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Volume 36, Issue 9
Displaying 1-16 of 16 articles from this issue
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Thermodynamics, Physical Properties and Molecular Simulation
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Yi Zhang, Shin-ichi Furukawa, Tomoshige NittaArticle type: Research Paper
2003 Volume 36 Issue 9 Pages 1085-1094
Published: 2003
Released on J-STAGE: June 08, 2004
JOURNAL RESTRICTED ACCESSA μVT-ensemble Orientational-Bias Monte Carlo technique has been utilized to simulate adsorption isotherms of pure and mixed propane/propylene in NaA zeolite at 298.15 K. An atomic potential model of Catlow et al. (1991) and Oie et al. (1981) is found to represent the experimental isotherms satisfactorily. The simulations reveal the reason why propylene is adsorbed much more strongly than propane; i.e. the adsorption energy of propylene is 10 kJ/mol larger than that of propane, mainly through the Coulomb interactions between propylene molecules and zeolite atoms/Na ions. Pure adsorption isotherms of propane/propylene obtained from the simulations are correlated with four theoretical models: Langmuir, multi-site occupancy, two-dimensional van der Waals fluid and Ruthven+U models. The latter three models are found to fit much better than the Langmuir model because they take account of interactions between adsorbed molecules, the contribution of which has been clarified to be significant from the simulations.
The simulation isotherms of propane/propylene mixtures, calculated at 100 kPa in total pressure and 298.15 K, show a novel feature of mixed-gas adsorption; i.e. the adsorption of propane, a weak adsorbate, increases with the decrease in the partial pressure of propane and reaches a maximum in a low mole fraction of proylene. This unusual mixed-gas adsorption has been ascribed to a “sorption effect” through the molecular interactions of propylene molecules appreciably adsorbed in zeolite. The simulation mixed-gas isotherms are qualitatively well predicted by the above three models, while the Langmuir model with the IAST (Ideal Adsorbed Solution Theory) fails to predict the existence of a maximum adsorption of propane.View full abstractDownload PDF (2241K)
Transport Phenomena, Fluid Mechanics and Mixing
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Shiro YoshikawaArticle type: Research Paper
2003 Volume 36 Issue 9 Pages 1076-1084
Published: 2003
Released on J-STAGE: June 08, 2004
JOURNAL RESTRICTED ACCESSThe relation between mass transfer and flow characteristics in the shell side of a hollow-fiber dialyzer has not been investigated sufficiently because of the tangled flow path. In this paper, the effects of velocity distribution of dialysate on mass transfer in the shell side were investigated experimentally. In order to measure the velocity at various radial and axial positions of a dialyzer, cut dialyzers of various lengths were used. The velocity distributions over the section of the cut dialyzers were measured by means of the electro-chemical method. In addition, the concentration distribution at the cross section of the outlet of lumens of the hollow-fibers was measured when the deionized water and aqueous solution of potassium chloride were fed into a dialyzer countercurrently. Potassium chloride was taken up as a model of low molecular weight species in blood. The velocity was not constant over cross sections of the shell side and the concentration was distributed over the cross section of the outlet of the lumens of the hollow-fibers. These results showed that the mass transfer coefficient in the shell side was varied over the dialyzer. It was considered that the mass transfer coefficient at the local radial position should be discussed in order to make the transport process in the shell side clear. The correlation between the Sherwood number and the Reynolds number based on the velocity and the mass transfer coefficient at local radial positions of the shell side was made. The result of the correlation suggested that the transport process in the center region of the shell side was similar to that in a laminar circular pipe flow.View full abstractDownload PDF (670K) -
Fadilah Hasim, Masamichi Yoshida, Hisashi MiyashitaArticle type: Short Communication
