JOURNAL OF CHEMICAL ENGINEERING OF JAPAN
Online ISSN : 1881-1299
Print ISSN : 0021-9592
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Volume 28, Issue 2
Displaying 1-23 of 23 articles from this issue
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Original Papers
  • Rheological Predictions of Dispersion of Powder in Ceramic Injection Molding Mixtures
    Kenji Okada, Shin Akasaka, Hiroyuki Kurisaka, Yasuharu Akagi
    1995 Volume 28 Issue 2 Pages 137-143
    Published: 1995
    Released on J-STAGE: March 26, 2005
    DOIhttps://doi.org/10.1252/jcej.28.137
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    The process variables of mixing to improve the dispersion of powder in ceramic injection molding mixtures were examined for mixtures consisting of polyethylene and different kinds of ceramic powders. The dispersion in the mixtures mixed under various conditions was evaluated using the dynamic rheological measurements of the mixtures. The degree of dispersion in the mixtures was highly influenced by the mixing temperature and mixing speed of the mixer. With increasing mixing temperature the viscosity of the mixtures increased, and the degree of dispersion in the mixtures reduced as the particle size became smaller. On the other hands, dispersion in the mixtures was improved with decreasing mixing temperature. This improvement in the dispersion resulted from the increase in the mixing strength of the mixer to break down agglomerates with increasing viscosity of the matrix. Increasing the mixing speed was also a processing parameters that improved the dispersion of powder in the mixtures. Furthermore, a simple rheological model was proposed to evaluate the mixing strength of the mixer to disperse the particles as a function of particle size and particle concentration.
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  • Correlation of Solubilities for CO2 and NH3 in H2O Using Soave-Redlich-Kwong Equation of State with MHV2 Mixing Rule
    Kenji Mishima, Junji Sugino, Masakuni Ueno, Kiyoshi Matsuyama, Masanor ...
    1995 Volume 28 Issue 2 Pages 144-147
    Published: 1995
    Released on J-STAGE: March 26, 2005
    DOIhttps://doi.org/10.1252/jcej.28.144
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    The flexibility and applicability of the modified Huron-Vidal second order (MHV2) mixing rule have been examined for the correlation of solubilities for CO2 and NH3 in H2O as an example of a system containing volatile weak electrolytes. The MHV2 mixing rule is one of the excess Gibbs energy (gE) mixing rules. The gE mixing rules are well known to be able to predict vapor-liquid equilibria (VLE) of polar or non-polar mixture systems under high pressure. We have used the Soave-Redlich-Kwong equation of state (SRK-EOS) with the MHV2 mixing rule. Assuming a series reaction between CO2 and NH3 in the aqueous phase and the temperature dependence of the equilibrium constant, the solubility behavior of the CO2-NH3-H2O system can be correlated with reasonable accuracy.
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  • Regeneration of CO2-Loaded Carbonate Solution by Reducing Pressure
    Susumu Nii, Yoshiro Iwata, Katsuroku Takahashi, Hiroshi Takeuchi
    1995 Volume 28 Issue 2 Pages 148-153
    Published: 1995
    Released on J-STAGE: March 26, 2005
    DOIhttps://doi.org/10.1252/jcej.28.148
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    For the purpose of developing a CO2 separation process for flue gas of low CO2 partial pressure, a vacuum regeneration method for an absorbent with low CO2-loading was experimentally investigated. Since additional energy is consumed for water vaporization accompanied by CO2 desorption in the regeneration step, reducing the generation of water vapor becomes important for energy saving. A solution of potassium or sodium carbonate and bicarbonate mixture was used as a model solution of CO2-loaded absorbent; a carbonate solution containing diethanolamine (DEA) was also examined. Rates of CO2 desorption and water vaporization were obtained under the operating conditions of various pressures and temperatures. The rate ratio of water vaporization to CO2 desorption became minimum at a pressure equal to the vapor pressure of water. The rate of CO2 desorption at this pressure increased with temperature until 343 K and the increase was minimal beyond this temperature. The desorption rate was enhanced by the addition of DEA to the carbonate solution, and the rate reached a maximum at a high DEA concentration.
