Showing papers in "Journal of Chemical Engineering of Japan in 1984"
TL;DR: In this paper, a simple model which takes into account both adsorption properties and apparatus characteristics was proposed to interpret the experimental results quantitatively, and the transitional behavior of heat and mass transfer in continuous adsorbption-regeneration experiments was successfully interpreted by the model.
Abstract: Fundamental experiments on the solar-powered adsorption cooling system were carried out with small-scale apparatus simulating ideally a practical unit by employing a combination of silica-gel and water vapor as an example of the adsorbent-adsorbate combinations. A simple model which takes into account both adsorption properties and apparatus characteristics was proposed to interpret our experimental results quantitatively. Then the transitional behavior of heat and mass transfer in continuous adsorption-regeneration experiments was successfully interpreted by the model. The model proposed here is not a complete one and is to be considered as a first-step model for estimating operation with practical equipment. Also, the contribution of the level of regeneration temperature of adsorbents to the cooling performance was quantitatively clarified on the basis of the adsorption equilibrium relation, which is considered useful in choosing a favorable combination of adsorbent and adsorbate for the system.
281 citations
TL;DR: In this article, an ad-sorption isotherm for a heterogeneous surface is described on the basis of a multi-site occupancy model followed by a group-contribution assumption.
Abstract: An adsorption isotherm for a heterogeneous surface is described on the basis of a multi-site occupancy model followed by a group-contribution assumption. Equations of single- and multi-component adsorptions are derived for systems of molecules consisting of several functional groups and a surface composed of active sites of different energies interacting with the groups independently. The isotherm equation reduces to the expression derived by Sparnaay in the special case where a molecule occupies one site of the surface. The theory is applied to adsorption equilibria for systems of oxygen, nitrogen, and carbon monoxide on Molecular Sieves 5A and 10X. Correlations of single-component isotherms are excellent for nitrogen and oxygen and fairly good for carbon monoxide; predictions of adsorption isotherms of binary gas mixtures are made satisfactorily by means of parameters determined from the best fit to each single-component isotherm.
226 citations
TL;DR: In this article, the authors investigated flow characteristics in a channel with a symmetric wavy wall and showed that the variation of pressure drop and wall shear stress with the Reynolds number was elucidated by the behavior of the circulated vortex formed at the diverging cross section of the channel.
Abstract: Flow characteristics in a channel with a symmetric wavy wall were investigated by calculations and experiments. The channel used has a geometry similar to that of the Oxford membrane blood oxygenator. The flow regime covered ranged from laminar to turbulent flow. The variation of pressure drop and wall shear stress with the Reynolds number was elucidated by the behavior of the circulated vortex formed at the diverging cross section of the channel.
176 citations
TL;DR: In this paper, three new hydrating agents, R13 (CC1F3), R23 (CHF3) and R152a (C2H4F2), and propane were selected.
Abstract: The objective of this investigation was to obtain basic data which are necessary to develop a new hydrate process for desalination of sea water. Three new hydrating agents, R13 (CC1F3), R23 (CHF3) and R152a (C2H4F2), and propane were selected. The pressure-temperature phase diagrams of each agent for pure water and aqueous NaCl solution were determined in the temperature range from 260 to 295 K and pressures up to 4.4 MPa. Based on the pressure-temperature data obtained, the necessary thermodynamic data, such as hydrate decomposition conditions, invariant points, heat of formation, and hydrate composition were determined.
138 citations
TL;DR: In this paper, the effects of column dimensions, gas velocity and the properties of liquid and solid particles on the gas holdup eG and the volumetric liquid-phase mass transfer coefficient kLa in the solid-suspended bubble column of liquid-solid batch operation were studied experimentally.
Abstract: The effects of column dimensions, gas velocity and the properties of liquid and solid particles on the gas holdup eG and the volumetric liquid-phase mass transfer coefficient kLa in the solid-suspended bubble column of liquid-solid batch operation were studied experimentally. The presence of suspended solid particles in the bubble column reduces values of eG and kLa, and their reduction by an addition of solid particles to the column is high in the transition regime and low in the heterogeneous flow regime. Based on these observations, empirical equations for eG in transition flow and in heterogeneous flow, and an empirical equation for kLa a applicable to the above two flow regimes are proposed.