2003 Volume 36 Issue 9 Pages 1116-1122
Published: 2003
Released on J-STAGE: June 08, 2004
JOURNAL RESTRICTED ACCESSAn experimental investigation on compound heat transfer enhancement by a combination of a helically ribbed tube with twisted tape inserts was performed. The measurement of heat transfer coefficient as well as the pressure drop was performed in order to evaluate the performance of enhanced tubes using the equal pumping power evaluation method. The heat transfer coefficient was obtained by means of Wilson’s method for the Reynolds number ranging from 300 to 30,000. The combination of smoothed tube and twisted tape having a clearance NDC = 0.07 accomplished the highest performance in the laminar region. On the other hand, the combination of helically ribbed tube and twisted tape having a clearance NDC = 0.02 gave the highest performance in the turbulent region. The reasons for these results are discussed well in terms of the compound effect and clearance effect.View full abstractDownload PDF (1253K)
Materials and Devices
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Shigeru Sugiyama, Satoshi Kawakami, Shinya Tanimoto, Minako Fujii, Hir ...Article type: Research Paper
2003 Volume 36 Issue 9 Pages 1095-1100
Published: 2003
Released on J-STAGE: June 08, 2004
JOURNAL RESTRICTED ACCESSFormation of boehmite sol from aluminum isopropoxide in aqueous solution was examined with XRD and solid state NMR to reveal that the hydrolysis of the isopropoxide was completed within a rather short reaction time of 1 h while a longer reaction time of 24 h had been employed in the typical preparation procedure. Although it had been mentioned that γ-alumina was formed from the calcination of boehmite at 1073 K, it was suggested that η-alumina, not γ-type, was obtained after the calcination, based on XRD analyses. In order to develop the employment of boehmite sol as the precursor material, the layer of active alumina and its precursor was formed with the dip-coating technique on glass, stainless steel, magnesia and α-alumina plates to show that approximately 1 μm layers were uniformly formed on glass and stainless steel plates while thickness of the layer formed on magnesia and α-alumina was not estimated due to the reflection of uneven plates of those oxides.View full abstractDownload PDF (507K)
Separations
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Toshinori Tsuru, Terutaka Toyosada, Tomohisa Yoshioka, Masashi Asaeda2003 Volume 36 Issue 9 Pages 1063-1069
Published: 2003
Released on J-STAGE: June 08, 2004
JOURNAL RESTRICTED ACCESSA photocatalytic membrane reactor, in which permeation of solutes through a membrane and a photocatalytic reaction occur simultaneously, that is, a photocatalytic membrane reactor, is described. Using trichloroethylene (TCE), a decomposition ratio in excess of 95% in the permeate stream to that in the feed stream was achieved by means of porous titanium oxide (TiO2) membranes, when approximately 1 ppm TCE solution was fed to the TiO2 membranes under irradiation by a blacklight. The decomposition ratio, defined as the concentration ratio of the permeate to the feed stream, decreased with applied pressure and the feed concentration. A proposed photocatalytic reaction model where a photocatalytic reaction in the outer reaction zone and in the inner reaction zone under membrane permeation conditions is consistent with the observed experimental data.View full abstractDownload PDF (1250K) -
Nobuhiro Yamanouchi, Akira Ito, Kazuaki YamagiwaArticle type: Research Paper
2003 Volume 36 Issue 9 Pages 1070-1075
Published: 2003
Released on J-STAGE: June 08, 2004
JOURNAL RESTRICTED ACCESSVapor permeation of a benzene and cyclohexane mixture was studied using a liquid membrane of triethylene glycol (TEG), which is supported on the surface of a microporous hydrophobic membrane. Permeation experiments were conducted using a flat-type membrane cell under the conditions of atmospheric pressure on the feed side and a vacuum on the permeate side. Mixed vapors of benzene/cyclohexane and water were fed into the membrane cell by a carrier gas. The benzene vapor preferentially permeated through the TEG liquid membrane, that is, the TEG liquid membrane had a selectivity for the aromatic hydrocarbon. The separation factor for benzene over cyclohexane