Showing papers in "Journal of Chemical Engineering of Japan in 1981"
TL;DR: In this article, the rejection of six solutions of various molecular weights by cellulose acetate ultrafiltration membranes was studied, and a method of curve-fitting was found effective to determine two parameters, i.e., solute permeability P and reflection coefficient σ.
Abstract: To establish an effective method of quantitative analysis in ultrafiltration, the rejection of six solutions of various molecular weights by cellulose acetate ultrafiltration membranes was studied. At first, the effects of concentration polarization were corrected. Mass transfer coefficients determined by the velocity variation method agreed very well with the Deissler correlation. Next, by using Spiegler and Kedem equations, transport of solute through ultrafiltration membrane was analyzed. A method of curve-fitting was found effective to determine two parameters, i.e. solute permeability P and reflection coefficient σ. Finally, these parameters obtained from experiments for various solutes were analyzed using the modified "pore theory", and were correlated with the ratio of the radius of solute and pore and with the effective pore length. Structure of the membrane was estimated from these results.
198 citations
71 citations
TL;DR: In this paper, the flow transition from uniform bubbling regime to liquid circulation regime was studied in a vertical two-dimensional bubble column with no net liquid flow and a regular two-loop liquid circulation was observed to occur as a result of violent interactions of unsteady liquid circulation and large bubbles.
Abstract: The flow transition from uniform bubbling regime to liquid circulation regime was studied in a vertical two-dimensional bubble column with no net liquid flow. A regular two-loop liquid circulation was observed to occur as a result of violent interactions of unsteady liquid circulation and large bubbles. A critical superficial gas velocity was defined as the velocity at the point of incipient regular circulation and was obtained from the gas velocity at maximum gas hold-up. Under a uniform stable gas distribution the critical gas velocity depends on the ungassed liquid height and is independent of sparger geometry, i.e., the diameter and pitch of holes. When the pressure drop through the sparger is insufficient or inlet gas is distributed in the narrow central region of the sparger, interactions of large-scale liquid motions and large bubbles in the bulk section is suppressed by depleting the growth of large bubbles at the base. This makes the critical gas velocity larger than that under the uniformly sparged condition. A similar dependence of critical gas velocity on ungassed liquid height was confirmed with literature data for three-dimensional bubble columns.
61 citations
TL;DR: In this paper, correlative equations for kLa valid for a wide range of operating conditions are proposed based on the finding that the bubbling-controlling condition, the agitation-cont controlling condition, or the intermediate condition may predominate in an aerated mixing vessel.
Abstract: Based on the finding that the bubbling-controlling condition, the agitation-controlling condition, or the intermediate condition may predominate in an aerated mixing vessel, correlative equations for kLa valid for a wide range of operating conditions are proposed. In addition, the type of mixing of the gas phase in aerated mixing vessels is discussed, and plug-flow type mixing is recommended since the logarithmic mean value of entrance and outlet compositions of gas gives a reasonable gas absorption rate.
57 citations
TL;DR: In this paper, a mass transfer model for the extraction of amine in W/O/W emulsion systems having internal aqueous HCl solution phase is presented, which takes into account the diffusion in w/O emulsion drops as well as the external mass transfer around the emulsion drop, and the effect of various parameters on the extraction rate is clarified.
Abstract: A mass transfer model for the extraction of amine in W/O/W emulsion systems having internal aqueous HCl solution phase is presented which takes into account the diffusion in W/O emulsion drops as well as the external mass transfer around W/O emulsion drops, and the effect of various parameters on the extraction rate is clarified. Experimental data on the extraction of aniline, p-and m-toluidine by W/O/W emulsion systems using a batch-type agitation vessel is discussed on the basis of the present model. It is found that the model can explain the tendency of the experimental data. The mass transfer mechanism in W/O emulsion drops is discussed on the basis of the experimentally evaluated value of effective diffusivity in W/O emulsion drops.
49 citations
TL;DR: In this article, a unit cell model was developed after due consideration of particle diameter ratio and it was assumed that the coordination number was a function of diameter and volume fraction of components.
Abstract: The effective thermal conductivity was investigated for granular beds of various binary mixtures. Samples used were two or three sizes of glass beads, resin particles and copper spheres respectively. A unit cell model was developed after due consideration of particle diameter ratio and it was assumed that the coordination number was a function of diameter ratio and volume fraction of components. Predicted values coincided with experimental ones, in which the ratio of diameters was 1-2.8 and the ratio of solid conductivities was 1-5.8, within 6% deviation.
