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Showing papers in "Journal of Chemical Engineering of Japan in 1992"


Journal ArticleDOI
TL;DR: The Scaba SRGT agitator with six blades when gassed draws between 1 and 0.8 times the ungassed power in fluids of low and moderate viscosity respectively as discussed by the authors.
Abstract: The Scaba SRGT agitator with six blades when gassed draws between 1 and 0.8 times the ungassed power in fluids of low and moderate viscosity respectively. Under similar conditions, the gassed Rushton turbine draws 0.5 to 0.4 times the ungassed power. In addition, some three times more gas can be handled at the same ungassed power by this SRGT before flooding occurs. The increased hold-up achieved by the 6SRGT is commensurate with the increased power input and it is argued that the potentially extra power available should be able to give a similarly enhanced kLa. The 6SRGT agitator also gives an equivalent homogenisation performance to a standard Rushton turbine agitator of the same size at the same gassed power input. When gassed reactors are fitted with motors of sufficient power to be capable of running at full speed when ungassed, this agitator offers simple retrofitting possibilities potentially leading to considerably enhanced performance.

76 citations


Journal ArticleDOI
TL;DR: In this paper, an enantioselective membrane was prepared by introducing an amino acid condensate with glutaraldehyde into a polysulfone membrane matrix, and the optical resolution of phenylalanine from aqueous racemate solutions was examined under the concentration and pressure gradient across the membrane respectively.
Abstract: An enantioselective membrane was prepared by introducing an amino acid condensate with glutaraldehyde into a polysulfone membrane matrix. The optical resolution of phenylalanine from aqueous racemate solutions was examined under the concentration and pressure gradients across the membrane respectively. The membrane was permeable with respect to D-phenylalanine in preference to L-phenylalanine, and the separation factor was 1.25 to 4.10.The solute fluxes were analyzed on the basis of a permeation model consisting of both diffusing flow and viscous flow.Using the solute fluxes of D- and L-amino acids, the separation factor could be successfully expressed by the solute permeability of amino acid and the volume flux.

64 citations


Journal ArticleDOI
TL;DR: The solubilities of high-boiling components (solid state) in supercritical carbon dioxide have been correlated by using a solution model based on the regular solution model coupled with the Flory-Huggins equation.
Abstract: The solubilities of high-boiling components (solid state) in supercritical carbon dioxide have been correlated by using a solution model based on the regular solution model coupled with the Flory-Huggins equation

58 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the effect of the extraction of furfural by supercritical CO 2 on the selectivity and yield of the furfur from xylose.
Abstract: Furfural formation from xylose is a typical successive reaction in which the furfural produced in a reactor disappears by side reactions such as polymerization and decomposition. In this work we investigated the effect of the extraction of furfural by supercritical CO 2 on the selectivity and yield of the furfural. Furthermore, based on kinetic data we proposed a reaction model for furfural formation with or without supercritical CO 2 extraction

45 citations


Journal ArticleDOI
TL;DR: In this paper, a hybrid operation of membrane permeation and gas absorption was proposed for removing carbon dioxide from flue gases, and the performance of a multiple hollow-fiber (HF) module was comparable to that of a packed column.
Abstract: For the purpose of removing carbon dioxide from flue gases a novel operation, “permabsorption”, a hybrid operation of membrane permeation and gas absorption was proposed. Permeability of a non-porous hollow-fiber (HF) membrane made of polydimethylsiloxane for PUre CO2 and O2 was obtained in this simple-operation mode, the observed values being in reasonable agreement with literature values. High permselectivity can be attained by using an appropriate absorbent liquid. In the permabsorption of CO2 using alkaline solution, the permeation rate could be expressed by a model based on membrane permeation with gas absorption. The performance of a multiple-HFs module was comparable to that of a packed column. This result implies that the permabsorption method provides the possibility of operation at lower liquid flow rate than in packed columns and, therefore, of energy-saving CO2 removal from flue gases.