117 citations
TL;DR: In this article, a method of preparing anodic aluminum oxide membranes is presented, which consists of close-packed cells of oxide, hexagonal in shape, each of which contains a single pore formed perpendicularly to the surface of the aluminum substrate.
Abstract: The details of a method of preparing anodic aluminum oxide membranes are presented. The porous oxide layer consists of close-packed cells of oxide, hexagonal in shape, each of which contains a single pore formed perpendicularly to the surface of the aluminum substrate. This special structural feature is essentially important for ultrafiltration and gas separation. The rejection characteristics are examined, using aqueous and nonaqueous solutions of macromolecules. The permeability of gases is also examined at different temperatures. The flow of gases is explained by the Knudsen regime alone.
112 citations
TL;DR: In this article, the effects of gas velocity and geometrical dimensions of apparatus on the flow rate of circulating liquid, gas holdups and pressure drops in bubble columns with draught tube were examined.
Abstract: The effects of gas velocity and geometrical dimensions of apparatus on the flow rate QL of circulating liquid, gas holdups and pressure drops in bubble columns with draught tube were examined. It was found that QL increases with increasing gas velocity, column diameter, draught tube length, and height of the lower end of draught tube, and decreases with increasing liquid viscosity. It was also found that the maximum value of QL is observed for constant values of gas velocity and column diameter, when the diameter ratio of draught tube and column is about 0.6. Empirical equations for gas holdups in draught tube and annulus and the pressure drops due to flow reversals, necessary for estimating QL, are proposed.
55 citations
TL;DR: In this article, the mechanism of scale formation on reverse-osmosis membranes was studied by the introduction of a theory of crystallization, and the results showed that the growth rate constant and waiting period before nucleation obtained in long-term runs were reasonable in comparison with data obtained from the literature cited.
Abstract: The mechanism of calcium sulfate dihydrate scale formation on reverse-osmosis membranes was studied by the introduction of a theory of crystallization. According to this theory, the values of the growth rate constant and the waiting period before nucleation obtained in long-term runs were reasonable in comparison with data obtained from the literature cited. From these experimental results, the theory proved to be applicable to scale formation on reverse-osmosis membranes. For practical application, the theory could be extended to binary system solutions containing sodium chloride, which is the major component in sea and brackish water, with adequate approximations. Using this theory, we can predict membrane characteristics during scale formation.
53 citations
TL;DR: In this paper, the critical gas velocity required for complete suspension of solid particles was studied experimentally in a solid-suspended bubble column with a draught tube, and an empirical equation for critical gas velocities was proposed that is applicable to columns with diameters of 1-03 m.
Abstract: The critical gas velocity required for complete suspension of solid particles was studied experimentally in a solid-suspended bubble column with a draught tube It was shown that the critical gas velocity increases with increasing terminal velocity of a single particle, solid concentration, liquid surface tension, diameter of gas distributor and density difference between solid and liquid, and decreases with increasing column diameter and liquid viscosity Based on these observations, an empirical equation for critical gas velocity is proposed that is applicable to columns with diameters of 01-03 m
50 citations
TL;DR: In this article, the effect of diluent in the extraction of Co, Ni and Na from nitrate media with di(2-ethylhexyl)phosphoric acid (HDEHP) and 2-hexylphosphonic acid mono-2-methylhexyl ester (EHPNA) was studied, using nonpolar hydrocarbons and polar solvents with different electron-donor strength as diluents.
Abstract: The effect of the diluent in the extraction of Co, Ni and Na from nitrate media with di(2-ethylhexyl)phosphoric acid (HDEHP) and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (EHPNA) was studied, using non-polar hydrocarbons and polar solvents with different electron-donor strength as diluents. The effect caused by the diluent-extractant interaction was found to be relatively weak, owing to the great tendency toward self-association of the extractant. With the higher alcohols as diluent, however, the diluent can coordinate with the extracted metal complex in the Co/HDEHPsystem. Furthermore, it substitutes for the neutral extractant molecule in the nickel complex. This substitution and the stabilization of the associated water molecules by the alcohol diluent enhances nickel extraction, achieving the same performance as in cobalt extraction. Successively larger aggregated metal complexes appear in all diluents tested, to differing extent depending on the nature of the diluent. Equilibrium formulations were determined for various combinations of metal and diluent.
