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Showing papers in "Journal of Chemical Engineering of Japan in 1982"


Journal ArticleDOI
TL;DR: In this article, the pore model was modified in order to remove the discrepancy between these two models and remove the wall correction factors, and the data were reanalyzed by this new model, the "steric hindrance-pore model", and it became clear that this model adequately interpreted the experimental data.
Abstract: The friction model and the pore model were studied comparatively, and the latter was modified in order to remove the discrepancy between these two models Ultrafiltration data of six solutes of various molecular weights, obtained in our previous study, were analyzed by this model, but the results were not satisfactory Wall correction factors were then eliminated from the modified pore model The data were reanalyzed by this new model, the "steric hindrance-pore model", and it became clear that this model adequately interpreted the experimental data The values for membrane pore radius obtained were in good agreement The Ak/ΔX value for each solute calculated was almost constant, and agreed well with that determined from pure water permeation The reason why this proposed model, from which the usual wall effect is eliminated, works well is not clear at this stage

129 citations


Journal ArticleDOI
TL;DR: In this paper, the coagulation of colloidal particles in a simple shear flow of a viscous fluid is considered, and a kinetic equation is proposed in which the hydrodynamic interaction between particles is taken into account.
Abstract: The coagulation of colloidal particles in a simple shear flow of a viscous fluid is considered. The coagulation rate between unequal spherical particles is calculated by use of approximate trajectory equations, and a kinetic equation of shear coagulation is proposed in which the hydrodynamic interaction between particles is taken into account. It is found that the coagulation rate decreases rapidly with increase of the ratio of particles radius ai/aj and a dimensionless quantity 6πμa3ijγ/A. Comparison between the present theory and the classical Smoluchowski theory indicates that the Smoluchowski theory is applicable to limited coagulation systems and that it overestimates the coagulation rate considerably when applied to common aqueous dispersions. It is also found that the change of particle concentration is conveniently estimated by a kinetic equation in which the coagulation rate between unequal particles is approximated by that between equal spheres.

87 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of polyvinyl alcohol, added as a stabilizer to the continuous phase, on dispersed drop size distribution was investigated in suspension polymerization of styrene.
Abstract: Suspension polymerization of styrene was conducted to study the effect of polyvinyl alcohol, added as a stabilizer to the continuous phase, on dispersed drop size distribution. Transient drop size distributions were measured under several experimental conditions with dispersedphase volume fractions ranging from 0.1 to 0.5 and stabilizer concentrations from 0.3 to 10g/l. The experimental results show that at the early stage of the reaction, where the dispersed phase viscosity is lower than about 50 cp, drop size does not depend upon stabilizer concentration. Above this viscosity, stabilizer concentration influences on drop size. Whenever drop agglomeration occurs, drop size distribution reveals a bimodal form in which the lower drop size mode in the distribution maintains a constant drop diameter while the higher drop size mode moves toward a larger drop size. The experimental results may be accounted for by the hypothesis that the coalescence of dispersed drops above the maximum stable drop size for breakup is not effectively prevented by the stabilizer.

83 citations


Journal ArticleDOI
TL;DR: In this article, the extraction equilibria of copper and zinc with 2-ethylhexyl phosphonic acid mono-2-methylhexyl ester dissolved in w-heptane or toluene diluent were carried out at 303 K.
Abstract: Measurements of the extraction equilibria of copper and zinc with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester dissolved in w-heptane or toluene diluent were carried out at 303 K. It was found that the extractant (HR) is apt to dimerize in n-heptane diluent. It was clarified that copper and zinc are extracted according to the following equations, respectively, in the low concentration range of the metals. Cu2+aq+2(HR)2, org⇔CuR2•2HRorg+2H+aq Zn2+aq+1.5(HR)2, org⇔ZnR2•HRorg+2H+aqExtraction equilibrium constants, Ke, Cu = 1.0×10-4 and Ke, Zn=2.5×10-2 mol1/2/dm3/2 were obtained. From the above experimental results, it is seen that selective separation of copper and zinc is possible by solvent extraction with the extractant used in this study.

