were measured. When the aqueous solution containing a reductant had a pH greater than 5, nitrite was selectively produced, while both nitrate production and nitrite desorption were suppressed. No effects of sodium sulfite concentration and ionic strength on the absorption rate and absorption efficiency were found in this study. The absorption rate and efficiency in the aqueous solution with an oxidized reductant were similar to those in a water system.View full abstractDownload PDF (413K) -
Kinpei Horiuchi, Keigo Matsuda, Koichi Iwakabe, Masaru NakaiwaArticle type: Notes
Subject area: Separation Engineering
2008 Volume 34 Issue 4 Pages 444-447
Published: July 20, 2008
Released on J-STAGE: August 01, 2008
JOURNAL RESTRICTED ACCESSOptimum operation, energy saving, carbon-dioxide emission and cost estimation of a pilot plant of an internally heat-integrated distillation column (HIDiC) separating a twelve-component hydrocarbon mixture to obtain residue-product of crude cyclopentane were studied. From the operation results of the HIDiC at zero external reflux and reboiler free operation, the reduction in CO2 emission by the HIDiC was 56.6 kg/h (453 t/y), which is 63.5% of the total CO2 emission of the conventional distillation column. The HIDiC pilot plant is expected to be reasonable in view of the inflation of the steam cost. The cost estimation results were also compared with those obtained from the conventional column, which showed that the HIDiC pilot plant can provide a strikingly shorter payback time.View full abstractDownload PDF (374K)
Thermal Engineering
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Akio Nakayama, Masayuki TsutsuiArticle type: Notes
Subject area: Thermal Engineering
2008 Volume 34 Issue 4 Pages 448-451
Published: July 20, 2008
Released on J-STAGE: August 01, 2008
JOURNAL RESTRICTED ACCESSIn order to promote the heat transfer of saturated pool nucleate boiling, three types of screws with different diameters were installed concentrically on a horizontally flat heating surface. As a result, the interstice between male and female screws on the flat heating surface was found to supply the bubble nucleus. Heat transfer coefficient of nucleate boiling increased as the diameter of screw became larger. This heating surface was found to promote heat transfer by up to 3.2 times that of the common horizontal heating surface. Within the range of experimental conditions employed, a dimensionless correlation was obtained for the heat transfer of saturated pool nucleate boiling using the horizontally flat heating surface with screws installed concentrically.View full abstractDownload PDF (892K)
Process Systems Engineering and Safety
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Hirohito Katayama, Shigeo KatohArticle type: Research Papers
Subject area: Process Systems Engineering and Safety
2008 Volume 34 Issue 4 Pages 452-457
Published: July 20, 2008
Released on J-STAGE: August 01, 2008
JOURNAL RESTRICTED ACCESSDistribution maps of local age of air and air flow velocity produced by CFD simulation were compared with actual measurements of particle concentrations at eighteen monitoring points as well as three-dimensional air flow vectors 1-m grids in an aseptic pharmaceutical manufacturing room. As a result the air flow patterns assessed by both approaches of simulation with the standard κ–ε model and actual air vector measurements were comparable under conditions of high air change times aseptic room. In this case study particle concentration and local age of air showed no clear relationship due to very low counts of particles. However, CFD simulation displayed its advantages in giving comprehensive air flow pattern and recovery efficiency at local points in an aseptic room.View full abstractDownload PDF (1513K)
Biochemical, Food and Medical Engineering
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Satoshi Kumagai, Mayumi Ota, Hiroyoshi Oka, Nobuyuki Hayashi, Noriyuki ...Article type: Research Papers
Subject area: Biochemical, Food and Medical Engineering
2008 Volume 34 Issue 4 Pages 458-462
Published: July 20, 2008
Released on J-STAGE: August 01, 2008
JOURNAL RESTRICTED ACCESSMonosaccharification of rice hulls by enzymatic hydrolysis combined with hot-compressed water (HCW) treatment was investigated. First, rice hulls were extracted with HCW at 200°C and 3.0 MPa using a percolator type reactor to remove the components other than cellulose. Next, the residual rice hulls were treated with HCW at 280°C and 10 MPa to decompose the cellulose into water-soluble saccharides. The resulting aqueous solution was converted to monosaccharides by enzymatic hydrolysis, and glucose was produced at a yield of 68.1 wt% on cellulose base after a digestion time of 48 h. However, the residual rice hulls were only slightly saccharified and the conversion ratio was only 9.8 wt%.View full abstractDownload PDF (372K)
Materials Engineering and Interfacial Phenomena
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Hironobu Imakoma, Eiji Aizawa, Naoto OhmuraArticle type: Research Papers
Subject area: Materials Engineering and Interfacial Phenomena
2008 Volume 34 Issue 4 Pages 463-470
Published: July 20, 2008
Released on J-STAGE: August 01, 2008
JOURNAL RESTRICTED ACCESSA mathematical model was proposed for a continuous hot-air drying chamber for film coated with single volatile liquid. A single drying chamber and unsteady-state drying operation were considered in the model. Drying rate and temperature of the coated film were estimated by the “drying characteristic model” including an acceleration effect of the mass transfer caused by drying stress, as proposed in our previous study. Simulation of dryer operation was performed for a film coated with polyvinyl alcohol in aqueous solution.