48 citations
TL;DR: In this paper, the axial dispersion coefficients of liquid were measured for liquid fluidized beds in the low Reynolds number region by the residence-time-curve method, and the experimental results were successfully correlated by the following empirical equation: Ez/v= 500e0.43 exp {- 20.5(0.75 - e)2} 0.410-5
Abstract: Axial dispersion coefficients of liquid were measured for liquid fluidized beds in the low Reynolds number region by the residence-time-curve method. Particles used were polystyrene and glass beads of diameter from 239 to 1887 μm. The experimental results were successfully correlated by the following empirical equation: Ez/v= 500e0.43 exp {- 20.5(0.75 - e)2} 0.410-5where Ez is the axial dispersion coefficient, e the kinematic viscosity of liquid, s the energy dissipation rate [m2/s3], e the void fraction and Re0 the particle Reynolds number based on superficial velocity. Most of the published correlations estimate too large values of the axial dispersion coefficient over the low Reynolds number region except in the case of glass beads of small diameter.
TL;DR: In this paper, the authors investigated the kinetics of reaction of carbon monoxide and carbon dioxide with hydrogen in a nickel catalyst tube wall reactor and the reaction mechanisms were clarified theoretically from the proposed reaction mechanism.
Abstract: The kinetics of reaction of carbon monoxide and carbon dioxide with hydrogen in a nickel catalyst tube wall reactor were investigated experimentally and the reaction mechanisms were clarified. The observed rate laws were -rco = (k1PH2P1/2CO)/(1 + KCOPCO) for carbon monoxide, and -rco2 = (k''PH2P1/3CO2)/(1 + KCO2PCO2 + KH2 + KH2OPH2O)for carbon dioxide at low partial pressure. These reaction rate laws were derived theoretically from the proposed reaction mechanism. For a mixture of carbon monoxide and carbon dioxide the kinetics of the reaction proved to be well accounted for by the same reaction mechanism.
TL;DR: In this paper, the authors investigated bubble formation with weeping at a submerged orifice over a range of orifice diameters of 3-13.2 mm and obtained empirical relationships predicting each transitional point of bubble formation regimes.
Abstract: Bubble formation phenomena with weeping at a submerged orifice were investigated experimentally over a range of orifice diameters of 3-13.2 mm. There appeared to be four regimes of interest: single bubbling at small chamber volumes and low gas flow rates, doubling noticed with increasing gas flow rate, jetting at further increase of gas flow rate and pairing at very large chamber volumes under conditions of gas flow rates smaller than those for jetting point. Empirical relationships predicting each transitional point of bubble formation regimes are obtained.
TL;DR: In this paper, the authors decrit les resultats experimentaux obtenus avec un lit fluidise horizontal tournant, pour diverses densites de particules and distributions granulometriques, en vue de determiner la vitesse minimale de fluidisation, the perte de charge maximale, the variation de perte of charge avec la vitese de rotation and l'expansion du lit.
Abstract: On decrit les resultats experimentaux obtenus avec un lit fluidise horizontal tournant, pour diverses densites de particules et distributions granulometriques, en vue de determiner la vitesse minimale de fluidisation, la perte de charge maximale, la variation de perte de charge avec la vitesse de rotation et l'expansion du lit
TL;DR: In this article, the rate of demulsification of W/O emulsion was studied experimentally, using a batch A.C. electric demulsifier, and it was shown that the rate is proportional to C-0.5S and increases as CLIX and CE increase.
Abstract: The rate of demulsification of W/O emulsion was studied experimentally, using a batch A.C. electric demulsifier. The oil phase was kerosene, containing Span 80 as a surfactant (Cs = 1-7 wt %), and LIX64N as an extraction reagent (CLIX=0-8wt%). The water phase contained an electrolyte such as NaCl, H2SO4 or CuSO4 (CE = 0-0.6 mol/dm3). It is clarified that the rate of demulsification is proportional to C-0.5S and increases as CLIX and CE increase. An experimental equation is presented for estimation of the demulsification rate.
