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Showing papers on "Mass transfer coefficient published in 1981"


Journal ArticleDOI
TL;DR: In this paper, the effect of the aeration system and surface active agents on the mass transfer coefficient of tetrachloroethylene is studied and the stripping efficiencies of different types of gas-liquid contact devices used in water and waste water treatment are assessed.

183 citations


Journal ArticleDOI
H. Hikita, S. Asai, K. Tanigawa, K. Segawa, M. Kitao 
TL;DR: In this article, experimental data on the volumetric liquid-phase mass transfer coefficient kLa in 10 and 19 cm I.D. bubble columns with single-nozzle gas spargers were obtained with several gases and various pure liquids or aqueous nonelectrolyte solutions, and the effect of the physical properties of the gas and liquid on kLa was studied.

121 citations


Book ChapterDOI
01 Jan 1981
TL;DR: In this paper, the authors treat biochemicals as heterogeneous catalytic (HC) this paper in which physical mass transfer completely or significantly controls the overall rate of the process being promoted in the reactor.
Abstract: Biochemical reactors are treated as heterogeneous catalytic reactors in which physical mass transfer completely or significantly controls the overall rate of the process being promoted in the reactor. The treatment used to develop basic design strategies takes into account the special constraints imposed by biological and biochemical phenomena on the systems.

120 citations


Journal ArticleDOI
TL;DR: In this article, the intrinsic kinetic data from the process kinetic measurements in a trickle-bed reactor was used to evaluate the effect of axial dispersion on mass transfer coefficients, which were then used to calculate the intrinsic transfer coefficients.

100 citations


Book ChapterDOI
TL;DR: In this paper, the authors discuss interphase reactions and describe the phenomenon of mass transfer in liquid-liquid dispersions, and present several useful mathematical models with the help of several useful analytical tools.
Abstract: Publisher Summary This chapter discusses interphase reactions and describes the phenomenon of mass transfer in liquid–liquid dispersions. The rate of interphase mass transfer is affected by the physical and chemical characteristics of the system and the mechanical features of the equipment. The former include viscosities and densities of the phases, interfacial surface properties, diffusion coefficients, and chemical reaction coefficients. The latter include the type and diameter of the impeller, vessel geometry, the flow rate of each phase, and the rotational speed of the impeller. When slow reactions in either phase control the rate of transfer, micromixing of the dispersed or continuous phase is not important. The total interfacial surface area is important and can be related to the power expended. Micromixing and macromixing of the dispersed phase can significantly affect the extent of conversion and selectivity. Accordingly, dispersion phenomena such as coalescence and breakage of droplets, and drop size distribution take place. Mass transfer in liquid–liquid dispersions and interphase reactions analysis are presented in this chapter with the help of several useful mathematical models.

84 citations



Journal ArticleDOI
TL;DR: In this article, the authors developed a realistic mechanism involving periodically varying rates of surface renewal associated with droplet circulation through varying degrees of turbulence around the vessel and obtained relationships for optimized design and scale-up.
Abstract: Continuous-phase mass transfer coefficients and drop sizes in agitated vessels are correlated with operating variables and physical properties of liquid-liquid systems. In formulating mass transfer coefficients, a realistic mechanism has been developed, involving periodically varying rates of surface renewal associated with droplet circulation through varying degrees of turbulence around the vessel. Relationships are obtained for optimized design and scale-up.

69 citations


Journal ArticleDOI
TL;DR: In this article, a bisolute system of dissolved organics on activated carbon is measured in fixed beds and three different models with different assumptions about diffusion in the liquid filled pores and diffusion on the surface in series with external film diffusion.

45 citations


Journal ArticleDOI
TL;DR: In this paper, mass transfer and pressure drop behavior of turbulence promoters in a rectangular channel is determined using the electrochemical method at macroscopic and microscopic scales simultaneously, and the average mass transfer is used to test the validity of a model based on application of a mass-momentum transfer analogy to flow over a rough surface.

42 citations


Journal ArticleDOI
TL;DR: In this paper, mass transfer measurements in two bubble columns with an inner diameter of 100 resp. 140 mm with the systems air/water/carbon dioxide and nitrogen/n-propanol/ carbon dioxide have been evaluated with the axial dispersion model.

40 citations


Journal ArticleDOI
TL;DR: In this article, the rates of gas induction, effective interfacial area a, and liquid-side mass transfer coefficient kLa were obtained from 100 × 100, 140 × 140, 172 × 172 and 380 × 380 mm × mm Denver-type flotation cells.