The following results were obtained from the simulation, which may be effective for the design of a continuous hot-air dryer, because such dryers are generally composed of drying chambers connected in series. Temperature of the coated film during the constant rate period increased remarkably with increasing humidity in the drying chamber. Mean moisture content at the chamber exit decreased with increasing residence time, and increased with increasing atmospheric humidity. Since the supply rate of atmospheric air and the adiabatic performance of the dryer wall had a large influence on the energy-saving performance of the dryer, the overall drying energy increased with increasing the residence time. On the other hand, unsteady-state operation and increase of the supply rate of atmospheric air had a small influence on mean moisture content at the chamber exit. As a result, it is suggested that, firstly, the adiabatic performance of the dryer wall and, secondly, atmospheric humidity and the supply rate of atmospheric air should be examined in determining the residence time in relation to the energy-saving performance of the dryer.View full abstractDownload PDF (445K)
Energy
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Toshio Ichihashi, Yoshio NakanoArticle type: Research Papers
Subject area: Energy
2008 Volume 34 Issue 4 Pages 471-476
Published: July 20, 2008
Released on J-STAGE: August 01, 2008
JOURNAL RESTRICTED ACCESSMesoporous silica gels having a narrow pore size distribution of around 2 nm in diameter were synthesized by a solvent evaporation method: C12 with pores of less than 2.0 nm and C18 with pores of 2.2 nm. These synthetic mesoporous silica gels were evaluated from the viewpoints of adsorption capacity for water vapor and the temperature dependency of adsorption and desorption. C12 and C18 showed S-type adsorption isotherms with temperature dependency. C12 exhibited a high effective adsorption capacity for water vapor of 0.11 kg-H2O/kg-silica gel in the range of the relative humidity Φ=0.29 (303 K) andΦ=0.21 (333 K). When a thermo-sensitive polymer (NIPA: N-isopropylacrylamide) was introduced into the C18 mesoporous silica gel, a drastic change was observed in the amount of water vapor adsorbed below and above the phase transition temperature (Tp=306 K) of the thermo-sensitive polymer, resulting from a discontinuous change in the nature of the polymer from hydrophilicity to hydrophobicity. Application of a thermo-sensitive mesoporous silica gel/polymer gel with such properties to a desiccant air conditioning system is expected to reduce regenerating operation temperature considerably.View full abstractDownload PDF (514K) -
Toru Akiyama, Fumihiko Kiso, Hajime MikiArticle type: Research Papers
Subject area: Energy
2008 Volume 34 Issue 4 Pages 477-483
Published: July 20, 2008
Released on J-STAGE: August 01, 2008
JOURNAL RESTRICTED ACCESSSwirling entrained-bed coal gasifier is able to not only produce fuel gas from coal but also melt ash to slag by high temperature. The molten slag is captured on the wall by swirling flow gas, but sometime a part of the slag is entrained by up flow gas. At upper zone of the gasifier, gas temperature is lower than ash melting point. Therefore the entrained molten slag to the upper zone shall solidify and grow. And it disturbs operation. It is necessary to design to lower the height of molten slag entrainment. The slag droplet is transported by the up-flow and the swirling flow. The swirling flow velocity was expressed as a composite of free and forced vortexes. The up-flow velocity was expressed as a function of gasifier exit velocity. These estimates agreed approximately with cold flow model experimental results. Vertical velocity of the slag droplet was calculated from the balance between the up-flow gas velocity and gravity. Tangential velocity was calculated from centrifugal acceleration. The estimated height of slag entrainment agreed approximately with the cold flow model experimental results and EAGLE pilot-plant results.View full abstractDownload PDF (671K)
Environment
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Taichiro Baba, Hiroshi Fukuoka, Naoya ShigemotoArticle type: Research Papers
Subject area: Environment
2008 Volume 34 Issue 4 Pages 484-491
Published: July 20, 2008
Released on J-STAGE: August 01, 2008
JOURNAL RESTRICTED ACCESSSolidities of fluidized-bed fly ash with slag cement were prepared by hydrothermal treatment after adding gypsum, Na3PO4, or Al2(SO4)3. XRD analysis of the solidities was performed and leaching behavior of Pb and F from the solidities was investigated. The fly ash-cement and fly ash-cement-gypsum solidities showed rather high leaching concentration of F and Pb. The F leaching was explained by solubility products of a Ca(OH)2–CaF2 system. The Pb leaching concentrations roughly agreed with the theoretical curve for hydroxo complexes of Pb, showing a strong dependence on pH. Addition of Na3PO4 and Al2(SO4)3 to cement solidities gave katoite and aluminum phosphate, and ettringite, respectively, and these solidities showed lower leaching concentrations of F and Pb than the fly ash-cement and fly ash-cement-gypsum solidities. Capture of F and Pb in crystalline components such as ettringite probably accounts for such leaching suppression.View full abstractDownload PDF (1137K)
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