Showing papers in "Journal of Chemical Engineering of Japan in 1976"
TL;DR: In this article, a flow pattern diagram for gas-liquid concurrent downflow in glass beds and in cylindrical and spherical Co/Mo/AI2O3 catalyst packings with foaming and nonfoaming liquids is presented.
Abstract: Flow patterns, pressure loss and liquid holdup for gas-liquid concurrent downflow have been studied in glass beds and in cylindrical and spherical Co/Mo/AI2O3 catalyst packings with foaming and nonfoaming liquids. The different flow patterns encountered in this study are gathered in a flow pattern diagram. Correlations of pressure loss and liquid holdup are proposed in terms of the single-phase friction loss or frictional energy for the liquid and the gas when each flows alone in the bed. The types of correlation depend on the tendency of the fluid to foam or not. A comparison of the flow diagram and the pressure drop and holdup correlation of this work with those of other published studies is also presented.
115 citations
TL;DR: In this paper, phase equilibria were studied in the systems methanol-methyl ethyl ketone, ethanol-methyl ketone and methyl acetate-1-propanol under isothermal conditions.
Abstract: Phase equilibria were studied in the systems methanol-methyl ethyl ketone, ethanol-methyl ethyl ketone, methyl ethyl ketone-2-propanol, methyl acetate-1-propanol, and methyl acetate-2-propanol under isothermal conditions. Heat of mixing data were obtained for these systems. The Wilson and NRTL equations were able to represent simultaneously these two kinds of thermodynamic quantities under the assumption that their parameters were temperature-dependent.
57 citations
TL;DR: In this paper, the mass transfer coefficient kls was measured over a range of flow rates of gas Ug = 0-100 cm and liquid Ul = 0.05-25 cm in a column packed with spheres of three different diameters.
Abstract: Mass transfer coefficient kls was measured over a range of flow rates of gas Ug= 0-100 cm.s-1 and liquid Ul=0.05-25 cm.s-1 in a column packed with spheres of three different diameters d=2.8-12.7 mm. The systems used were the dissolution of benzoic acid in water and diffusionlimited oxidation of brass with dichromate ion in sulfuric acid solution. The effect of Ug on kls is not found at all in gas continuous flow, is the greatest in pulse flow and becomes less significant again in dispersed bubble flow. The value of kls increases rapidly around the transition from gas continuous to pulse flow. The enhancement factor β (=kls in two-phase flow/kls in single-phase flow) increases from 1.2 to 2 with increasing d in gas continuous flow while it equals the reciprocal of liquid holdup in pulse and dispersed bubble flows. A liquid-film analogy in gas continuous flow and a single-phase analogy in pulse and dispersed bubble flows are proposed and the experimental results are examined in the light of them.
54 citations
TL;DR: In this article, two types of stepwise change in the flow rate of a fully developed pipe flow showed apparently different behaviours in this turbulence, and the dominant feature was the generation and propagation of a new turbulence.
Abstract: The dynamic structure of turbulence in transient pipe flows was studied experimentally. Two types of stepwise change in the flow rate of a fully developed pipe flow showed apparently different behaviours in this turbulence. With a stepwise increase in the flow rate, the dominant feature was the generation and propagation of a new turbulence. With a stepwise decrease in the flow rate the dominant feature was the decay of an old turbulence. However, a comparison of these two types of stepwise change indicates a coherent structure in the propagation of a new turbulence in both transient pipe flows. The propagation time of new turbulence is determined by the condition at its generation. Moreover, this coherent character is also applicable to the propagation of an old turbulence, and the beginning of the decay of the old turbulence is predicted by the propagation time in initial steady state. On the basis of these facts the dynamic behaviours of turbulence in both these types of transient flow are interpreted consistently. For the decay of the old turbulence, the ''linear'' decay law is applicable and the decay rate is governed by the flow condition during decay, although the propagation time is not affected by the transient flow.
51 citations
TL;DR: The rate of chemical-initiated bulk polymerization is studied theoretically and experimentally over the complete course of reaction taking into consideration the effects of the decrease of jump frequency of a polymer segment during polymerization on the rate of each elementary reaction.