53 citations


Journal ArticleDOI
TL;DR: In this article, an experimental investigation was made of the mixing of liquids in a tank where the liquid jet was injected through a nozzle, defined as the time required to reduce the concentration variation within 1% of the mixed mean value and was measured by an impulse response.
Abstract: An experimental investigation was made of the mixing of liquids in a tank where the liquid jet was injected through a nozzle The mixing time was defined as the time required to reduce the concentration variation within 1% of the mixed mean value and was measured by an impulse response The circulation time was also obtained from the response curve It was found that in the circulation flow regime of mixing (Re>3 ×104) there exists an optimum nozzle depth for rapid mixing It ranges from the liquid surface level to three-quarters of the liquid depth when the liquid depth is equal to the tank diameter, and is the mid-depth of the liquid when the liquid depth is smaller than the tank diameter When the nozzle height is within one-fourth of the tank diameter, it is efficient for rapid mixing to tilt the nozzle upwards enough to prevent the formation of a wall jet, which induces circulations of small variance of circulation time

42 citations


Journal ArticleDOI
TL;DR: In this paper, the optimum geometrical variables for the mixing process are provided and the results explained by considering the relation between the mixing pattern and impeller geometry, and a mathematical model is developed and applied in order to correlate the measure mixing times.
Abstract: Mixing patterns in agitated vessels equipped with various types of helical ribbon impellers are observed by using capsules of liquid crystal as a tracer. As a result, the optimum geometrical variables for the mixing process are provided and the results explained by considering the relation between the mixing pattern and impeller geometry. A mathematical model is developed and applied in order to correlate the measure mixing times.

35 citations


Journal ArticleDOI
TL;DR: In this paper, the rejection characteristics of macromolecular gel layer for low-molecular weight solutes were studied by ultrafiltration using o¥ albumin and polyvinyl alcohol, which formed a gel layer, and vitamin B12, raffinose and glucose, which were rejected by the gel layer.
Abstract: Rejection characteristics of macromolecular gel layer for low-molecular weight solutes were studied by ultrafiltration using o¥ albumin and polyvinyl alcohol, which formed a gel layer, and vitamin B12, raffinose and glucose, which were rejected by the gel layer. The bilayer membrane model and the Jagur-Grodzinski and Kedem equations were found effective in analyzing the rejection ability of the gel layer, which was defined by two parameters, σg and Pg. These parameters could be determined by the curve-fitting method. Furthermore, σg and Pg were analyzed by use of the steric hindrance-pore model, and the structure of the gel layer was estimated. It became clear from the experimental results that compaction of the gel layer by mechanical pressure occurred and affected the rejection ability. This effect can be calculated by taking into the pressure dependencies of thickness and pore radius of gel layer.

35 citations


Journal ArticleDOI
TL;DR: In this paper, a method was developed to determine the dependence of surface diffusion coefficient on the amount adsorbed, derived for Freundlich adsorption isotherm, from adsoreption rates in a finite bath.
Abstract: A method is developed to determine the dependence of surface diffusion coefficient on the amount adsorbed, derived for Freundlich adsorption isotherm, from adsorption rates in a finite bath. The adsorption rates on activated carbon of p-nitrophenol, benzoic acid and p-chIorophenol from dilute aqueous solutions are measured, where Freundlich adsorption isotherms are applicable, and the relations between surface diffusion coefficient and the amount adsorbed are determined for three adsorbates by this method. It is proved that the external mass transfer resistance in the stirred tank has a large influence on adsorption rate as well as intraparticle mass transfer resistance in finite bath adsorption. It is also clear from these relations that the ratio of activation energy for surface diffusion to adsorption energy is nearly equal to 0.5. The time-concentration curves predicted by this method coincide well with experimental data.