TL;DR: On et al. as mentioned in this paper propose a relation empirique basee sur la methode de Metzner et Otto, based on the assumption that the consommation d'energies d'agitateurs a ruban de different variables geometriques, en regime laminaire
Abstract: Mesure de la consommation d'energie d'agitateurs a ruban de differentes variables geometriques, en regime laminaire On propose une relation empirique basee sur la methode de Metzner et Otto
TL;DR: In this paper, a useful method composed of two stages-search for the optimal separation sequence, and optimization of the separation process by introduction of division and blending-is developed for synthesis of two multicomponent products.
Abstract: Introduction of division and blending into the separation process of multicomponent products is effective from the viewpoint of reduction of the separation mass load, but it is difficult to solve this synthesis problem because there exists information feedback between the separation sequence and introduction of division and blending. A useful method composed of two stages-search for the optimal separation sequence, and optimization of the separation process by introduction of division and blending-is developed for synthesis of the separation process of two multicomponent products. For the former the evolutionary method, developed for the synthesis of the separation process of pure-substance products, is adopted, and for the latter a new evolutionary method, which uses the material allocation diagram to obtain useful information about the separation process, is developed. A 5-component separation process synthesis problem demonstrates the effectiveness of this method.
TL;DR: In this article, a theoretical treatment for bubble formation with weeping is performed to predict bubble volume in the single bubbling regime where weeping through an orifice occurs after the detachment of a bubble, and a comparison with measurements is made.
Abstract: Bubble volumes in the single bubbling regime, which is one of bubble formation regimes with weeping, are larger than those for bubble formation without weeping. A theoretical treatment for bubble formation with weeping is performed to predict bubble volume in the single bubbling regime where weeping through an orifice occurs after the detachment of a bubble, and a comparison with measurements is made.
TL;DR: In this article, a multi-site occupancy model for homogeneous surface represents the isotherms fairly well, but the calculated amounts of adsorption are usually less than those observed at low surface coverage.
Abstract: Equilibrium data for single-component adsorption on activated fiber carbon, KF-1500 are presented for the five gases methane, ethane, propylene, 1-pentane and carbon dioxide at 0, 25 and 50 °C. An adsorption equation by a multi-site occupancy model for homogeneous surface represents the isotherms fairly well, but the calculated amounts of adsorption are usually less than those observed at low surface coverage. The deviation may be attributed to the surface heterogeneity, which is neglected in the equation. From a comparison of isotherms on glanular and fiber activated carbons, it is suggested that the difference is only in the specific surface area, and that the other two parameters, the number of sites occupied by a molecule and the adsorption equilibrium constant, are almost the same for the two activated carbons.
TL;DR: In this paper, a finite difference method was used for heat and mass transfer of a solid sphere without and with uniform, sinusoidal and evaporative mass injection or suction.
Abstract: Numerical analyses for heat and mass transfer of a solid sphere without and with uniform, sinusoidal and evaporative mass injection or suction were made by use of a finite difference method for Rep = 1-200, Pr or Sc = 0.5-2 and φ= -0.2-0.5. Numerical results for the case without mass injection or suction showed good agreement with the results of previous workers. Heat and mass transfer rates with uniform mass injection or suction were found to be affected by Rep and Pr or Sc as well as mass injection ratio, φ. New correlations for the effect of mass injection or suction on heat and mass transfer rates for the case with uniform and sinusoidal mass injection or suction in terms of transfer number were proposed. Heat and mass transfer rates with sinusoidal mass injection or suction showed good agreement with those for evaporative mass injection or suction.
TL;DR: In this paper, the optimal operating conditions for the separation of cobalt from nickel were determined for a single-stage extraction followed by a single scrubbing process, where non-polar solvents were used as diluents.