44 citations


Journal ArticleDOI
TL;DR: In this article, an electrical conductivity method was tested using an ammonium aluminum sulfate-water model system and the system was used as a model system for electrical conductivities.
Abstract: An electrical conductivity method was tested. The system of ammonium aluminum sulfate-water was used as a model system

40 citations


Journal ArticleDOI
TL;DR: In the culture of red beet hairy root, the red pigment was released from the cells into medium when the cells were subjected to the culture condition under O2 starvation by keeping the concentration of dissolved oxygen in medium at 0 ppm.
Abstract: In the culture of red beet hairy root, the red pigment (mainly betanin) was released from the cells into medium when the cells were subjected to the culture condition under O2 starvation by keeping the concentration of dissolved oxygen in medium at 0 ppm. The amount of released pigment increased with increasing time length of O2 starvation during 26 h. However, an O2 starvation time of less than 16 h was employed to shorten the lag time for cell growth resumption after this starvation treatment. An adsorption column with a hydrophobic resin, Sepabeads SP 207 (styrene-divinylbenzene copolymer), was incorporated in a bioreactor system and the long-term culture of hairy root was carried out with repeated operations of cell growth, pigment release and recovery. In the culture with an O2 starvation time of 16 h, an extracellular production rate of pigment of 11.3 × 10–5 kg/(m3-broth·h) was obtained on the average.

38 citations


Journal ArticleDOI
TL;DR: A copolymer of glycidyl methacrylate (GMA) and N-isopropyl acrylamide (NIPAM) forms a reversibly soluble-insoluble (S-IS) polymer, whose solubility changes with the temperature of the solution as mentioned in this paper.
Abstract: A copolymer of glycidyl methacrylate (GMA) and N-isopropyl acrylamide (NIPAM) forms a reversibly soluble-insoluble (S-IS) polymer (GMA-NIPAM), whose solubility changes with the temperature of the solution An amylase (Dabiase) was immobilized on GMA-NIPAN under alkaline conditions The specific activity of Dabiase immobilized on GMA-NIPAM (D-GN) for saccharification of soluble starch was 90% that of native Dabiase and higher than that of conventional solid immobilized enzymes D-GN was soluble below 32°C but insoluble above 44°C When NaCl was added to a buffer solution (pH 50) with D-GN, the solubility response of D-GN to change in temperature was more sensitive than that in the buffer solution without NaCl In addition, the temperature causing half of the maximum turbidity decreased by about 23°C whenever the NaCl concentration of the buffer solution was increased by 1% D-GN was used successively for repeated hydrolysis reaction of soluble starch, in which D-GN was insolubilized not only by elevating the temperature of reaction mixture with 1% NaCl from 30°C to 38°C, but also by adjusting the NaCl concentration of reaction mixture to 4% at 30°C, followed by its batchwise recovery from a reaction product by centrifugation

37 citations


Journal ArticleDOI
TL;DR: In this paper, a continuous drying of a slurry of fine particles with water was carried out in a powder-particle fluidized bed, and its drying characteristics were examined.
Abstract: The powder-particle fluidized bed is a new type of fluidized bed developed to fluidize fine particles to prevent their agglomeration in the bed.Continuous drying of a slurry of fine particles with water was carried out in a powder-particle fluidized bed, and its drying characteristics were examined. Moisture in the slurry evaporated almost fully in the bed, and the moisture content of the exiting fine particles was nearly zero under the range of operating conditions in this study. Temperature and relative humidity of the outlet gas agreed with those calculated by mass and heat balances across the bed without knowledge of the rates of heat and mass transfer.