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  • Multi Stage Electrodialysis for Separation of Two Metal Ion Species
    Katsuroku Takahashi, Homare Sakurai, Susumu Nii, Kenichi Sugiura
    1995 Volume 28 Issue 2 Pages 154-158
    Published: 1995
    Released on J-STAGE: March 26, 2005
    DOIhttps://doi.org/10.1252/jcej.28.154
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    A multistage electrodialysis with reflux flow is proposed for the separation of two metal ions. Separation of potassium ion and sodium ion has been investigated by use of batch dialysis with and without electric field and continuous electrodialysis with a four-stage dialyzer. The difference in the permselectivity between the dialysis with and without electric field was not appreciable for the system of potassium and sodium ions with the cation exchange membrane used. For continuous electrodialysis, the concentration ratio between potassium and sodium ions in the top product (the outlet solution from the recovery side) increased with the reflux flow rate and the number of stages. When the reflux flow rate was zero, the concentration ratio with the four-stage dialyzer was 1.5 which was almost the same as with the two-stage dialyzer consisting of a single membrane, while the ratio reached 3.6 for a reflux ratio of 0.7.
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  • Characteristics of Helium Adsorption on Microporous Solids under Cryogenic Conditions
    Mikio Kumita, Junya Ozaki, Jun Kobayashi, Mutsuhiro Ito, Fujio Watanab ...
    1995 Volume 28 Issue 2 Pages 159-164
    Published: 1995
    Released on J-STAGE: March 26, 2005
    DOIhttps://doi.org/10.1252/jcej.28.159
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    A new volumetric method using helium adsorption was proposed to make microporous solids with clear pore structures. Adsorption equilibria of helium on silica-alumina, activated carbon and zeolites were measured at a temperature around its boiling point. The helium adsorption isotherms obtained were compared with the nitrogen adsorption isotherms. As a result, the amounts of helium adsorbed on all adsorbents used were much greater than those of nitrogen adsorbed in the low relative pressure region, indicating that helium is a useful molecule to investigate microporous structures of such materials. Therefore, the possibility that this method be applied to micropore characterization was suggested. The results of B.E.T. specific surface areas also support this conclusion.
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  • Recovery of Heavy Metal Ion from Slurry Adsorbent by Packed Column of Ion Exchange Membrane
    Hisao Takase, Naotake Katoh
    1995 Volume 28 Issue 2 Pages 165-170
    Published: 1995
    Released on J-STAGE: March 26, 2005
    DOIhttps://doi.org/10.1252/jcej.28.165
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    The recovery of heavy metal ions adsorbed on slurry was examined by using a column packed spirally with an ion exchange membrane. The slurry solution containing partly eluted heavy metal ions was continuously fed into the column. Theoretical treatments for rate of mass transfer and equilibrium were carried out by a numerical calculation. The calculated results showed good agreement with the experimental results. It was assumed that the value of liquid-film mass transfer coefficient for the ion exchange membrane in the slurry solution is 0.37 time as large as that in the slurry free aqueous solution. Two equilibrium relationships for the heavy metal ion enabled us to estimate the optimal concentration of eluting agent. With respect to the equilibrium relationships, the first is between aqueous solution and slurry adsorbent and the second is between aqueous solution and spirally packed ion exchange membrane. The desorption of ions from the membrane was discussed experimentally and theoretically.
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  • Computer Simulation of Agitation Fluidized Bed Granulation by a Two-Dimensional Random Addition Model
    Satoru Watano, Takashi Morikawa, Kei Miyanami
    1995 Volume 28 Issue 2 Pages 171-178
    Published: 1995
    Released on J-STAGE: March 26, 2005
    DOIhttps://doi.org/10.1252/jcej.28.171
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    Computer simulation by a two-dimensional random addition model was proposed to elucidate the mechanisms of granule growth and compaction process of agitation fluidized bed granulation. In this paper, adhesion force by liquid bridge and separation force by agitator rotation were taken into consideration for adhesion probability of colliding granules. Effects of moisture content and agitator rotational speed on granule diameter, shape and internal structure were investigated theoretically. This simulation was applied to actual granulation, in which lactose and corn starch mixed in a weight ratio of 7:3 were granulated by an aqueous solution of hydroxypropylcellulose. Close agreement between simulated and experimental results was obtained.
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  • Saturation Carrying Capacity of Gas and Flow Regimes in CFB
    Dinglong Bai, Kunio Kato
    1995 Volume 28 Issue 2 Pages 179-185
    Published: 1995
    Released on J-STAGE: March 26, 2005
    DOIhttps://doi.org/10.1252/jcej.28.179
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    This paper presents a generalized approach to the saturation carrying capacity of gas, Gs*, in high-velocity fluidized beds. Starting from discussion of the variation of solid holdup in the dense region of circulating fluidized beds (CFBs) with the solid circulation rate, we defined the saturation carrying capacity of gas, Gs*, as the solid circulation rate at which a maximum achievable or saturation solids concentration at the dense region of the CFB starts to be reached. It has been experimentally demonstrated that above Gs*, solid concentrations in the dense region are really independent of changes in the solid circulation rate, the riser diameter, solids feeding system and the solids inventory, and a characteristic S-shaped axial solid holdup distribution would be observed. Based on this physical phenomenon, the saturation carrying capacity of gas was determined as functions of gas velocity and gas-solid properties, and a generalized correlation was therefore proposed on the basis of collected literature data. Finally, a flow diagram in which the flow conditions for occurring of S-shaped and exponential profiles of solids holdup was presented.