Abstract: A practical study was carried out to determine the optimal operating conditions for the separation of cobalt from nickel. With non-polar solvents as diluents, no problem associated with the viscosity of the organic phase and the interfacial tension arises so long as the loading ratio of the organic phase is maintained less than 0.8. A cobalt solution containing a nickel contamination of less than 0.005% was obtained, using single-stage extraction followed by single scrubbing. The addition of 10 % 2-ethylhexyl alcohol results in serious lowering of the separation factor, although it has the advantage of preventing third-phase formation during the conversion of the extractant to its sodium salt. The alkali metal hydroxide equivalent to the amount of metal to be extracted is required in the extraction. As a prospective process, a continuous extraction was carried out satisfactorily in which sodium hydroxide solution was fed into the stage together with the acid form of the extractant diluted in xylene and the aqueous feed stream.
TL;DR: A coaxial cylindrical cell was constructed for measuring thermal conductivities of nine pure fluids (argon, nitrogen, oxygen, helium, carbon dioxide, methane, ethane, ethylene and propane) at temperatures ranging from 25 to 76°C under pressures up to 17.5 MPa as discussed by the authors.
Abstract: A coaxial cylindrical cell was constructed for measuring thermal conductivities of nine pure fluids (argon, nitrogen, oxygen, helium, carbon dioxide, methane, ethane, ethylene and propane) at temperatures ranging from 25 to 76°C under pressures up to 17.5 MPa. Thermal conductivities of two binary mixtures (argon-nitrogen and methane-ethylene) were also measured at 30.6, 50.6 and 76.6 °C under pressures up to 9.8 MPa. The apparatus was calibrated with eight kinds of gases. The Stiel-Thodos and Crooks-Daubert correlations were applied to predict the effect of pressure on the thermal conductivity of pure fluids. They were also extended to the mixtures by use of the van der Waals one-fluid model. Fairly good agreement was obtained with the experimental data as well as those from the literature except in the vicinity of the critical region.
TL;DR: In this article, the Stokes number for a Bingham plastic fluid, Bingham number and the pressure gradient ratio were used to estimate the non-Newtonian flow of a clay slurry in a circular pipe.
Abstract: Laminar pulsating flow of a clay slurry in a circular pipe was studied experimentally. The flow behaviour of the slurry was approximated as that of a Bingham plastic fluid. The addition of sinusoidal pulsating fluctuation to a steady pressure gradient resulted in enhancement of the flow rate, because of the non-Newtonian behaviour of the slurry. The flow enhancement increased with the following conditions: (1) an increase in pulsating amplitude, (2) a decrease in pulsating frequency and (3) a decrease in the mean pressure gradient. The flow enhancement can be expressed as a function of three dimensionless groups: Stokes number for a Bingham plastic fluid, Bingham number and the pressure gradient ratio. An empirical correlation among these dimensionless numbers is presented. All experimental data could be closely correlated with respect to the flow enhancement.
TL;DR: Mesure de la separation d'un melange He-CO 2 cocourant, dans un domaine de temperature 296-947 K, obtenue precedemment par les auteurs as mentioned in this paper.
Abstract: Mesure de la separation d'un melange He-CO 2 a cocourant, dans un domaine de temperature 296-947 K. Analyse theorique au moyen d'une equation de diffusion en fonction de la temperature, obtenue precedemment par les auteurs
TL;DR: In this paper, the authors etudie le melangeage de liquides dans des reservoirs ouverts par un panache de bulles en utilisant la reponse d'un traceur.
Abstract: On etudie le melangeage de liquides dans des reservoirs ouverts par un panache de bulles en utilisant la reponse d'un traceur. On etudie le temps de circulation et le temps de melangeage par comparaison avec ceux d'un melangeur a jet liquide. On determine le meilleur emplacement pour la buse d'arrivee de gaz
TL;DR: In this article, the authors measured liquid phase adsorption equilibria of phenol, p-chlorophenol and p-cresol for macroreticular polymeric adsorbents, Amberlite XAD-4 and XADs, over a wide range of concentration at three temperatures from 273 to 323 K, to find an equation which correlates the equilibrium data best.