36 citations


Journal ArticleDOI
TL;DR: Sauter mean bubble sizes and size distributions on a number basis were determined photographically in the neighbourhood of a Rushton turbine impeller in this article, where four gases of molecular weights from 4 to 131 were used and deionized water and water saturated with carbon dioxide were used as the liquids.
Abstract: Sauter mean bubble sizes and size distributions on a number basis were determined photographically in the neighbourhood of a Rushton turbine impeller. To determine the effect of gas density, four gases of molecular weights from 4 to 131 were used and deionized water (coalescing) and water saturated with carbon dioxide (repressed coalescence) were used as the liquids. Very low gassing rates with impeller speeds just above the flooding-loading transition were used to allow an unobstructed light path for photography of a flat-bottomed vessel of 0.61 m diameter.All the bubble size distributions show positive skewness with most bubbles less than 0.2 mm in diameter. The Sauter mean is in the range of 0.35 to 0.7 mm. These sizes are smaller than have usually been reported because of the point of measurement. The Sauter mean diameters decrease with increasing impeller speed, but not as rapidly as implied by Kolmogoroffs theory of isotropic turbulence. The size also increases slightly with increasing gassing rate or molecular weight of gas.

34 citations



Journal ArticleDOI
TL;DR: In this article, a two-compartment cell separated by a cation exchange membrane and equipped with a titanium plate electrode was used to extract Trivalent Eu from an organic solution containing equal amounts of the three elements.
Abstract: The separation of Eu from Sm and Gd by combination of electrochemical reduction and solvent extraction was investigated. A two-compartment cell separated by a cation exchange membrane and equipped with a titanium plate electrode was used. Trivalent Eu was reduced to the divalent form by electroreduction in (NH4) 2SO4 aqueous solution containing SmCl3, EuCl3 and GdCl3 to form EuSO4 precipitate selectively. The purity of Eu in the precipitate was more than 97%. The electro-reductive stripping of Eu was studied by using a two-compartment electrochemical cell. In two-phase systems consisting of metal-loaded di-5-methyl-2-(1-methylneohexyl)neodecanoyl phosphoric acid (DP-18) or bis(2-ethylbexyl)phosphoric acid (D2EHPA) diluted with xylene and (NH4) 2SO4 aqueous solutions, Eu3+ was reduced at the aqueous phase/electrode interface and EuSO4 precipitated selectively in the aqueous phase. The recovery of Eu as EuSO4 from an organic solution containing equal amounts of the three elements was dependent on the aqueous-phase pH and attained up to 83.2% at pH 1.8 in the DP-18 system. The purity of Eu in the precipitate was more than 95%.


Journal ArticleDOI
TL;DR: In this paper, the influence of far-infrared irradiation on pasteurization of bacteria suspended in liquid medium below the lethal temperature was examined, and it was suggested that the test bacteria are injured and killed in the very thin domain near the surface of the suspension.
Abstract: The purpose of this study is to examine the influence of far-infrared irradiation on pasteurization of bacteria suspended in liquid medium below the lethal temperature. Under this condition, Escherichia coli and Staphylococcus aureus are injured and killed by far-infrared irradiation. With increase in irradiation power and with decrease in depth of the suspension, the ratio of the number of injured cells to the number of viable cells becomes higher, and the number of viable cells becomes smaller. Moreover, the pasteurization effect can be enhanced by raising the bulk temperature of the suspension. By estimating the temperature distribution within the suspension, it is suggested that the test bacteria are injured and killed in the very thin domain near the surface of the suspension.

Journal ArticleDOI
TL;DR: In this paper, a mathematical model was developed to describe the processes occurring during dead-end etectro-ultrafiltration, taking both electrophoretic and electroosmotic effects into account.
Abstract: Dead-end ultratiltration with application of a d.c. electric field to reduce membrane fouling rates was conducted under constant pressure using protein (bovine serum albumin) solution. When electric fields were applied, the filtration rate was significantly increased over that in ordinary dead-end ultrafiltration by both electrophorefic motion of the solutes away from the cake surface and electroosmosis occurring in the filter cake. The improvement in filtration rate becomes more pronounced with increasing electric field strength. In addition, effects of such processing variables as the solution concentration, the pH of solutions and the applied filtration pressure on the performance of dead-end electro-ultrafiltration were examined. A mathematical model was developed to describe the processes occurring during dead-end etectro-ultrafiltration, taking both electrophoretic and electroosmotic effects into account. The model accounted well not only for the dynamically balanced filtration rate but also for the variation in filtration rate with time.