Abstract: The rate of chemical-initiated bulk polymerization is studied theoretically and experimentally over the complete course of reaction Taking into consideration the effects of the decrease of jump frequency of a polymer segment during polymerization on the rate of each elementary reaction, a new kinetic model is proposed This model is applied to the bulk polymerization of methyl methacrylate and styrene for several initiator concentrations and temperatures Though the polymerization of these monomers shows very different auto-acceleration effects, experimental data of conversion and number-average and weight-average chain length can be successfully correlated to limiting conversion by this model
50 citations
TL;DR: In this paper, an analytical solution of groups model was used to predict infinite dilution binary activity coefficients and isobaric vapor-liquid equilibria for 32 binary and 8 ternary systems involving alcohols, water, paraffins, ketones.
Abstract: Infinite dilution binary activity coefficients have been measured for 6 systems at 40 to 100°C by using an ebulliometer, to develop an accurate and rapid method for determining the group Wilson parameters for predicting liquid phase activity coefficients by "Analytical Solutions of Groups" model. The systems measured are methanol-n-heptane, ethanol-n-heptane, n-butanolwater, acetone-n-heptane, acetone-methanol, methyl ethyl ketone-water. The group Wilson parameters for any system made up of CH2, OH, CO groups have been determined at 40 to 100°C. Predictions of infinite dilution activity coefficients and isobaric vapor-liquid equilibria made for 32 binary and 8 ternary systems involving alcohols, water, paraffins, ketones showed good agreement with observed values.
46 citations
TL;DR: In this article, a characteristic equation for the growth rate of disturbances is theoretically derived on the assumption that disturbances in the liquid are symmetric about the jet axis and those in the surrounding air are non-symmetric.
Abstract: Aerodynamic effects on the breakup of liquid jets in the air flow normal to the jet axis have been studied. A characteristic equation for the growth rate of disturbances is theoretically derived on the assumption that disturbances in the liquid are symmetric about the jet axis and those in the surrounding air are non-symmetric. The numerical analysis of the equation predicts that the maximum growth rate increases with the Weber number based on the density of air. The breakup length was measured by the ejection of water, ethanol and aqueous glycerol solution from a nozzle, whose axis was normal to the direction of air flow. The experimental breakup length agrees with the theoretical one in the region of air velocities less than 500 cm/sec, where the disintegration of jets by symmetric disturbances is observed and the assumption of the jet normal to the air flow appears reasonable.
42 citations
TL;DR: In this article, the authors considered that electrophoresis occurs in the slurry and causes less cake formation, and that electroosmosis occurs at the same time in the filter cake.
Abstract: Filtration under constant D. C. electric field with constant hydraulic pressure, what is termed electrokinetic filtration, was discussed in this paper. Under these conditions it is considered that electrophoresis occurs in the slurry and causes less cake formation, and that electroosmosis occurs at the same time in the filter cake. Therefore, the flow rate of electrokinetic filtration is increased in comparison to filtration at the same hydraulic pressure. An equation taking account of both effects is presented. Experimental investigation of the characteristics of electrokinetic filtration is performed according to the theoretical equation. As a result, the flow rate of filtration is significantly increased for calcium carbonate slurry and white clay slurry. For instance, at the electric field of 30 volt/cm under hydraulic pressure of 163.2 G/cm2, Ruth''s filtration coefficient for calcium carbonate slurry was about 9.4 times as large as that of the filtration at the same hydraulic pressure, and Ruth''s coefficient for white clay slurry was about 15 times at 12volt/cm and 163.2 G/cm2. It is confirmed that the equation of electrokinetic filtration proposed in this paper is practically available.
40 citations
TL;DR: In this article, the mechanism of electroosmotic dewatering of compressible sludge under condition of constant electric current was discussed, based on the model of electro-sotic flow through the particle packed bed.
Abstract: It is possible to apply electroosmosis to dewatering of sludge In this paper, the mechanism of electroosmotic dewatering of compressible sludge under condition of constant electric current was discussed, based on the model of electroosmotic flow through the particle packed bed, and the effects of the operating conditions on the rate of electroosmotic dewatering and the electric power consumption were theoretically analysed The equations obtained theoretically were confirmed experimentally under condition of constant electric current with the compressible sludges such as white clay, magnesium hydroxide and bentonite Theoretical equations were available for the design of electroosmotic dewatering apparatus The electroosmotic dewatering was particularly effective for gelatinous sludges
35 citations
35 citations
TL;DR: In this paper, the axial dispersion in the liquid-phase of a gas-liquid downflow through a packed column was studied with air and water flowing concurrently in a 8.0 cm diameter column with glass spheres of 0.12, 0.26 and 0.43 cm.