was around 8. This selectivity corresponded to the vapor-liquid equilibrium of hydrocarbons dissolved in TEG. Adding a salt to the TEG liquid membrane caused an increasing aromatic selectivity as well as a decreasing vapor permeation rate. This effect was examined using various salts, which were formulated using alkali metal and halogen ions. A liquid membrane of a TEG and KCl mixture showed a separation factor of over 400. KCl was the most effective agent to enhance the benzene selectivity. The ion components in the TEG liquid membrane may cause a kind of facilitated transport effect on the aromatic hydrocarbon vapor.View full abstractDownload PDF (635K) -
Hidenori Tsubomizu, Rie Horikoshi, Kazuaki Yamagiwa, Katsumi Takahashi ...Article type: Short Communication
2003 Volume 36 Issue 9 Pages 1107-1110
Published: 2003
Released on J-STAGE: June 08, 2004
JOURNAL RESTRICTED ACCESSFoam fractionation of poly(vinyl alcohol) with external foamate reflux was carried out with a perforated plate foam column. The insertion of perforated plates significantly decreased the liquid distributed in the foam. Consequently, the enrichment factor in the perforated plate column was twice as much as that in the normal foam column. The maximum enrichment factor of about 25 and separation factor of about 160 were obtained at an aeration rate of 300 cm3/min and initial PVA concentration of 1000 g/m3. The insertion of perforated plates was concluded to be effective for enrichment of surface active material through foam fractionation with external foamate reflux.View full abstractDownload PDF (402K) -
Shigetoshi Kobuchi, Takeshi Furuya, Kenji Fukuchi, Yasuhiko AraiArticle type: Short Communication
2003 Volume 36 Issue 9 Pages 1123-1126
Published: 2003
Released on J-STAGE: June 08, 2004
JOURNAL RESTRICTED ACCESSAn extended Radke–Prausnitz equation is useful in predicting the adsorption equilibria of organic multi-solute aqueous solutions on activated carbon. It has an advantage that, if the single-solute and two-solute parameters are available, the calculation of adsorption equilibria for more than three-solute systems can be carried out without additional parameters. The authors have previously proposed an empirical method for estimating the single-solute parameters using the physical properties of solutes and have obtained good prediction results for thirteen single-solute systems. In this study, the two-solute parameters of the extended Radke–Prausnitz equation are correlated with the normal boiling point and molecular weight of solutes and the prediction performances are examined for adsorption equilibria of six two-solute aqueous solution systems. The prediction results are in good agreement with the experimental data.View full abstractDownload PDF (338K)
Particle Technology and Fluidization
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Donghyun Lee, Norman Epstein, John R. GraceArticle type: Short Communication
2003 Volume 36 Issue 9 Pages 1111-1115
Published: 2003
Released on J-STAGE: June 08, 2004
JOURNAL RESTRICTED ACCESSBy taking account of the experimentally determined variation of voidage with the gas velocity at minimum gas-liquid fluidization of a bed of solid particles, it is shown, using the same experimental database as in the earlier paper by Lee et al. (2001a), that the model which best predicts the minimum liquid fluidization velocity is a variant of the gas-perturbed liquid model of Zhang et al. (1995), but with the buoyancy term based on the gas-liquid mixture rather than the liquid alone. The best value of the constant in the viscous term of the Carman–Ergun drag equation involved is 165, intermediate between Carman’s 180 and Ergun’s 150.View full abstractDownload PDF (364K)
Process Systems Engineering
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Cheng-Chih Li, Hsiao-Ping HuangArticle type: Research Paper
2003 Volume 36 Issue 9 Pages 1023-1033
Published: 2003
Released on J-STAGE: June 08, 2004
