Analogy between Heat Transfer and Mass Transfer

Bedingfield, Charles Hosmer; Drew, T. B.

doi:10.1021/ie50486a029

Cited by 79 publications

(20 citation statements)

References 7 publications

(9 reference statements)

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“…Such a situation can occur, for instance, in transpiration or ablative coolhave pointed out t f e difficulty of treating simultaneous to mass transfer, and one of t g e best surveys on this subtransfer was affected by t K e diffusion rates of each coming. Bedingfield and Drew (19) derived a correction factor for direct analogy between mass and heat transfer in binary systems and using dilute systems obtained good correlation. Heinrich ( 2 0 ) , working with a more concentrated system, was unable to find a eneral analogy.…”

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confidence: 98%

Forced and natural convective mass transfer in multicomponent gaseous mixtures

Carlton

Oxley

1967

AIChE Journal

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The use of the Chilton-Colburn analogy to obtain an effective film thickness over which the Stefan-Maxwell equations can be integrated was confirmed for binary mixtures and found opplicoble for ternary, quaternary, and presumably higher order mixtures under conditions of nonequimolal counterdiffusion in a differential convective flow system. A method of averaging binary diffusivities was developed for use in computing the Schmidt number in these multicomponent systems. It was also found necessary to modify the usual Shenvood number, if there was a large molecular weight c h n g e across the diffusion barrier when the Chilton-Colburn analogy was employed.One of the most dacult current problems in chemical engineering involves mass transfer in multicomponent gaseous mixtures under conditions of convective flow. For many years the concept of a film resistance to diffusion, originally proposed by Noyes and Whitney ( 1 ) and subsequently extended by Nernst ( 2 ) , was sufficient for most applications involving systems with two components or one diffusing component in a mixture of nondiffusing components ( 3 ) . Whitman ( 4 ) proposed the additive resistances of these films, and Fischbeck (5) and Tu et al. (6) extended their utility to interfaces at which a chemical reaction is occurrin However, Bischoff and Froment (7) reaction and kinetic resistances for real systems without the use of computational equipment. In recent years the penetration theory of Higbie ( 8 ) , with suitable modifications, has been gaining in popularity (9 to 1 2 ) , and Sherwood et al. have recently suggested turbulent film (13, 1 4 ) and parallel eddy and molecular diffusion ( 1 5 ) models. However, the film concept is still widely used industrially and is quite satisfactory for many applications.The use of analogies between momentum, heat, and mass transfer is especially he1 ful in defining a resistance ject is by Sherwood ( 1 6 ) . However, if these analogies are to be employed with the kinetic theory of gases to solve multicomponent diffusion problems, a model such,as eff ective f i l m , surface renewal, etc., must be employed. In addition, multicomponent systems present problems, because the analogies between momentum and heat transfer no longer bear a direct similarity with mass transfer. The diffusion rates of various components in a mixture are not necessarily directly related to the heat and momentum transport rates. For instance, the diffusion rates of a given component, or of the mixture as a whole, can vary in both sign and magnitude under conditions where the heat or momentum transfer is relatively invariant. Ackerman (1 7) first reported this difficult and showed how total heat ponent, as well as by the transport parameters of the bulk stream. Mickley et al.( 1 8 ) extended this concept to the case where the flow to or from an interface was essentially independent of bulk stream conditions. Such a situation can occur, for instance, in transpiration or ablative coolhave pointed out t f e difficulty of treating simultaneous to ma...

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Forced and natural convective mass transfer in multicomponent gaseous mixtures

Carlton

Oxley

1967

AIChE Journal

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“…The correlation presented for estimating kG was based on data obtained with air as the inert gas a t atmospheric pressure and room temperatures. although this equation correlated the data of several previous investigators, obtained under similar conditions, thrre were no data to provide a suitable check on the ability of the equation to predict kG over the wide range of temperatures, pressures and gas physical properties that may be encountered in design problems.The object of this work is to study the effect of gas physical properties, temperature, and pressure on gas-phase mass transfer coefficients and the usefulness of Equation (1) for predicting coefficients under a variety of conditions.An examination of the terms in Equation (1) indicates that kG should be almost indcprndent of temperature, being approximatcly proportional to To 11. The methods for estimating effective interf:icial areas a prcsentcd previously Decreases in kGa with increasing temperature for ammonia absorption work have been reported by Kowalke, Hougen, and Watson (7), Dodge and Dwyer (S), and Molstad, McKinney, and Abbey (Q), these decreases ranging from 0.2 to 0.8 %/"C. based on the outlet water temperature.…”