Abstract: The axial dispersion in the liquid-phase of a gas-liquid downflow through a packed column was studied with air and water flowing concurrently in a 8.0 cm diameter column with glass spheres of 0.12, 0.26 and 0.43 cm. The impulse response was calculated numerically from the two signals measured at two cross-sections in the bed. The response was characterized by both a peak and a very long tail, and could be represented satisfactorily by using the PDE model in which the mass transfer between the dynamic and the stagnant holdups in addition to the axial dispersion in the dynamic holdup was taken into account. Four parameters appearing in the PDE model were determined by means of the time domain curve fitting method. Peclet number which was based on the actual velocity in the dynamic holdup ud had a constant value of 0.43 for Re''(=udρdp/μ) 400. The volumetric mass transfer coefficient was correlated as a function of particle size, liquid and gas velocities. The total liquid holdup agreed well with the literature data. The fraction of the dynamic holdup varied in the range of 0.6 to 0.95 depending on the particle size and the gas and the liquid velocities. The correlation of the dynamic liquid holdup was given graphically.
TL;DR: In this article, an improved and simplified method to design fixed-bed adsorbers is developed under the assumption of a constant pattern of concentration distribution for the Freundlich isotherm systems.
Abstract: An improved and simplified method to design fixed-bed adsorbers is developed under the assumption of a constant pattern of concentration distribution for the Freundlich isotherm systems. The intraparticle mass transfer rate is approximated by a modified linear-driving-force expression. The diagrams showing three parameters, which are necessary to estimate the break time, are presented and the procedures for predicting the break time and the breakthrough curve are presented.
TL;DR: In this paper, the relative humidity of saturated aqueous solutions of inorganic salts has been widely used in a laboratory and the results appearing in the literature differ up to several percentages.
Abstract: In order to control the relative humidity of air, saturated aqueous solutions of inorganic salts have been widely used in a laboratory. There are several methods available for determining the value of the relative humidity over the saturated salt solution. In many cases the vapor pressure of water in equilibrium with the solution is measured and then the ratio p/ps is calculated. A large number of experimental results based on this method have been reported. The results appearing in the literature2)5)6), however, differ up to several percentages. It may be considered that the disagreement have been due to the following: 1) Vapor pressures are usually measured in an
TL;DR: In this paper, the effect of liquid flow rate, gas flow rate and nozzle to vessel diameter ratio on the spouting of gas bubbles in a gas-liquid spouted vessel was studied experimentally.
Abstract: In a gas-liquid spouted vessel, where power is supplied from a pump to water and gas is introduced at a nozzle attached at the bottom of the vessel, gas bubbles are finely broken at the nozzle and dispersed to the vessel. Gas hold-up in the gas-liquid spouted vessel rapidly increases with increasing liquid flow rate and easily exceeds twice the gas hold-up in the aerated tower of the same gas flow rate with no liquid flow, though co-current liquid flow gives zero or negative effect on gas hold-up in the aerated tower. Effect of liquid flow rate, gas flow rate, nozzle to vessel diameter ratio and nozzle length one ffective spouting of gas bubbles were studied experimentally. Ways are also considered to scale up the gas-liquid spouted vessel.
TL;DR: In this article, a 0.5 % Pt-Al2O3 cylindrical pellet was used for liquid-phase hydrogenation of styrene in a stirred basket reactor.
Abstract: The reaction characteristics of a catalyst pellet is examined in the liquid-phase hydrogenation of styrene in a stirred basket reactor. The catalyst used is a 0.5 % Pt-Al2O3 cylindrical pellet. The intrinsic kinetic expression of the Langmuir-Hinshelwood form is fashioned from the rate measurements in a stirred slurry reactor in which the finely crushed pellets are suspended. With the catalyst pellets the pore diffusion of hydrogen is observed to be significant. The effectiveness factor of the catalyst pellet is computed on the basis of a simplified theoretical model. The connection between the catalytic effectiveness factors obtained experimentally and theoretically makes it possible to estimate the effective diffusivity of hydrogen and the tortuosity factor of the catalyst pellet. The tortuosities ranging from 2.5 to 3.2, secured at the three temperature levels, are shown to be reasonable values for the pore diffusion within a liquid filled catalyst.