32 citations



Journal ArticleDOI
TL;DR: In this article, the thermal conductivities of 10 pure liquid alcohols and four of their binary mixtures were measured by using the relative horizontal parallel-plate method (steady-state type) under atmospheric pressures.
Abstract: The thermal conductivities of ten pure liquid alcohols and four of their binary mixtures were measured by use of the relative horizontal parallel-plate method (steady-state type) under atmospheric pressures Measurements for pure alcohols were carried out at temperatures from 20 to 70°C and for binary mixtures at 250 and 500°C A previous correlation model developed for the thermal conductivities of nonpolar liquids on the basis of the lattice model coupled with the hole theory concept has been successfully extended to polar liquids such as alcohols by the introduction of a new empirical parameter to represent the polar effect Reduced values of the potential parameters and the empirical parameter, needed in the calculation of thermal conductivities, could be correlated by quadratic functions of Pitzer''s acentric factor and Stiel''s polar factor The present model is also extended to alcohol mixtures by use of binary interaction parameters

30 citations


Journal ArticleDOI
TL;DR: In this paper, a gas-liquid-solid fluidized bed of 0.12 m i.d. was analyzed on the basis of the circulating flow model, where a constant turbulent viscosity and a constant composition of the liquid-solid mixtures were assumed.
Abstract: Axial and radial distributions of gas holdup and liquid velocity were studied in a gas-liquid-solid fluidized bed of 0.12 m i.d. Air, water and glass beads (0.58, 1.2 and 2.2 mm in diameter) were used as gas, liquid and solid particle phases, respectively. Local gas holdup was meaured by using an electric conductivity probe, and local liquid velocity was obtained by the electrolyte tracer method. The value of local gas holdup was in proportion to the square of the distance from the column wall. The liquid flow pattern was similar to that of the bubble column, showing an up-flow in the central region and a down-flow in the peripheral region with respect to the interstitial mean liquid flow. Liquid velocity at the central axis increased with increasing superficial gas velocity and with decreasing particle diameter. The results were analyzed on the basis of the circulating flow model, where a constant turbulent viscosity and a constant composition of the liquid-solid mixtures were assumed. The turbulent viscosity for fully developed fluidization was correlated as a function of particle diameter and superficial gas velocity, and was compared to that of the bubble column.

Journal ArticleDOI
TL;DR: In this article, a method of particle size distribution measurement using a fluidization curve was developed and the size distributions observed in binary and tertiary mixtures were in agreement with those by microscopic measurement.
Abstract: A method of particle size distribution measurement using a fluidization curve is developed. The size distributions observed in binary and the tertiary mixtures were in agreement with those by microscopic measurement. For those mixtures the apparent minimum fluidizing velocity, if the particles were completely segregated, us, determined by Us=(ΣWi/Woumfi)-1where Wi/Wo is the weight fraction corresponding to umfi. The values calculated from the above expression were in good agreement with the experimental data. The main disadvantage of this method is that, in the fluidization bed, the terminal velocity of the minimum-diameter particle must be less than the fluidizing velocity of the maximumdiameter particle, and the measurable size ratio (xmax/xmin) is 8-10.

Journal ArticleDOI
TL;DR: Takahashi and Takahashi as discussed by the authors used the modified Enskog-Thorne theory to calculate diffusion coefficients at high pressure using T9 and SB3 charts, and showed that the T chart is in better agreement than the SB chart in the lower-pressure (P <100x 105 Pa) region, and SB chart is better in the higher-pressure region.
Abstract: normal ethylene) at atmospheric pressure, which could not be found in the literature, were obtained from Figs. 1 to 4 by extrapolation and correction for molecular weights. As can be seen from Table 2, the values obtained from the 14CO2 (trace)-C2H4 system are in good agreement with those obtained from the 14C2H4 (trace)-CO2 system. This agreement is experimental support for the first approximation derived from theories that binary diffusion coefficients do not depend on the proportion of mixtures2}. Diffusion coefficients at high pressures were calculated using T9) and SB3) charts. As can be seen from Figs. 1 and 2, the T chart is in better agreement than the SB chart in the lower-pressure (P<100x 105 Pa) region, and the SB chart is better in the higherpressure region. Diffusion coefficients calculated using the modified Enskog-Thorne theory are shown in Figs. 3 and 4. The compressibility factors and the second and third virial Received June 4, 1981. Correspondence concerning this article should be addressed to S. Takahashi. Shinji TAKAHASHIand Masaru HONGO Chemical Research Institute of Non-aqueous Solutions, Tohoku University, Sendai 980