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  • Evaluation of Pore Structure and Electrical Properties of Nanofiltration Membranes
    Xiao-Lin Wang, Toshinori Tsuru, Masanori Togoh, Shin-ichi Nakao, Shoji ...
    1995 Volume 28 Issue 2 Pages 186-192
    Published: 1995
    Released on J-STAGE: March 26, 2005
    DOIhttps://doi.org/10.1252/jcej.28.186
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    Structural parameters and electrical properties of nanofiltration membranes (Desal-5, NF-40, NTR7450 and G-20) were determined with permeation experiments of aqueous solutions of neutral solutes (alcohols and saccharides having different molecular weights) and sodium chloride. The pore radii of these nanofiltration membranes were estimated to range from 0.4 to 0.8 nm based on the steric-hindrance pore model. Neither the constant surface charge density nor the constant surface electrical potential were suitable for interpreting NaCl concentration dependency of reflection coefficients. The fixed charge density of these membranes was evaluated on the basis of the Teorell-Meyer-Sievers model; a simple empirical equation was proposed to represent the dependency of the fixed charge density on NaCl concentration.
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  • Calculation of Concentration Dependent Mutual Diffusion Coefficients for the Penetration Period of Sorption Process in Polymer Film
    Shigetoshi Kobuchi, Yuji Sano, Shuichi Yamamoto
    1995 Volume 28 Issue 2 Pages 193-197
    Published: 1995
    Released on J-STAGE: March 26, 2005
    DOIhttps://doi.org/10.1252/jcej.28.193
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    A new method of calculating concentration dependent mutual diffusion coefficients was proposed for the penetration period of adsorption and desorption processes in polymer film. The diffusion equation for a slab based on a dissolved solid coordinate with constant surface concentration was solved numerically for the sorption process, assuming a power function for the concentration dependence of the diffusion coefficient. The solvent concentrations corresponding to the apparent diffusion coefficients, which were calculated easily from the experimental sorption rate curves of the penetration period, were correlated with the surface concentrations using the power value of the concentration dependence as the parameter. Using this correlation, the relation between the diffusion coefficient and the concentration was obtained easily by trial calculation.
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  • Characteristics of Immobilized Lactobacillus delbrueckii in a Liquid-Solid Fluidized Bed Bioreactor for Lactic Acid Production
    Henian Wang, Minoru Seki, Shintaro Furusaki
    1995 Volume 28 Issue 2 Pages 198-203
    Published: 1995
    Released on J-STAGE: March 26, 2005
    DOIhttps://doi.org/10.1252/jcej.28.198
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    Continuous lactic acid production using immobilized L. delbrueckii was investigated. To evaluate the performance of the liquid-solid fluidized bed reactor using immobilized cells, the release rate of free cells from support surfaces and contribution of the free cells, which co-exist with immobilized cells in the broth, to lactic acid production were studied quantitatively. The results showed that the free cells played an important role at low dilution rate. If the dilution rate was increased, the effect of free cells on lactic acid production decreased quickly. Increasing the holdup of immobilized particles in the reactor lowered the contribution of free cells to the lactic acid production. Finally, the performance of the reactor was studied under the conditions of low growth nutrients. The results suggested that there was more active cell growth within the gel beads in the fluidized bed reactor than in the cell recycle reactor using membrane.
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  • Oxidative Dehydrogenation of Ethane in the Presence and Absence of Tetrachloromethane over Magnesium Sulphate
    Shigeru Sugiyama, Kohji Satomi, Hiromu Hayashi, Michie Tanaka, John B. ...
    1995 Volume 28 Issue 2 Pages 204-209
    Published: 1995
    Released on J-STAGE: March 26, 2005
    DOIhttps://doi.org/10.1252/jcej.28.204
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    The oxidative dehydrogenation of ethane in the presence and absence of tetrachloromethane (TCM) has been investigated over MgSO4 at reaction temperatures between 723 and 998 K. Although the conversion of ethane over MgSO4 was increased on addition of TCM to the feedstream, the ethylene selectivity was not influenced except at 723 K. The results of XRD and XPS measurements suggest that MgCl2 is formed on the surface of the the catalyst from the vapor phase TCM and may be responsible for the effects observed in the presence of TCM. At reaction temperatures greater than 898 K, higher conversion of ethane can be attributed to the formation of MgO from the decomposition of MgSO4.
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