TL;DR: In this article, an investigation of heat transfer to a flow of air in an annulus under an electric field applied between the wall of a tube and a concentric wire electrode is presented.
Abstract: This paper presents the results of an investigation of heat transfer to a flow of air in an annulus under an electric field applied between the wall of a tube and a concentric wire electrode. By electrically induced disturbance, the heat transfer rate in the low Reynolds number region is increased, being accompanied by the augmentation of axial pressure drop. At high Reynolds number, however, this augmentation is not noticiable. Augmented heat transfer and pressure drop coefficients were correlated in non-dimensional terms derived from the similarity principle and analytical cinsideration of the predominant electric effect. Moreover, semiempirical formulations of these augmenting mechanisms were attempted by analyzing the measured temperature profiles and flow behaviour.
TL;DR: In this paper, the velocity of thermophoresis of aerosol particles in the slip flow region was studied from the experimental point of view, and the experimental results were compared with some of the most representative theories, and were found in good agreement with Derjaguin's theory.
Abstract: The velocity of thermophoresis of aerosol particles in the slip flow region, about which no conclusion has yet been drawn from the many results of experimental and theoretical work, was studied from the experimental point of view. A new experimental method using an ultramicroscope was developed to meet most of the necessary conditions to obtain reliable data on thermophoresis, such as accurate observation of velocity under an accurately known temperature gradient and prevention of the action of any forces except thermal force. The experimental results were compared with some of the most representative theories, and were found in good agreement with Derjaguin''s theory.
TL;DR: In this paper, the performance of a cocurrent up-flow this paper with glass beads was studied using the oxidation reaction of sodium sulfite, at a reaction temperature of 20°C.
Abstract: Packed-bed cocurrent up-flow reactors gave better results than conventional trickling flow reactors in hydrodesulfurization of heavy oil. To find the characteristics of this up-flow type reactor, liquid-phase mass transfer coefficient, gas-liquid interfacial area and gas holdup in a column packed with 0.1, 0.28 or 0.43 cm glass beads were studied using the oxidation reaction of sodium sulfite. Experiments were carried out at a reaction temperature of 20°C. Superficial liquid and gas velocities based on empty column, ul and ug, were 1-6 and 0.5-6cm/sec, respectively, for any size of glass beads. With the values of ul and ug, glass beads bed remained stationary, expanded or fluidized. Stagnant gas holdup was observed under the condition of ul
TL;DR: In this article, a general method for mathematical simulation of multicomponent equilibrium stage processes is presented, which consists of solving component material balance equations with a tridiagonal matrix algorithm and performing equilibrium calculation based on the "pseudoequilibrium" concept, instead of solving simultaneous equilibrium equations by some optimization method.
Abstract: A new general method for mathematical simulation of multicomponent equilibrium stage processes is presented. The procedure consists of solving component material balance equations with a tridiagonal matrix algorithm and performing equilibrium calculation based on the "pseudoequilibrium" concept, instead of solving simultaneous equilibrium equations by some optimization method. The present method is simple, fast and numerically stable. The application of the method to multistage, multicomponent extraction problems is described. Moreover, the feasibility of the modified Wilson equation to extraction problems is shown.
TL;DR: In this paper, a correlation for the volumetric mass transfer coefficient was developed semi-empirically based on the analogy between mass and momentum transfer in vertical upward two-phase flow by desorbing carbon dioxide from liquid phases of water, aqueous glycerine and malt honey.
Abstract: Liquid-side volumetric mass transfer coefficients were obtained in vertical upward two-phase flow by desorbing carbon dioxide from liquid phases of water, aqueous glycerine and malt honey. Measurements were made mainly in the froth and the wavy annular flow using tubes of 10, 18 and 25 mm i.d. A correlation for the volumetric mass transfer coefficient was developed semi-empirically based on the analogy between mass and momentum transfer. Experimental data were correlated by two equations in dimensionless form corresponding to the two flow mechanisms of pseudo-laminar flow and turbulent flow.
TL;DR: In this paper, an ellipsoid bouncing model was extended to simulate gas-solid suspension flow in a circular pipe and compared with experiments in terms of concentration distribution, particle velocity, additional pressure drop and frequency of particle collisions with the pipe wall.