JOURNAL RESTRICTED ACCESSPLSR (partial least squares regression) has become a basic tool for chemometrics, monitoring and modeling of processes, etc. The basic idea of PLSR is to relate two data matrices X and Y into a multivariate linear model, for analysis of the data with noisy and collinear variables. In industrial processes, sub-models of the specific units are built for monitoring and engineering process control. However, we know that these process units are not individually independent. As a result, the full model is usually desirable. In an actual process, there are thousands to ten thousands of variables being measured and conveniently recorded instantaneously. It is not practical to deal with such a large number of variables to construct a full model at time, especially they are collinear and embedded with noise. In this paper, the linear regression model merging procedure is proposed to incorporate PLSR models of subsystems into a full model. By way of this approach, the computation time and memory can thus significantly be reduced. It is quite suitable to merge the process sub-models built from PLSR into the complete one. The method could be extended to dynamic and non-linear modeling easily. Two examples for dynamic modeling and monitoring are presented for illustration. One is the dynamic modeling of a 4 × 4 linear process. Second one is the process monitoring of a double effect evaporator.View full abstractDownload PDF (653K) -
Chia Huang Yen, David Shan Hill Wong, Shi Shang JangArticle type: Research Paper
2003 Volume 36 Issue 9 Pages 1034-1044
Published: 2003
Released on J-STAGE: June 08, 2004
JOURNAL RESTRICTED ACCESSCombinatorial techniques have become more and more important in many areas of chemistry and chemical engineering research. It was suggested that simulated annealing can be used to improve the efficiency of sampling in combinatorial methods. However, without priori model estimates of fitness function, true importance sampling cannot be performed. In this case, the efficiency of annealing is only as good as random search. We suggested that a simple prediction model using currently available data can be constructed using a generalized regression neural network. An index of our uncertainty about a point in the search space can also be established using information entropy. An information free energy combined the two indices to direct the search so that importance sampling is performed. Two benchmark problems were used to model the optimization problem involved in combinatorial synthesis and library design. We showed that when importance sampling is performed, the combinatorial technique became much more effective. The improvement in efficiency over undirected methods is especially significant when the size of the problem becomes very large.View full abstractDownload PDF (3184K)
Biochemical, Food and Medical Engineering
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Takaaki Tanaka, Mihoko Yamamoto, Masafumi Takahashi, Tomoyuki Fujii, M ...Article type: Research Paper
2003 Volume 36 Issue 9 Pages 1101-1106
Published: 2003
Released on J-STAGE: June 08, 2004
JOURNAL RESTRICTED ACCESSThe kinetics of enzymatic oxidative polymerization of 4-chloroguaiacol by laccase was studied. 4-Chloroguaiacol, a model compound of the chloroguaiacols formed in the bleaching process in the pulp industry, was oxidized by laccase from Trametes sp. Ha1 to eliminate chloroguaiacols from pulp wastewater by polymerization and precipitation. On the basis of the reaction rate obtained from the decrease in the 4-chloroguaiacol concentration, the optimum pH of the reaction was 4–5 and the apparent Michaelis constant Km for the reaction was more than 5 mmol dm–3. However, the value of Km obtained from the dependence of oxygen consumption rate on the concentration of 4-chloroguaiacol was 0.092 mmol dm–3. The reaction rate was expressed as the sum of the enzymatic oxidation rate of 4-chloroguaiacol and the polymerization rate of the radical formed in the enzymatic oxidation. The kinetics of the enzymatic oxidative polymerization shown in this study will be useful to understand those of the enzymatic oxidation of other phenolic compounds.View full abstractDownload PDF (370K) -
Hideaki Nagami, Keiichi Yamamoto, Hideaki Ichihara, Yoko Matsumoto, Ry ...Article type: Short Communication
2003 Volume 36 Issue 9 Pages 1127-1129
Published: 2003
Released on J-STAGE: June 08, 2004