Journal ArticleDOI
TL;DR: In this article, the experimental data were correlated by using the modified UNIQUAC equation to satisfy the chemical equilibrium condition as well as the vapor-liquid equilibrium condition, which was obtained from experimental data with chemical reaction equilibrium in the liquid phase of the quaternary system.
Abstract: The vapor-liquid equilibria with chemical reaction equilibrium of a quaternary system, acetic acid-ethanol-water-ethyl acetate, were measured in an equilibrium still by the static method The experimental data were correlated by using the modified UNIQUAC equation to satisfy the chemical equilibrium condition as well as the vapor-liquid equilibrium condition The UNIQUAC binary parameters were obtained from experimental vapor-liquid equilibrium data with chemical reaction equilibrium in the liquid phase of the quaternary system and existing equilibrium data for the six binary and the two ternary systems The correlations of both the vapor-liquid equilibrium and the chemical reaction equilibrium in the liquid phase were found to be in good agreement with the experimental data

Journal ArticleDOI
TL;DR: In this article, the influence of far-infrared irradiation on pasteurization of Escherichia coli and Staphylococcus aureus on or within a model for wet-solid food was studied.
Abstract: The present purpose is to study the influence of far-infrared irradiation on pasteurization of Escherichia coli and Staphylococcus aureus on or within a model for wet-solid food. Agar medium was used as the food model. By determining the thermal resistances of the test bacteria, the pasteurization effect of far-infrared irradiation (radiative heating) was compared with that of hot-air heating (a conventional method) from the viewpoint of thermal death kinetics. It was found experimentally that far-infrared irradiation is more effective than hot-air heating for the test bacteria on the agar-plate. Moreover, it is suggested that the surface temperature of the pasteurization sample irradiated by far-infrared radiation is higher than that measured by the thermocouples.

Journal ArticleDOI
TL;DR: In this paper, the authors applied the osmotic pressure model to predict the permeate flux value during reverse osmosis of a highly concentrated multi-solute solution such as fruit juice.
Abstract: To predict the permeate flux value during reverse osmosis of a highly concentrated multi-solute solution such as fruit juice, applicability of the osmotic pressure model, which takes into account the effect of the concentration polarization phenomenon on the permeate flux value, to a binary solute solution containing sucrose and glucose was evaluatedTo adapt the model to the highly concentrated binary solute solution, methods to estimate the dependence of density, viscosity, osmotic pressure, and solute diffusivity on the solute concentration were investigatedDefining the solution properties, the experimental permeate flux values agreed well with values calculated by the osmotic pressure model The model, which had been applied only for dilute solutions containing one component, was therefore able to predict precisely the permeate flux for the highly concentrated binary solute solution without using any fitting parameters

Journal ArticleDOI
TL;DR: In this paper, the operating conditions to provide surfaces free from micropyramids (MPs) were empirically determined for the case of preparing silicon thin diaphragms from 4-in. wafers for use as pressure sensors.
Abstract: Etch rates of (100) silicon wafers in KOH solutions were measured and correlated in a wide range of KOH concentration and solution temperature where etching proceeded anisotropically. The operating conditions to provide surfaces free from micropyramids (MPs) were empirically determined for the case of preparing silicon thin diaphragms from 4-in. wafers for use as pressure sensors. The relations between operating conditions and the presence of NIPS were shown diagrammatically in terms of KOH concentrations and temperatures, such as the findings that etched surfaces were smooth and free from MPs primarily at higher KOH concentrations and secondarily at higher temperatures. MP formation was assumed to be caused by silicon oxide precipitates existing in the wafers which dissolved in KOH solutions at rates much lower than the etch rates of silicon crystals under the operating conditions examined. In addition to these precipitates some silicon complexes and/or contaminants in the KOH solutions were also suggested to participate in NIP formation.