49 citations
TL;DR: In this paper, the authors measured the properties of silica sand particles with mean sizes 0.3, 0.45 and 0.6 mm fluidised by air under pressures from 0.1 to 0.8 MPa.
Abstract: The behaviour of silica sand particles with mean sizes 0.3, 0.45 and 0.6 mm fluidised by air under pressures from 0.1 to 0.8 MPa was observed in a transparent two-dimensional bed. Minimum fluidisation velocity, bed expansion and bed height fluctuation were measured by the usual methods, bubble characteristics such as the size, rising velocity and frequency by cine-photography. The minimum fluidisation velocity decreased with pressure, explainable by considering the increase of the turbulent flow contribution to bed pressure drop, and fairly well described by the Wen and Yu correlation. No virtual effect of pressure on bubble size was observed but bubble shape became flattened, which in turn accompanied a decrease in the bubble rise velocity. Based on these results, the increased bed expansion and the unchanged bed fluctuation could be consistently explained.
42 citations
TL;DR: In this paper, the self-decomposition of ozone in water, the decomposition of CN- and CNO-, and the decolorization of several dyes by ozone were performed over a wide range of pH using a stopped-flow apparatus under homogeneous conditions at 298 K.
Abstract: Kinetic studies on the self-decomposition of ozone in water, the decomposition of CN- and CNO-, and the decolorization of several dyes by ozone were performed over a wide range of pH using a stopped-flow apparatus under homogeneous conditions at 298 K. The rate of selfdecomposition of ozone was measured in the pH range from 1 to 13.5, and it was found that in the pH range above 8 the rate was expressed by -d[03]/dt=314 [03] [OH-]0.88while in the acidic region the concentration dependence of the rate was complicated, and a simple rate expression could not be obtained. The rate of decomposition of CN- by ozone was expressed by -d[CN-]/dt=310 [O3]0.8 [CN-]0.55 (9.4
40 citations
TL;DR: In this paper, a two-region model is applied to Newtonian liquids with various physical properties and to non-Newtonian liquids, and reasonable dimensionless correlative equations are obtained.
Abstract: Aerated mixing vessels are often used in chemical and biological industries. When the rate of gas absorption controls the rate of reactions, kLa is used as the design standard. It was previously reported by the present authors that the overall vessel condition varied from bubbling-controlling condition at relatively high gas rates to agitation-controlling condition at relatively high impeller speeds via intermediate condition. According to this two-region model, kLa for the airwater system in the aerated mixing vessel has been correlated well in a wide range of operational conditions. In this report, the two-region model is applied to Newtonian liquids with various physical properties and to non-Newtonian liquids, and reasonable dimensionless correlative equations are obtained.
40 citations
TL;DR: In this paper, the authors studied the entrainment of solid particles from a gassolid fluidized bed by following the rise of bubbles and measuring the velocity of particles leaving the bed surface.
Abstract: Entrainment of solid particles (Glass beads, dp=300-600 μm, Umf=14 cm/s) from a gassolid fluidized bed was studied experimentally by following the rise of bubbles and measuring the velocity of particles leaving the bed surface. Photographs of the freeboard were taken continually to follow the particle movement in it. Based on analysis of these data, it was found that the particles in the wake for an isolated bubble scarcely contributed to entrainment but that bubble coalescence near the bed surface was the key factor in entrainment. Bubble bursting behavior was classified into four patterns:(I) Isolated bubble(II) Successively rising bubbles(III) Coalescent bubble(IV) Successively coalescent bubbles For the first two groups, the particle velocity leaving the bed surface was usually less than the bubble rising velocity and for the latter two, it exceeded the bubble rising velocity.
39 citations
TL;DR: In this paper, up to four multiple steady states were experimentally observed by hydrogenating cyclohexene on a Pt/Al2O3 catalyst having bimodal distribution.
Abstract: Up to four multiple steady states were experimentally observed by hydrogenating cyclohexene on a Pt/Al2O3 catalyst having bimodal distribution. The catalyst, in the form of 3/16-in. by 3/16-in. cylindrical pellet containing 5.6 wt% platinum on γ-alumina support, was imbedded in a bed of inert α-alumina pellets of similar size to isolate the effect of individual catalyst pellet, and was surrounded by reacting mixture containing saturated cyclohexene vapor. The reaction was run at four different temperatures, i.e. 15, 22, 30 and 40°C, and as a means of changing reaction condition at a given reaction temperature the hydrogen partial pressure was varied. From experimental evidence, two of these multiple steady states were interpreted as the rates in vaporfilled and liquid-filled catalyst pores and the other two steady states as those of pores with different degrees of liquid filling. The transition of phase was apparent from sharp change in observed reaction rate.