Journal ArticleDOI
TL;DR: In this article, a new method has been developed for the measurement of overall volumetric mass transfer coefficient (KLa) in gas-liquid-solid systems based on the examination of gas phase dynamics in a three-phase contactor and consists of measuring continuously the response of the outlet gas composition to a step input change of CO2 in the inlet gas stream.
Abstract: A new method has been developed for the measurement of overall volumetric mass transfer coefficient (KLa) in gas-liquid-solid systems. This method is based on the examination of gas phase dynamics in a three-phase contactor and consists of measuring continuously the response of the outlet gas composition to a step input change of CO2 in the inlet gas stream. The advantages and limitations of the new method are presented and its sensitivity is discussed on the basis of model predictions. Preliminary results on the implementation of the CO2 method are also reported. Experimental data obtained in a nonviscous electrolyte solution show that the proposed method compares favorably with the conventional dissolved oxygen technique, provided that a correction is made to take account of the difference in diffusivity of oxygen and carbon dioxide.

Book ChapterDOI
01 Jan 1981
TL;DR: In this article, the extent of absorption into the sludge solids is given by a distribution equilibrium between the solids and the liquid and can be predicted from the lipophility of the substances as measured by their n-octanol-water distribution coefficient.
Abstract: Non-biodegradable volatile organic pollutants may be efficiently eliminated from waste water in an activated sludge process either by absorption into the biomass of the sludge or by volatilization concomitant with the oxygen transfer to the mixed liquor. The extent of absorption into the sludge solids is given by a distribution equilibrium between the solids and the liquid and can be predicted from the lipophility of the substances as measured by their n-octanol-water distribution coefficient. The volatilization of less lipophilic substances can be interrelated to the mass transfer coefficient of oxygen and can be predicted from the critical volume of these substances. The validity of these non-biological elimination mechanisms was checked in two semi-technical activated sludge processes operated in parallel by establishing a mass balance for four selected indicator compounds indigenously present in municipal sewage. Volatilization and absorption into biomass are also of importance in predicting the fate and residence time of refractory organic substances in natural waters.

Journal ArticleDOI
TL;DR: In this paper, an analysis of heat and mass transfer of extruded corn meal is presented, where both liquid and vapor fluxes can be expressed in terms of the same driving forces, namely, temperature and equilibrium moisture content gradients.
Abstract: This work presents an analysis of heat and mass transfer of extruded corn meal. Isotherm, thermal conductivity, drying and center temperature data were experimentally obtained for the cylindrically extruded product. Modeling of the drying process was made by incorporating the mechanistic and irreversible thermodynamics approaches for determining heat and mass transfer in capillary-porous media. The proposed model shows that both liquid and vapor fluxes can be expressed in terms of the same driving-forces, namely, temperature and equilibrium moisture content gradients. A search technique allowed for the evaluation of both liquid and vapor conductivities.

Journal ArticleDOI
TL;DR: In this paper, a simple approximate formula for calculating the mass transfer coefficient for a moving reactive particle, the surface of which is the site of a heterogeneous chemical reaction with arbitrary kinetics, was proposed.
Abstract: A simple approximate formula is proposed for calculating the mass-transfer coefficient for a moving reactive particle, the surface of which is the site of a heterogeneous chemical reaction with arbitrary kinetics.


01 Jul 1981
TL;DR: In this article, a relationship is given for predicting heat and mass transfer coefficients between the elements of a packing of equal sizes and a flowing fluid in the kinetics-controlled zone of heat transfer, i.e., at values of the Peclet numbers larger than 500 to 1000.
Abstract: A relationship is given for predicting heat and mass transfer coefficients between the elements of a packing of spheres of equal sizes and a flowing fluid in the kinetics-controlled zone of heat and mass transfer, i.e., at values of the Peclet numbers larger than 500 to 1000. The predictions are compared with measured values collected from the literature extending over ranges of the Prandtl or Schmidt numbers from 0.7 to 104, void fractions from 0.26 to 0.935, and Reynolds numbers up to 2 x 10/sup 4/. 30 references.

Journal ArticleDOI
TL;DR: In this article, it was shown that interphase nitrogen transport may have a significant influence on the rate of interphase oxygen transport, and thereby also on the value of the volumetric mass transfer coefficient of oxygen, kla, determined in mechanically agitated bubble fermentors.
Abstract: It has been shown both theoretically and experimentally that interphase nitrogen transport may have a significant influence on the rate of interphase oxygen transport, and thereby also on the value of the volumetric mass transfer coefficient of oxygen, kla, determined in mechanically agitated bubble fermentors using the variants of dynamic method presented in the literature. The experiments were carried out in 1M KCI solution at five stirrer frequencies and two gas inlet levels. The gas interchanges were performed either without interrupting the aeration and agitation of the charge (A) or with the aeration and agitation of the charge turned on at the same time (B). The applied variants of the interchange were N2→ O2→, O2→ N2, N2→ air, air→ N2, O→ O2, and O→ air. In the two last variants the oxygen dissolved in the charge was removed by reacting with sulfite ions. The kla values calculated by allowing for the nitrogen transport for procedure A were approximately equal to the values obtained by disregarding the nitrogen transport, whereas those for procedure B were higher (up to 40%), than the values obtained disregarding the nitrogen transport.