Journal ArticleDOI
TL;DR: The experimental conditions chosen and the baffle designs are believed to approach the hydrodynamic conditions of many commercial bubbling beds more closely than did earlier studies as discussed by the authors, and preliminary results describe the designs of experimental baffles and their impact on bubble growth.
Abstract: ABB Lummus-Crest initiated an experimental investigation to systematically study the capacity of baffles and internals (henceforth called baffles) of various designs to break bubbles in a moderately sized cold unit at reasonably high gas velocities. The experimental conditions chosen and the baffle designs are believed to approach the hydrodynamic conditions of many commercial bubbling beds more closely than did earlier studies. Preliminary results, describing the designs of experimental baffles and their impact on bubble growth, are presented


Journal ArticleDOI
TL;DR: In this article, the performance of asymmetric polyimide hollow-fiber membrane modules was investigated in a countercurrent flow pattern and in a both-end-opened pattern to investigate membrane performance and the effects of operating factors on membrane module responses.
Abstract: Vapor-permeation separation of water-ethanol mixtures by asymmetric polyimide hollow-fiber membrane modules was carried out in a countercurrent flow pattern and in a both-end-opened pattern to investigate membrane performance and the effects of operating factors on the membrane module responses. The specific permeability coefficient of water vapor for the fibers was about 4 × 10–7 mol/(m2·s·Pa) at 378K, which was about 500 times that of ethanol vapor. The experimental results of membrane module responses for enrichment of ethanol composition at feed outlet, XRE, up to 99.7wt% were in good agreement with the results calculated from a conventional model. The both-end-opened flow pattern was much superior to the countercurrent one, especially for high-level enrichment, because of reduced buildup of permeate pressure inside the hollow fibers. The calculation showed optimum inside diameter and length of the hollow-fibers, depending on XRE and feed-side pressure.

Journal ArticleDOI
TL;DR: In this article, the first example of cephalosporin extraction was presented, where the anion exchange reaction between cephorin C and acetate was observed in the stripping process, and tri-n-octylmethylammonium chloride and carbonate buffer were used as extractant and buffer, respectively.
Abstract: The decomposition rate of cephalosporin C was measured in order to determine the stable operating conditions for extraction, and the same pH dependence as those reported in the past works was obtained. The physical extraction of cephalosporin C with butyl acetate did not occur since it was amphoteric and the fraction of undissociated form was very low.The reactive extraction and strippting of cephalosporin C were studied by using various extractants and buffer solutions. The reactive extraction occurred when tri-n-octylmethylammonium chloride and carbonate buffer were used as an extractant and buffer, respectively. This was the first example of cephalosporin extraction. Cephalosporin C extracted into organic phase was stripped by acetate buffer solution. In the stripping, the anion exchange reaction between cephalosporin C and acetate occurred.

Journal ArticleDOI
Genji Jimbo1
TL;DR: In this article, chemical engineering aspects of the analysis of comminution process, mainly about energy laws and rate theory analysis, are reviewed, and the recent trend of the research works on the limit size by fine grinding, the existence of which has long been pointed out but with little experimental evidence.
Abstract: In this paper, chemical engineering aspects of the analysis of comminution process, mainly about energy laws and rate theory analysis, are reviewed. About the former, first the steps of the energy transfer process from the energy input into a mill to individual particles are discussed, and then the energy laws, which include the notion of limit product size, or limit specific surface area, are reviewed and discussed. About the latter, Alyavdin-Chujyo’s equation is investigated as an example of laws of rate theory, and from the conditions of holding this relation the theoretical basis of Rosin-Rammier’s equation is shown. Using these analytical methods, the final part of this paper reviews the recent trend of the research works on the limit size by fine grinding, the existence of which has long been pointed out but with little experimental evidence. Recently it has been confirmed experimentally and systematically, both in in-air and in-liquid grinding, as an equilibrium state between positive and negative, or reverse, grinding.