Abstract: An ellipsoid bouncing model, previously presented to express the irregular bounce of particles on a duct wall, was extended to simulation of gas-solid suspension flow in a circular pipe. Simulated results were compared with experiments in terms of concentration distribution, particle velocity, additional pressure drop and frequency of particle collisions with the pipe wall. If the mean observed deformation, ηob, was taken as the value of the parameter, the mechanism of particle motion was explained for the most part by the simulation.
TL;DR: In this paper, the surface diffusion coefficient on each carbon was determined for each system by applying the concentration diagrams previously presented by the authors, and it was shown that surface diffusion decreased in proportion to the square root of the molecular weight of the polymer.
Abstract: Adsorption of poly(oxyethylene) of nine different molecular weights ranging from 194 to 2.49×106 from aqueous solution of 100 mg/l on activated carbons was tried in a batch finite bath. Activated carbon of coconut shell base, which has micropores of 8 A radius, and of lignite base activated carbon showed a reasonable capacity of adsorption of even poly(oxyethylene) of molecular weight bigger than 104 which has Flory''s dimension of 84 A radius. This suggests that shrinkage of a polymer molecule occurs when it is adsorbed on the carbon surface. As for the rate of adsorption, surface diffusion possibly caused by migration of monomer units is considered dominant, and the effective surface diffusion coefficient was determined for each system by applying the concentration diagrams previously presented by the authors. The effective surface diffusion coefficient on each carbon decreased in proportion to the square root of molecular weight of the polymer.
TL;DR: In this paper, the effect of the gas and liquid flow rates on the mass transfer rate in laminar gas streams in wetted-wall columns with cocurrent gas-liquid flow was studied.
Abstract: The effect of the gas and liquid flow rates on the mass transfer rate in laminar gas streams in wetted-wall columns with cocurrent gas-liquid flow was studied. An analytical solution was obtained for the average gas-phase Sherwood number as a function of the gas-phase Graetz number and the dimensionless interfacial gas velocity. Experiments were carried out on the absorption of ammonia into sulfuric acid solution and of methanol vapor into water, using three columns of different dimensions. The agreement between the experimental and the predicted effects of both gas and liquid flow rates on the gas-phase mass transfer rate was found to be fairly good.
TL;DR: In this article, a homogeneous nucleation rate equation (1) was derived theoretically, which is in the same form as that often applied in engineering treatment, and the nucleation parameters (m and radius and specific surface energy of a critical nucleus) obtained on the basis of Eq. 1 were of reasonable order of magnitude and were in fair agreement with those obtained by Preckshot''s method.
Abstract: A homogeneous nucleation rate equation (1) was derived theoretically, which is in the same form as that often applied in engineering treatment. J=k1Sm (1)where S is supersaturated ratio, m is the number of solutes in a critical nucleus, and it is not constant, but depends on S and temperature. In order to examine the validity of Eq. (1), the nucleation of KC1O3 from its supersaturated aqueous solution was carried out. The nucleation rate was measured in terms of the waiting time, by using a differential scanning calorimeter. The values of the nucleation parameters (m and radius and specific surface energy of a critical nucleus) obtained on the basis of Eq. (1) were of reasonable order of magnitude and were in fair agreement with those obtained by Preckshot''s method. As a result, it was concluded that Eq. (1) is adequate for the homogeneous nucleation rate.
TL;DR: The applicability of the extended Kretschmer-Wiebe equation was examined by taking account of both the self-association of methanol and the association of unlike molecules between methanols and polar solvents as discussed by the authors.
Abstract: Liquid-liquid equilibria for the three systems methanol-ethyl ether-cyclohexane, methanoltetrahydrofuran-cyclohexane, and methanol-methyl acetate-cyclohexane were measured at 25°C For these systems, the applicability of the extended Kretschmer-Wiebe equation was examined by taking account of both the self-association of methanol and the association of unlike molecules between methanol and polar solvents For methanol ethyl ether cyclohexane system, experimental data gave reasonable agreement with the binodal curve calculated by use of the parameters obtained from binary data alone For the other two systems, the agreement between experimental and calculated binodal curves were not satisfactory The NRTL equation was also utilized to calculate the ternary liquid-liquid equilibria from the constituent binary data, but it failed to represent the experimental solubility data