Journal ArticleDOI
TL;DR: In this article, a dye-sensitized photodegradation of aqueous phenol using rose bengal was carried out batchwise in the chemical region by using an annular bubble-column photoreactor, to evaluate the use of sunlight in wastewater treatment.
Abstract: The dye-sensitized photodegradation of aqueous phenol using rose bengal was carried out batchwise in the chemical region by using an annular bubble-column photoreactor, to evaluate the use of sunlight in wastewater treatment. Effects of both the partial pressure of oxygen and the initial concentration of phenol, [A]0, on the initial reaction rate were analyzed according to the reaction scheme including the quenching reaction of triplet dye 3D* with phenol, in order to determine the kinetic parameters. The reaction rate constant of phenol with singlet oxygen increased with increasing pH and was 2.66 ×108 dm3/mol-s at pH 10.3. The reaction quantum yield at pH 10.3 was limited to a maximum of 0.29 at [A]0=3 ×10-3 mol/dm3 for O2-bubbling and 0.13 at [A]0=1.4 ×10-3 mol/dm3 for air-bubbling by the quenching reaction of 3D* with phenol, of which the rate constant was 4.0×108 dm3/mol• s. p-Benzoquinone, the primary main product, underwent further degradation with both alkaline and ground-state oxygen to yield final products such as carboxylic acids. The reaction curves were simulated closely up to high conversions by taking account of the quenching effect of both phenol and the quinone-type intermediate products on 3D*.



Journal ArticleDOI
TL;DR: In this paper, the Dubinin-Astakhov (D-A) equation is modified for adosrption of gases on microporous activated carbons with appreciable size distribution of micropores.
Abstract: The Dubinin-Astakhov (D-A) equation is modified for adosrption of gases on microporous activated carbons with appreciable size distribution of micropores. Parameters n and E involved in the D-A equation are assumed to vary with the ratio of micropore size to molecular size of adsorbate. Also, E is considered to be in proportion to the standard heat of vaporization of the adsorbate. The dependence of n and E on these characteristics is determined from adsorption data for carbon molecular sieves that have uniform micropores. Thus, once the size distribution function of micropores is given for a commercial activated carbon, adsorption equilibrium of any gas is predictable with the generalized D-A equation proposed here by accounting for the micropore size distribution.

Journal ArticleDOI
TL;DR: In this paper, a dynamic NAD recycling method was proposed, in which native NAD, without immobilization, was dynamically recycled in continuous operation by immobilized conjugated enzymes (alcohol dehydrogenase and lactate dehydrogenases).
Abstract: Dynamic NAD recycling, in which native NAD, without immobilization, was dynamically recycled in continuous operation by immobilized conjugated enzymes (alcohol dehydrogenase and lactate dehydrogenase), was investigated experimentally. The results were compared with the theoretical model calculations in the preceding paper. Although there were some quantitative differences, the theoretical model could explain the experimental results at various operating conditions. Under a properly selected operating condition, a high NAD recycle number (6180) as well as a satisfactory conversion (34.6 %) of the limiting substrate was obtained experimentally. The operational stability of the present system was fairly good, retaining 70 % of its original activity after one month''s continuous operation. Compared with the immobilized-NAD method, the dynamic NAD recycling method is simple and is free from the problem of coenzyme inactivation during continuous operation. The experimental results obtained here showed the practicability of dynamic NAD recycling.

Journal ArticleDOI
TL;DR: In this article, the effects of the kinematic viscosity and surface tension of aqueous solution on the gas entrainment rate of an impinging liquid jet were studied experimentally, using a straight cylindrical nozzle with a nozzle cap.
Abstract: The effects of the kinematic viscosity and the surface tension of aqueous solution on the gas entrainment rate of an impinging liquid jet were studied experimentally, using a straight cylindrical nozzle with a nozzle cap. The three critical jet velocities at three transition points, respectively, on the gas entrainment curve increase with an increase of kinematic viscosity of the liquid. The gas entrainment rate of an impinging liquid jet tends to decrease in the initial entrainment region, while it tends to increase in the low jet velocity region, as kinematic viscosity increases. In the high jet velocity region, the effect of kinematic viscosity on gas entrainment rate is insignificant. The effect of the surface tension of the liquid on the gas entrainment rate and the three transition points is negligible.