Abstract: Liquid-phase adsorption equilibria of phenol, p-chlorophenol and p-cresol for macroreticular polymeric adsorbents, Amberlite XAD-4 and XAD-7, were measured over a wide range of concentration at three temperatures from 273 to 323 K, in order to find an equation which correlates the equilibrium data best. Among the theoretical equations proposed previously in the literature, the equation of Jossens et al. derived thermodynamically on the basis of a heterogeneous surface adsorption theory was proved to be most satisfactory over the entire range of concentration. All conditions assumed in the derivation of the equation were found to be valid. An equation based on the vacancy solution theory gave a fairly good representation. The equations proposed by Okazaki et al. and Toth, respectively, were not applicable to the present cases. The equilibrium data were also correlated by an adsorption potential theory, which enables us to predict the adsorption isotherm at different temperatures.
TL;DR: In this paper, a fluid bed model considering a decrease in number of moles caused by reactions is proposed to analyze the data obtained with a fluid-bed reactor of 8.1cm i.d.
Abstract: Methanation of CO in a fluid bed, carried out by Ni catalyst at 573K and atmospheric pressure, was studied experimentally and theoretically. Reaction rates of methanation and the water-gas shift reaction were measured in a fixed bed reactor. A fluid bed model considering a decrease in number of moles caused by reactions is proposed to analyze the data obtained with a fluid bed reactor of 8.1cm i.d. An effective bubble diameter is introduced as an adjustable parameter in the model. The experimental results are well explained by the model when the bubble diameter is assumed to be 3.6cm. It is found that the influence of the decrease in number of moles on conversion cannot be ignored in analyzing the fluid-bed reaction data.
TL;DR: In this article, a new correlation equation was proposed which correlated all the experimental data very well, taking into account the effect of high mass flux and variable properties, and showed good agreement with the low-flux equation by Ranz and Marshall and also with previous numerical solutions.
Abstract: Experimental studies on the rate of evaporation of a volatile, pendant liquid drop under high ambient temperature conditions (high mass flux) were carried out for the evaporation of water, methanol, n-hexane, n-pentane and carbon tetrachloride drops into dry air. Measurements were made for Rep = 32-328, Sc = 0.60-1.66 and dimensionless driving force B=0.02-1.36. Experimental results for the rate of evaporation of a liquid drop under low ambient temperature conditions showed good agreement with the low-flux equation by Ranz and Marshall and also with previous numerical solutions. Experimental results for rate of evaporation under high ambient temperature conditions showed a systematic deviation from the Ranz-Marshall correlation. Taking into account the effect of high mass flux together with the effect of variable properties, a new correlation equation was proposed which correlated all the experimental data very well.
TL;DR: In this article, the fundamental relations such as equilibrium and intraparticle diffusion in removal of ammonium from wastewaters by natural zeolite are examined by using two different clinoptilolite samples collected from Korea and Japan.
Abstract: The fundamental relations such as equilibrium and intraparticle diffusion in removal of ammonium from wastewaters by natural zeolite are examined by using two different clinoptilolite samples collected from Korea and Japan. The selectivity coefficient of ammonium ion versus sodium ion in these materials defined from mass action law, ?? does not take a constant value as in the case of organic exchange resin, but varies with degree of exchange, YNH4+, in the zeolite. Then it can be correlated as: ?? Also, the intraparticle diffusion coefficient was determined from ion exchange measurement in a stirred tank. The effective diffusion coefficient of the two ions in clinoptilolite was evaluated as 4-5 × 10-12m2/s.
TL;DR: In this paper, a model based on detailed measurement of the relationship between bubble coalescence at the bed surface and particle swarm ejection caused by bubble eruption is proposed, which can be used to predict the passing frequency of swarms in the freeboard, the maximum rise height of the particle swarms, and the entrainment rate below the TDH.
Abstract: A bubble eruption model in which the effect of bubble coalescence near the bed surface on particle ejection from a gas-solid fluidized bed is proposed. It is a statistical model based on detailed measurement of the relationship between bubble coalescence at the bed surface and particle swarm ejection caused by bubble eruption. By this model, the passing frequency of particle swarms in the freeboard, the maximum rise height of the particle swarms, and the entrainment rate below the TDH can be simulated, In particular, the effect of the superficial gas velocity on the passing frequency or the entrainment rate, which has not been evaluated by model analysis, can be predicted properly.