TL;DR: The charge of aerosols generated by various methods was measured by a visual experimental technique as mentioned in this paper, and the results obtained are as follows: 1) Aerosol particles generated by condensation after evaporation almost reach the Boltzmann charge distribution when ions are mixed as condensation nuclei, but have a lower charge when no ions were mixed.
Abstract: The charge of aerosols generated by various methods was measured by a visual experimental technique. The results obtained are as follows: 1) Aerosol particles generated by condensation after evaporation almost reach the Boltzmann charge distribution when ions are mixed as condensation nuclei, but have a lower charge when no ions are mixed. 2) The charge of aerosol particles generated by chemical reaction depends on the aerosol material and the kinds of reaction. Metal aerosol particles generated by combustion are highly charged, but particles of tobacco smoke are not highly charged. Aerosol particles of ammonium chloride generated by chemical reaction, on the other hand, are not charged at all. 3) The charge of aerosols dried after atomization seems to be affected by the state of solution or suspension in nebulizer. Di-octyl sebacate particles are almost uncharged, sodium chloride particles are highly charged, and polystyrene latex particles have the highest charge among the aerosols tested. 4) Aerosols generated by mechanical dispersion have a charge higher than the Boltzmann charge.
TL;DR: In this article, an apparatus was designed and constructed for high-pressure vapor-liquid equilibrium in the temperature range -50°C to 50°C at pressures up to 100 atm.
Abstract: An apparatus is newly designed and constructed for investigation of high-pressure vapor-liquid equilibrium in the temperature range -50°C to 50°C at pressures up to 100 atm. The visual type of static apparatus is distinguished by the inclusion of a specially designed sampling device for liquid phase to reduce experimental error during the sampling, and of a magnetically driven agitator by which the vapor phase is dispersed into the liquid phase within the cell. Using this apparatus, the binary vapor-liquid equilibrium data for the ethylene-propylene system at -10.08°, 0.07°, 10.07° and 20.14°C, and ethylene-1-butene at -0.01°, 10.01° and 20.20°C are measured. The data obtained are correlated by using three equations of state. The predicted results are in good agreement with the experimental data except in the region close to the critical point.
TL;DR: In this article, the authors measured drift lines produced after a single bubble passage in a 0.19 m i.d. three-dimensional gas-fluidised bed of 0.163 mm glass beads which contains tiny but recognizable aggregates of jetsam particles or bulk particle tracers.
Abstract: Drift lines produced after a single bubble passage were measured in a 0.19 m i.d. three-dimensional gas-fluidised bed of 0.163 mm glass beads which contains tiny but recognizable aggregates of jetsam particles or bulk particle tracers. Lateral distributions of the descending distance of jetsam relative to the bulk particles were obtained from the difference between the jetsam and the bulk drift lines, and were then reduced to the average descending distance over the bubble cross-sectional area. The segregation rate constants were calculated for four kinds of jetsam, fairly larger or denser than the bulk particles, and were applied to the estimation of jetsam concentration profiles based on an existing mathematical model. The results of comparison of the estimated concentration profiles with those observed by other investigators were quite satisfactory, indicating that the experimental results here obtained are reliable.
TL;DR: Gluconobacter suboxydans was cultivated in a fed-batch culture with a DO-stat under the condition that none of the components in the basal medium limited the growth of the microorganism and the production of sorbose as mentioned in this paper.
Abstract: Gluconobacter suboxydans was cultivated in a fed-batch culture with a DO-stat under the condition that none of the components in the basal medium limited the growth of the microorganism and the production of sorbose. Final concentration of sorbose reached 460 g/l after 16 hrs with CSL medium and 628 g/l after 14 hrs with YE medium, respectively. Conversion ratio of sorbitol to sorbose was almost maintained at about 0.9 for CSL medium and about 1.0 for YE medium during the cultivation. The effect of sorbose concentration on growth was investigated in test tube culture. Decrease in specific growth rate and a lag phase were observed with increase in sorbose concentration in culture medium. The growth was inhibited considerably at 300 g/l of sorbose concentration and was not observed at sorbose concentrations over 510 g/l. The effect of osmotic pressure and water activity on growth was examined. Growth rate and sorbose production rate decreased as osmotic pressure increased or water activity decreased due to the accumulation of sorbose.
TL;DR: In this paper, the authors measured the rate of mass transfer from liquid phase to small particles (average diameter, 0.46-1.3 mm) by use of ion exchange reaction followed by instantaneous irreversible reaction at 30°C.