Journal ArticleDOI
TL;DR: In this article, it is shown that deviations of real from assumed mixing behaviour in both phases as well as rather small errors in the concentration of the liquid phase may result in deviations up to a factor of 5-10.

Journal ArticleDOI
TL;DR: In this paper, new models are developed to analyze the wet spinning process, which involve a formulation of simultaneous overall mass, force, and solvent mass transfer balances, which is equivalent to the Kase-Matsuo melt spinning model.
Abstract: New models are developed to analyze the wet spinning process. These involve a formulation of simultaneous overall mass, force, and solvent mass transfer balances. In the first-order model, internal concentration gradients and mass transfer resistance within the fiber are neglected. It is equivalent to the Kase–Matsuo melt spinning model. In the second-order model, concentration gradients and diffusion within the fiber are included. Comparison is made with an experimental study of wet spinning nylon-66 fibers. The first-order model seriously underpredicts final fiber diameter under conditions of specified spinline tension and spinning efflux. The second-order model gives better agreement between theory and experiment.

Journal ArticleDOI
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.

Journal ArticleDOI
TL;DR: In this paper, an analytical solution of the governing differential equation for gas absorption in laminar falling films with the first order homogeneous reaction and external gas phase mass transfer resistance is shown.

Journal ArticleDOI
TL;DR: In this article, a model based on equilibrium thermodynamics was developed to analyse the EXCOBULLE experiments, where large rates of heat and mass transfer are required to obtain agreement with the experiments.

Journal ArticleDOI
TL;DR: In this paper, a linear hydrodynamic stability analysis of a liquid jet in relative motion through a second liquid in the presence of mass transfer between them predicts a significant effect of the mass transfer direction and driving force and solute adsorption on jet length.

Journal ArticleDOI
TL;DR: In this article, the minimum vibration speed for complete suspension and for the mass transfer coefficient have been obtained in terms of the operating variables and the power requirement per unit volume of fluid content.

Proceedings ArticleDOI
09 Mar 1981
TL;DR: In this article, the authors measured the local heat transfer coefficient of full-coverage film-cooled wall by using the law of analogy to mass transfer and confirmed experimentally that the local Stanton number is a linear function of non-dimensional temperature ratio.
Abstract: The local heat transfer coefficient of full-coverage film-cooled wall has been measured by using the law of analogy to mass transfer. For this experiment, the technique of sublimation of naphthalene was used. The geometric shape of FCFC plate and the experimental condition were the same as those in Part 1. From these experiments, the effects of the mass flux ratio and non-dimensional injection wall temperature ratio on the local Stanton number are made clear and it is confirmed experimentally that the local Stanton number is a linear function of non-dimensional temperature ratio as expected from the analysis. Furthermore, the local heat transfer coefficient on the backside surface has been obtained and a technique for the improvement of cooling effectiveness is discussed.Copyright © 1981 by ASME

Journal ArticleDOI
TL;DR: In this article, the first absolute and second and third central moments of the chromatographic curv from a non-isobaric column for the Kubin and Kucera model (axial dispersion, external diffusion, internal diffusion, rate of adsorption) were derived.

Journal ArticleDOI
TL;DR: In this paper, a graphical method of determining the Michaelis-Menten constant free of the external mass transfer resistance for a packed bed immobilized enzyme system was illustrated with examples from three different enzyme reactions.
Abstract: A graphical method of determining the Michaelis-Menten constant free of the external mass transfer resistance for a packed bed immobilized enzyme system was illustrated with examples from 3 different enzyme reactions. The intercept at the ordinate obtained by the straight line extrapolation of data points in the plot of apparent Km value vs. the reciprocal of superficial velocity in column allowed an easy calculation of Km free of external mass transfer resistance. An asymptotic value of apparent Km value at infinite zero superficial velocity was ascribed to the fact that the mass transfer coefficient kL, approached a definite value at this condition.

Journal ArticleDOI
TL;DR: In this article, the effect of the wetting efficiency on the performance of a trickle-bed reactor may be significant, and analytical solutions are derived for the outlet concentrations of reactants involved in a first-order reaction.

Journal ArticleDOI
TL;DR: The kinetic and equilibrium constants for the hydrogenation of soybean oil on a commercial nickel catalyst in a 300-ml Parr batch reactor were determined in this paper, where they were used to calculate the hydrogen gas absorption coefficients by coupling mass transfer with reaction rate based on a Langmuir Hinshelwood model.
Abstract: The kinetic and equilibrium constants were determined for the hydrogenation of soybean oil on a commercial nickel catalyst in a 300-ml Parr batch reactor. These constants were used to calculate the hydrogen gas absorption coefficients by coupling mass transfer with reaction rate based on a Langmuir Hinshelwood model. The activation energy for the rate-determining step was 23 kcal/g mol whereas the adsorption energy for hydrogen was −12.5 kcal/g mol. The gas absorption coefficients varied between 0.3 to 0.7 min−1 as the temperature ranged between 140–180 C.