Journal ArticleDOI
Son-Ki Ihm1, Sung-Sup Sum1, In-Hwan Oh1
TL;DR: In this article, a model is proposed for a macroreticular resin catalyst to give the overall effectiveness factor in terms of the micro and macro-effectiveness factors and the fraction of the surface layer active sites.
Abstract: A model is proposed for a macroreticular resin catalyst to give the overall effectiveness factor in terms of the micro- and macro-effectiveness factors and the fraction of the surface layer active sites. Different values of the fraction can represent some possible cases of porous catalysts; i.e., a single or uniform pore and a bidisperse pore structure.


Journal ArticleDOI
TL;DR: In this paper, a vibratory plate separator was used to separate spherical and non-spherical particles according to shape, which is quite different from the apparatus in the works referred to above.
Abstract: Powdershape separators have been reported in the literature. For example, Carpenter et aU\\ Riley2} and Sugimoto et a/.3'4>6) have tried to separate mixtures of spherical and non-spherical particles by use of rotarydisc separators. Waldie7) has separated more spherical particles from mixtures of particles of different shapes by using a rotating tube. In this work, separation of particles according to shape was carried out by meansof a vibratory plate separator, which is quite different from the apparatus in the works referred to above.

Journal ArticleDOI
TL;DR: In this paper, a single helical ribbon impeller, SH6', was used to measure the power consumed around the arms which support the blades of the blades and the experimental procedure was described as described in the previous paper.
Abstract: The general configuration of a helical ribbon impeller is shown in Fig. 1 and the geometrical variables of the impellers used are summarized in Table 1. In addition to these impellers, a special single helical ribbon impeller, SH6', was used to measure the power consumed around the arms which support the blades. This impeller had the same geometry as the SH6 with an additional six arms. The experimental procedure was as described in the previous paper12K

Journal ArticleDOI
TL;DR: The liquid phase mixing pattern and dispersion coefficients were studied by the tracer concentration distribution at steady state and the impulse response method for the gas-liquid jet reactor with liquid jet ejector in this article.
Abstract: The liquid-phase mixing pattern and dispersion coefficients were studied by the tracer concentration distribution at steady state and the impulse response method for the gas-liquid jet reactor with liquid jet ejector. The longitudinal liquid-phase mixing pattern was quite different between the spouting section and the calm section. In the spouting section, which was the lower region in the column, the liquid phase was regarded as almost completely mixed flow. By contrast, in the calm section, which was the upper region, the value of the dispersion coefficient was fairly smaller than that in bubble columns and back-mixing of the liquid phase was suppressed.

Journal ArticleDOI
TL;DR: In this paper, a generalized model for axisymmetric free jets which allows for change in fluid density with temperature is proposed by experiment, and the radial profiles of velocity and temperature in the fully developed region can be expressed by the isothermal formulation using the corresponding jet half-radii as the characteristic radial distance.
Abstract: A generalized model for axisymmetric free jets which allows for change in fluid density with temperature is proposed by experiment. Experimental work was carried out to obtain data on jet velocity and temperature variations over a wide range of jet-to-ambient fluid density ratio (i.e. the initial density ratio) by use of nonisothermal free jets of burned gas exhausting into quiescent air as well as isothermal free jets of CO2-air mixture into air. Core lengths of velocity and temperature can be correlated as a function of initial density ratio and jet Reynolds number. The radial profiles of velocity and temperature in the fully-developed region can be expressed by the isothermal formulation using the corresponding jet half-radii as the characteristic radial distance. The jet half-radii and centerline decays can be described by new characteristic streamwise coordinates which take into account the effects of core length and initial density ratio. If the initial condition at the nozzle exit is specified, the present model can determine the radial distributions of velocity and temperature at any axial position.