Abstract: Rates of mass transfer from liquid phase to small particles (average diameter, 0.46-1.3 mm) were measured by use of ion-exchange reaction followed by instantaneous irreversible reaction at 30°C. Nitrogen gas and dilute aqueous solution of sodium hydroxide were fed into a shallow bed packed with a strong cation exchange resin. Volumetric mass transfer coefficients for gasliquid cocurrent upflow and downflow were almost identical at the same gas and liquid flowrates but became somewhat greater than those in liquid-full single phase flow. A unified correlation could be derived by arranging experimental data for three arrangements: liquid-full single phase flow, gas-liquid cocurrent upflow and downflow (trickle-bed).
TL;DR: In this paper, the surface flow of hydrocarbons, such as ethylene, propylene and isobutane, through activated alumina at 10°C and 30°C was measured over a mean pressure level range of a few kPa to about 100kPa using a permeation apparatus.
Abstract: Surface flow of hydrocarbons, such as ethylene, propylene and isobutane, through activated alumina at 10°C and 30°C is measured over a mean pressure level range of a few kPa to about 100kPa using a permeation apparatus. The surface flow coefficient is also determined as a function of amount adsorbed and temperature. The dependence of the surface flow coefficient on the above quantities can be well correlated using the random hopping model previously proposed by the authors. In addition, data from the literature for three other systems are correlated by this model.
TL;DR: In this paper, the behavior of bipolarly charged aerosol particles undergoing electrostatic coagulation was studied from both theoretical and experimental points of view, and the population balance equation for the behaviour of the charged particles was numerically solved for aerosol having various initial charge distributions.
Abstract: The behavior of bipolarly charged aerosol particles undergoing electrostatic coagulation was studied from the theoretical and experimental points of view. The population balance equation for the behavior of the charged particles which includes the simultaneous effects of electrostatic coagulation, electrostatic diffusion and Brownian coagulation was numerically solved for aerosol particles having various initial charge distributions. As a result, the time-dependent changes in particle number concentration and charge distribution under the effects of electrostatic coagulation, electrostatic diffusion and Brownian coagulation were evaluated for various cases. Some of these results were compared with the experimental results obtained by a visual method, and were found to be in good agreement with them.
TL;DR: In this article, the permeation rate and transfer mechanism of copper(II) through a supported liquid membrane containing LIX65N as a mobile carrier were studied under the condition that the rate-determining step of the dialysis was the diffusion in the membrane.
Abstract: Permeation rate and transfer mechanism of copper(II) through a supported liquid membrane containing LIX65N as a mobile carrier were studied. The experiment was carried out under the condition that the rate-determining step of the dialysis was the diffusion in the membrane. The binary diffusivities of the oxime and the copper-oxime complex for solute-solvent system and apparent diffusivity of copper in the supported liquid membrane were measured. The apparent diffusivity of copper was approximately proportional to the -1.0 power of the liquid membrane solution viscosity. The copper flux was constant in the range of pH>3 in the feed solution, but decreased with decreasing pH in the range of pH<3. Copper concentration in the feed solution hardly influenced the copper flux in the range of 10-3-10-1 mol-dm-3. The copper flux was proportional to the 1st power of the oxime concentration in the liquid membrane when pH of the feed solution was 4.47, but the value of the power of the oxime concentration increased with decreasing value of pH of the feed solution. The concentration profile of the copper-oxime complex in a stack of the supported liquid membrane was approximately in agreement with the theory.
TL;DR: In this paper, a new approximate description of adsorption equilibrium of wastewater containing a number of unknown pollutants has been developed by using such a comprehensive index of concentration as TOC, BOD or COD.
Abstract: A new approximate description of adsorption equilibrium of wastewater containing a number of unknown pollutants has been developed by using such a comprehensive index of concentration as TOC, BOD or COD. The description has been constructed on the basis of a new concept, "Characteristic Distribution of Langmuir Coefficient", which is to be identified by the observed differential adsorption equilibrium data. The accuracy of prediction of the integral adsorption equilibrium using this description has been demonstrated by several experiments.
TL;DR: In this article, the extraction of copper was carried out in a stirred transfer cell, using liquid surfactant membranes containing benzoylacetone as a mobile carrier, and the experimental results could be explained by a diffusion model accompanied by chelating complex formation in the aqueous phase close to the external interface of the membranes.