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“…I n ammonia absorption it is possible to obtain a rise in water temperature when the ammonia dissolves and a fall in water temperature if the air used is not saturated. I t should be pointed out that the effect of tempcrature on kG should be determined by employing varying gasphase tcmprratures rather than temperatures based on conditions in the liquid phase.For low concentrations of the solute in the carrier gas, Equation (1) predicts that kc should be inversely proportional to total pressure. This has been found to hold for absorption in packed columns over the range of 1 t o 14 atm.…”

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confidence: 99%

“…The object of this work is to study the effect of gas physical properties, temperature, and pressure on gas-phase mass transfer coefficients and the usefulness of Equation (1) for predicting coefficients under a variety of conditions.…”

mentioning

confidence: 99%

“…and show the expected effect of pressure. Both sets of data mentioned were obtained a t low solute concentration, thus leaving in doubt the use of PBjr in Equation (1) in place of the total pressure.…”

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confidence: 99%

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Performance of packed columns. IV. Effect of gas properties, temperature, and pressure on gasphase mass transfer coefficients

Shulman

Margolis

1957

AIChE Journal

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To test the applicability, over a wide range of temperatures, pressures, and gas physical properties, of the mass transfer correlation presented earlier, 0.5-in. naphthalene Berl saddles were vaporized into air, carbon dioxide, and Freon-12 in a 4.0-in. column. Temperatures from 15" to 73°C. and pressures from 0.26 to 1 atm. were covered.The correlation was found to represent all the experimental data when the surface temperature of the naphthalene was used to evaluate the correct driving force.This correlation, when combined with effective interfacial areas presented previously, makes it possible to estimate the volumetric mass transfer coefficient, &a, for any gasliquid-solute system. I n the first three papers (10, 11, 1g) of this series devoted to packed columns, a method was proposed for predicting over-all mass transfer coefficients KGu from gas-and liquid-phase coefficients kG and kL and the effective interfacial area a. The correlation presented for estimating kG was based on data obtained with air as the inert gas a t atmospheric pressure and room temperatures. although this equation correlated the data of several previous investigators, obtained under similar conditions, thrre were no data to provide a suitable check on the ability of the equation to predict kG over the wide range of temperatures, pressures and gas physical properties that may be encountered in design problems.The object of this work is to study the effect of gas physical properties, temperature, and pressure on gas-phase mass transfer coefficients and the usefulness of Equation (1) for predicting coefficients under a variety of conditions.An examination of the terms in Equation (1) indicates that kG should be almost indcprndent of temperature, being approximatcly proportional to To 11. The methods for estimating effective interf:icial areas a prcsentcd previously Decreases in kGa with increasing temperature for ammonia absorption work have been reported by Kowalke, Hougen, and Watson (7), Dodge and Dwyer (S), and Molstad, McKinney, and Abbey (Q), these decreases ranging from 0.2 to 0.8 %/"C. based on the outlet water temperature. These data cannot be used for predicting the effect of temperature or checking Equation (1) because the gas temperatures were not varied over a wide range and the water temperature variations are peculiar to the conditions under which the columns were operated. I n ammonia absorption it is possible to obtain a rise in water temperature when the ammonia dissolves and a fall in water temperature if the air used is not saturated. I t should be pointed out that the effect of tempcrature on kG should be determined by employing varying gasphase tcmprratures rather than temperatures based on conditions in the liquid phase.For low concentrations of the solute in the carrier gas, Equation (1) predicts that kc should be inversely proportional to total pressure. This has been found to hold for absorption in packed columns over the range of 1 t o 14 atm. by Zabban and Dodge (14). Goodman's (4) unpublished data for the va...

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Simultaneous Heat and Mass Transfer

Wenzel

2000

Kirk-Othmer Encyclopedia of Chemical Technology

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In process operations where material is transferred between phases, usually between liquid and vapor phases, the transport process may be described in terms of heat transfer and mass transfer. When both expressions are developed and handled simultaneously, the resulting equations show that heat and mass transfer affect each other. Equations applied to humidification and dehumidification processes are presented. These expressions could equally well be applied to drying, evaporation, or crystallization processes. The conceptual design of counterflow cooling towers or dehumidification towers is discussed, as are the mechanical and operating features of these columns, costs, and environmental impacts. In all of these processes the air–water system is usually of concern. Thus the properties of moist air are developed and displayed on psychrometric charts.

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Analogy between Heat Transfer and Mass Transfer

Cited by 79 publications

References 7 publications

Forced and natural convective mass transfer in multicomponent gaseous mixtures

Forced and natural convective mass transfer in multicomponent gaseous mixtures

Performance of packed columns. IV. Effect of gas properties, temperature, and pressure on gasphase mass transfer coefficients

Simultaneous Heat and Mass Transfer

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