Journal ArticleDOI
TL;DR: In this paper, the characteristics of bipolar packed-bed electrodes were studied by using copper deposition reaction from a copper sulfate solution. Ferrite pellets were used as a particulate phase and were packed in three kinds of mode.
Abstract: The characteristics of bipolar packed-bed electrodes were studied by using copper deposition reaction from a copper sulfate solution. Ferrite pellets were used as a particulate phase and were packed in three kinds of mode. The Faradaic current in the particulate phase, the by-pass current in the electrolyte phase and the short-circuiting current were measured separately. The minimum bipolar cell voltage was a function of decomposition voltage, distance between two plate electrodes, pellet diameter, and solid holdup. For regularly packed bipolar electrodes, the interaction between Faradaic and by-pass current was small, and a simplified parallel current model is proposed. For randomly packed bipolar electrodes, the interaction was not negligible at higher cell voltages. The minimum value of energy consumption was observed at a particular cell voltage which was a function of pellet size and packing mode. Because of increase in the short-circuiting current due to copper deposition, the energy consumption in the randomly packed bed increased with increase in electrolysis time. The regularly packed bed where the direction of current was parallel to the plain faces of the pellets was found to be the most efficient under the present experimental conditions.

Journal ArticleDOI
TL;DR: In this paper, simultaneous absorption of NO2 and NO into alkaline solutions was studied in a wide range of gaseous concentrations, NO2 from 5 to 2000 ppm and NO from 0.066 to 1.2%.
Abstract: Simultaneous absorption of NO2 and NO into alkaline solutions was studied in a wide range of gaseous concentrations, NO2 from 5 to 2000 ppm and NO from 0.066 to 1.2%. The absorption rate was not dependent on the concentration of hydroxide ion in the solution, if the alkalinity in the vicinity of the interface was maintained. In the presence of NO in excess of NO2, the stoichiometry of the absorption is expressed by the reaction NO+NO2+2OH-→2NO2-+H2O and the rate is proportional to the product of the interfacial concentrations of NO2 and NO. The predominant mechanism is considered to be the solution of N2O3 in equilibrium with NO and NO2 at the interface followed by its rapid hydration. The absorption rate is expressed by H√k2D [N2O3]G, H√k2D being 2.55 m•s-1, which is about two orders of magnitude greater than the corresponding value for the absorption of N2O4.

Journal ArticleDOI
TL;DR: In this paper, the volume and charge of water drops formed in a uniform electric field (0-4 kV/cm) have been measured in cyclohexane, toluene, insulating oil and three kinds of silicone oils as continuous phase.
Abstract: Volumes and charges of water drops formed in a uniform electric field (0-4 kV/cm) have been measured in cyclohexane, toluene, insulating oil and three kinds of silicone oils as continuous phase. Effects of nozzle length extended from an electrode, flow rate of dispersed phase and liquid viscosity of continuous phase on the volume and the charge are examined. Experimental values are compared with those calculated by equations presented. It is clarified that experimental volumes of the drops formed in a liquid having viscosity up to ten centipoises can be predicted by the presented equation. The experimental drop charges at low flow rates of dispersed phase are also represented by the equation. In a range of high flow rates of dispersed phase, however, a sudden decrease of charge has been observed.

Journal ArticleDOI
TL;DR: In this article, an experimental study of vapor-phase sensible heat and mass fluxes in ternary distillation of the methanol-ethanol-water system was made with a wetted-wall column at total reflux conditions.
Abstract: Experimental study of vapor-phase sensible heat and mass fluxes in ternary distillation of the methanol-ethanol-water system was made with a wetted-wall column at total reflux conditions. From heat and mass balances for the liquid film, a theoretical expression was derived for the interfacial velocity caused by mass fluxes. The interfacial velocity was shown to be a function of the sensible heat and diffusion fluxes. Observed vapor-phase sensible heat fluxes showed good agreement with the theoretical values obtained by laminar flow theories. Observed vapor-phase diffusion fluxes obtained from mass flux measurements also showed good agreement with the theoretical values, but a poor correlation was obtained for vapor-phase mass fluxes. Observed interfacial velocities were compared with the calculated values.