Abstract: A novel separation technique using liquid surfactant membranes containing a mobile carrier has recently attracted practical interest from the point of view of recycling of industrial resources or energy conservation. In this work, the extraction of copper was carried out in a stirred transfer cell, using liquid surfactant membranes containing benzoylacetone as a mobile carrier. At the early stage of copper extraction, it was found that the effects of mass transfer in the liquid membranes and the stripping reaction within water droplets on the overall extraction rate of copper could be neglected, and that copper ion was completely accepted into the water droplets in the emulsion phase. The experimental results could be explained by a diffusion model accompanied by chelating complex formation in the aqueous phase close to the external interface of the membranes. The rate constant of the chelating complex formation and the mass transfer coefficient in the aqueous phase were obtained.
TL;DR: In this article, the effect of migration on the limiting current was analyzed by use of the numerical method for two cases, the transient current at a cylindrical electrode and the steady current at rotating disk electrode.
Abstract: The effect of migration on the limiting current was analyzed by use of the numerical method. The analysis was conducted for two cases, the transient current at a cylindrical electrode and the steady current at a rotating disk electrode. The result of the present analysis for the rotating disk electrode was compared with the approximate analysis of Gordon et al., where the former showed a greater migration effect than the latter. The diffusivities of ferricyanide and ferrocyanide ions in dilute solution with KOH supporting electrolyte were measured by both the unsteady-state and the steady-state methods at 30°C. The concentrations of Fe(CN)63- and Fe(CN)64- were 0.02 to 0.2 kmol/m3, and that of KOH was constant at 1.0 kmol/m3. The diffusivities obtained from both methods coincided well with each other, and also with the available results by many other investigators for equimolar ferricyanide and ferrocyanide ion solutions.
TL;DR: In this paper, the temperature distribution of fluid in an agitated tank equipped with a helical ribbon impeller is visualized by means of liquid crystal particles and the relation between temperature distribution and circulation flow is observed.
Abstract: Temperature distributions of fluid in an agitated tank equipped with a helical ribbon impeller are visualized by means of liquid crystal particles and the relation between temperature distribution and circulation flow is observed. It is concluded that non-uniformities in temperature in an agitated tank should not be neglected in the laminar flow region and that, in this case, a flow model realistic enough to represent the actual flow behavior is necessary. A flow model is developed and applied in order to analyze the steady-state heat transfer system. The introduction of this flow model has been found very effective in expressing the thermal mixing process in an agitated tank with a helical ribbon impeller.
TL;DR: In this article, a hydrogenation reactor with palladium as a catalytic membrane permeated by hydrogen was designed and the mechanism of the hydrogenation of ethylene was analyzed, where the resistance of mass transfer in the gas film can be neglected.
Abstract: A hydrogenation reactor with palladium as a catalytic membrane permeated by hydrogen was designed and the mechanism of the hydrogenation of ethylene was analyzed. It was demonstrated by experiment that, where the resistance of mass transfer in the gas film can be neglected, the range of ethylene partial pressure was distinctly separated into two domains: one domain where the overall reaction rate is approximately proportional to the ethylene partial pressure and another where the overall rate is equal to the permeation rate of hydrogen into vacuum at constant hydrogen pressure. The analysis demonstrated that the two domains correspond to the chemical reaction limitation and the limitation of hydrogen diffusion through the membrane, respectively. It was also demonstrated that the distinct separation of the domains is due to the large value of k0/ki, , which is the ratio of the rate constants of hydrogen dissolution into and out of the palladium membrane. In addition, it was demonstrated that the permeatation rate is scarcely affected by a change in reaction rate under a certain condition. This was in good agreement with the experimental results.
TL;DR: In this article, the side-outlet spouted bed with inner draft-tube has the following advantageous characteristics stemming from the fact that simple rules hold at the beginning of spouting: stable spouting begins when the gas velocity in the inner draft tube increases and the ratio to terminal velocity of solid particles rises to a certain value.
Abstract: It has been found that the side-outlet spouted bed with inner draft-tube has the following advantageous characteristics stemming from the fact that simple rules hold at the beginning of spouting. When the gas velocity in the inner draft-tube increases and the ratio to terminal velocity of solid particles rises to a certain value, stable spouting begins. At the beginning of spouting the ratio of gas velocity in the gas inlet to terminal velocity of solid particles is also constant. These ratios do not change even if the size of the apparatus or the size of particles changes, as far as we have investigated on geometrically similar spouted beds. In addition, the gas streamlines are aproximately similar for geometrically similar spouted beds. These characteristics of the side-outlet spouted bed with inner draft-tube facilitate the procedure for scale-up. For example, the minimum gas flow rate required for stable spouting can be easily predicted and the gas conversion can be easily estimated.