Journal ArticleDOI
TL;DR: In this article, a batch kinetic experiments were performed for adsorption of nitrobenzene and benzonitrile from aqueous solution onto activated carbon, the isotherms of which were only partially expressed by Freundlich equations.
Abstract: Batch kinetic experiments were performed for adsorption of nitrobenzene and benzonitrile from aqueous solution onto activated carbon, the isotherms of which were only partially expressed by Freundlich equations. The experiments were carried out with adsorbents which had been equilibrated with a certain concentration of the solution in advance, to obtain adsorption rates representing certain ranges of the amount adsorbed. The intraparticle mass transfer rate was confirmed to be dominated by surface diffusion through the determination of pore diffusivity using a non-adsorptive substance, while the external mass transfer resistance could not be neglected

Journal ArticleDOI
TL;DR: The volume of gel coating film was shown to be proportional to the mass of calcium ion initially contained in the core bead, and it was found that the thickness of Gel coating film could be controlled by adjusting the calcium concentration in thecore bead.
Abstract: Biocatalyst immobilization carrier was coated with calcium alginate gel by a two-step preparation procedure for prevention of leakage of the biocatalyst from the carrier. A uniform gel coating film could be formed around not only calcium alginate get beads but also chitosan beads. The thickness of calcium alginate gel coating increased with decreasing sodium alginate concentration and stirring rate, and with increasing concentration of calcium ion and diameter of the core bead. The volume of gel coating film was shown to be proportional to the mass of calcium ion initially contained in the core bead. It was also found that the thickness of gel coating film could be controlled by adjusting the calcium concentration in the core bead.

Journal ArticleDOI
TL;DR: The modified cellulase displayed a high stability of activity against temperature and pH and showed 30% greater conversion of filter paper as substrate at 90 h than in the case where native cellulase was used.
Abstract: Characteristics of modified cellulase with synthetic copolymers of polyethylene glycol alkylallylether and maleic acid anhydride were studied. Amino groups of the cellulase molecule were covalently coupled with the maleic acid anhydride functional group of the copolymer. The modification degree of the amino groups was controlled through the reaction process by changing the reaction time or the weight ratio of a synthetic copolymer to cellulase. As the modification degree increased, the activity of modified cellulase slightly decreased. At the maximum modification degree of 55%, the modified cellulase activity retained more than 90% of the unmodified native cellulase activity. The modified cellulase displayed a high stability of activity against temperature and pH. Finally it showed 30% greater conversion of filter paper as substrate at 90 h than in the case where native cellulase was used.

Journal ArticleDOI
TL;DR: In this paper, the solubilities of carbon dioxide in lauric acid, palmitic acid and arachidic acid have been measured in a semi-low apparatus over the temperature range from 373.2 K to 473.2K at pressures up to 5.07 MPa.
Abstract: The solubilities of carbon dioxide in lauric acid, palmitic acid and arachidic acid have been measured in a semiflow apparatus over the temperature range from 373.2 K to 473.2 K at pressures up to 5.07 MPa. A correlation is developed to describe the experimental data and to calculate the solubilities of carbon dioxide in these three heavy carboxylic acids. Henry’s constants and the partial molar volumes at infinite dilution of carbon dioxide are determined from the measured solubility data.

Journal ArticleDOI
TL;DR: In this paper, a pervaporation membrane consisting of polyacrylonitrile hollow fiber with a thin ionized cross-linking chitosan layer, developed for dehydration from aqueous organic mixture, was evaluated at the scale of a 6 m2 module under various conditions of feed composition (95 − 99.8 wt), temperature (40 − 75°C), and pressure (0.1 − 1.8 kPa).
Abstract: Performance of a pervaporation membrane consisting of polyacrylonitrile hollow fiber with a thin ionized cross-linking chitosan layer, developed for dehydration from aqueous organic mixture, was evaluated at the scale of a 6 m2 module under various conditions of feed composition (95–99.8 wt%), temperature (40–75°C) and pressure (0.1–1.8 kPa). The data indicate high performance of the module in both permeation rate and separation factor, 0.6 kg/(m2·h) and 5000 respectively at an ethanol concentration of 95 wt%.It was also shown that the permeation rates vary in proportion to the mole fraction of water in the feed to the power of 1.3, while the separation factor was almost constant in the range of ethanol concentration from 95 to 99.5 wt%. Under an operating pressure lower than the partial vapor pressure of water in the feed, the temperature dependence of the permeation rate follows the Arrhenius equation with an activation energy of 54 kJ/mol independently of the operating pressure.