Design of Cooler Condensers for Mixtures of Vapors with Noncondensing Gases

Colburn, A. P.; Hougen, O. A.

doi:10.1021/ie50299a011

Cited by 303 publications

(91 citation statements)

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“…An early attempt at predicting heat transfer coefficients in these mixtures was performed by Colburn [8], who noted when even small amounts of air were present in steam condensers, condensation rates were significantly lower than those predicted by Nusselt theory [9]. A significant body of work was developed by…”

Section: Condensation In the Presence Of Noncondensable Gasesmentioning

confidence: 99%

Entropy generation in condensation in the presence of high concentrations of noncondensable gases

Thiel

Lienhard

2012

International Journal of Heat and Mass Transfer

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The physical mechanisms of entropy generation in a condenser with high fractions of noncondensable gases are examined using scaling and boundary layer techniques, with the aim of defining a criterion for minimum entropy generation rate that is useful in engineering analyses. This process is particularly relevant in humidification-dehumidification desalination systems, where minimizing entropy generation per unit water produced is critical to maximizing system performance. The process is modeled by a consideration of the vapor/gas boundary layer alone, as it is the dominant thermal resistance and, consequently, the largest source of entropy production in many practical condensers with high fractions of noncondensable gases. Most previous studies of condensation have been restricted to a constant wall temperature, but it is shown here that for high concentrations of noncondensable gases, a varying wall temperature greatly reduces total entropy generation rate. Further, it is found that the diffusion of the condensing vapor through the vapor/noncondensable mixture boundary layer is the larger and often dominant mechanism of entropy production in such a condenser. As a result, when seeking to design a unit of desired heat transfer and condensation rates for minimum entropy generation, minimizing the variance in the driving force associated with diffusion yields a closer approximation to the minimum overall entropy generation rate than does equipartition of temperature difference.

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Section: Condensation In the Presence Of Noncondensable Gasesmentioning

confidence: 99%

Entropy generation in condensation in the presence of high concentrations of noncondensable gases

Thiel

Lienhard

2012

International Journal of Heat and Mass Transfer

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“…Only two examples of calculations concerning a condensing heat exchanger used for flue gas from coal combustion were found in the literature (Jeong et al, 2010;Levy et al, 2008). Both models referred to the well-known Colburn-Hougen model (Colburn and Hougen, 1934) and introduced various modifications to it. In other works, mathematical models of condensing heat exchangers used at combustion of fuel oil (Ball et al, 1984;Osakabe, 2000) or gas (Jia et al, 2001;Liang et al, 2007;Shi et al, 2011) were presented.…”

Section: Cpeczasopismapanpl; Degruytercom/view/j/cpementioning

confidence: 99%

“…In the Colburn's method (Colburn and Hougen, 1934), the following values must be known for the dry part of the exchanger:…”

Section: Mathematical Modelsmentioning

confidence: 99%

Methods of Thermal Calculations for a Condensing Waste-Heat Exchanger

Rączka¹,

Wójs²

2014

Chemical and Process Engineering

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The paper presents the algorithms for a flue gas/water waste-heat exchanger with and without condensation of water vapour contained in flue gas with experimental validation of theoretical results. The algorithms were used for calculations of the area of a heat exchanger using waste heat from a pulverised brown coal fired steam boiler operating in a power unit with a capacity of 900 MW e . In calculation of the condensing part, the calculation results obtained with two algorithms were compared (Colburn-Hobler and VDI algorithms). The VDI algorithm allowed to take into account the condensation of water vapour for flue gas temperatures above the temperature of the water dew point. Thanks to this, it was possible to calculate more accurately the required heat transfer area, which resulted in its reduction by 19 %. In addition, the influence of the mass transfer on the heat transfer area was taken into account, which contributed to a further reduction in the calculated size of the heat exchanger -in total by 28% as compared with the Colburn-Hobler algorithm. The presented VDI algorithm was used to design a 312 kW pilot-scale condensing heat exchanger installed in PGE Belchatow power plant. Obtained experimental results are in a good agreement with calculated values.

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“…(28)(29)(30)(31)(32)(33)(34)(35) Noncondensible gases can impose a significant resistance to condensation. (1,9,(36)(37)(38)(39)(40) Sparrow and Lin(41·) analytically described film condensation in the presence of noncondensible gases to show the importance of gas diffusion normal to the surface and free convection parallel to the condensate surface. They only applied their theory, however, to steam condensation in the presence of air.…”

Section: B Summary Of Literature Surveymentioning

confidence: 99%

CONDENSATION OF METAL VAPORS: MERCURY AND THE KINETIC THEORY OF CONDENSATION (thesis)

Wilhelm¹

1964

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Design of Cooler Condensers for Mixtures of Vapors with Noncondensing Gases

Cited by 303 publications

References 1 publication

Entropy generation in condensation in the presence of high concentrations of noncondensable gases

Entropy generation in condensation in the presence of high concentrations of noncondensable gases

Methods of Thermal Calculations for a Condensing Waste-Heat Exchanger

CONDENSATION OF METAL VAPORS: MERCURY AND THE KINETIC THEORY OF CONDENSATION (thesis)

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