JOURNAL RESTRICTED ACCESSThe inhibitory effects of hybrid liposomes on the growth of human breast tumor (MDA-MB-453) cells in vitro were examined. The 50% inhibitory concentration of hybrid liposomes composed of 95 mol% dimyristoylphosphatidylcholine (DMPC) and 5 mol% polyoxyethylenedodecyl ether (C12(EO)23) was remarkably reduced compared with that of DMPC liposome and C12(EO)23 micelle. It was noteworthy that the induction of apoptosis by hybrid liposomes without antitumor drugs was obtained for human breast tumor cells.View full abstractDownload PDF (760K)
Safety, Environment and Energy
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Atsushi Tatani, Tetsuya Imai, Yukihisa FujimaArticle type: Research Paper
2003 Volume 36 Issue 9 Pages 1057-1062
Published: 2003
Released on J-STAGE: June 08, 2004
JOURNAL RESTRICTED ACCESSA small amount of manganese compound contained in limestone as an impurity takes an important role of a catalyst for the sulfite oxidation reaction. In the present work, it was found that Mn2+ coprecipitates with the calcium sulfite solid in a continuously-stirred tank reactor under the similar conditions as that in the absorber tank of the wet limestone scrubbing process. The experimental results indicated that the coprecipitaton ratio of Mn2+ to calcium sulfite solid increases linearly proportional to the dissolved Mn2+ concentration in the solution upto a critical Mn2+ concentration and remains constant in the range of higher Mn2+. It was also found that Mn2+ did not coprecipitate with gypsum crystal at all.View full abstractDownload PDF (451K)
General Research and Others
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Lei Rong , Keiji Yasuda , Masaaki Nakamura, Nobuhisa Kato, Kouji Kawak ...Article type: Research Paper
2003 Volume 36 Issue 9 Pages 1045-1049
Published: 2003
Released on J-STAGE: June 08, 2004
JOURNAL RESTRICTED ACCESSThe decomposition performance of p-chlorophenol in aqueous solution by combination of ultrasound and ultraviolet light was examined. The decomposition of p-chlorophenol in aqueous solution was a pseudo-first-order reaction. The decomposition rate constant increased with increasing ultrasonic intensity and became lower as the initial concentration increased. The p-chlorophenol in aqueous solution was decomposed by OH radicals and photolysis. The synergy effect between ultrasound and ultraviolet light was observed. It was considered that the amount of OH radicals increased due to the photolysis of H2O2, which formed from the sonolysis of water. The decomposition of p-chlorophenol was simply modeled and kinetic analysis was performed. The calculated results were agreed with the experimental data.View full abstractDownload PDF (406K) -
Aki Mitomo, Toyoyuki Sato, Nobusuke Kobayashi, Shigenobu Hatano, Yoshi ...Article type: Research Paper
2003 Volume 36 Issue 9 Pages 1050-1056
Published: 2003
Released on J-STAGE: June 08, 2004
JOURNAL RESTRICTED ACCESSActivated coke is produced from ligneous biomass molded pellets by different carbonization methods and conditions as the absorbents of hydrogen sulfide with the object of both the biomass recycle and the gas purification in a biomass gasification process. We clarified the differences of activated coke characteristics influenced by different production processes, such as the carbonization temperature, carbonization time and carbonization gases. The carbonization temperature was maintained from 723 to 1123 K, the carbonization time was set from 30 to 250 min and the carbonization gas used was either nitrogen or steam. The production process does not include the activation process for reducing the production steps and costs. The activated coke quality and characteristics that were evaluated were the specific surface area, pore size distribution, particle density and adsorption capacity of hydrogen sulfide. Other commercial adsorbents, such as activated carbon and activated char, were used to compare the adsorption performance. The measured adsorption performance of activated coke using the steam carbonization was better than that using the nitrogen carbonization. Comparing the activated coke with commercial absorbents, produced activated coke showed good adsorption results. There is a possibility of using activated coke in the gas purification process in a biomass recycling system instead of using expensive commercial adsorbents or other gas purification processes.View full abstractDownload PDF (552K)
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