Mass transfer in gas-fluidized beds: measurement of actual driving forces

Hsiung, Thomas H.; Thodos, George

doi:10.1016/0009-2509(77)80223-6

Cited by 30 publications

(17 citation statements)

References 5 publications

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“…Careful selection of the operating conditions (T ≈ 65°C) and of the inert material (glass beads and dense alumina) could minimize these problems. The experimental results were in line with results of Hsiung & Thodos (1977). In particular, no effect of the fluidizing velocity on the mass transfer coefficient was observed over the complete range of bed materials.…”

Section: Sublimation Of Solid Particlessupporting

confidence: 80%

“…In particular, no effect of the fluidizing velocity on the mass transfer coefficient was observed over the complete range of bed materials. The experimental data of this work and those of Hsiung & Thodos (1977) were correlated by the following empirical expression (rearranged here in terms of the Sherwood number): , and the Reynolds number at minimum fluidization was referred to the inert particle diameter Carvalho (1988) made similar experiments with somewhat heavier naphthalene particles, and substantially confirmed results by Prins et al (1985). Pal'chenok & Tamarin (1985) and Tamarin et al (1985) measured the mass transfer coefficients of single particles composed of a naphthalene spherical shell placed over a core made of different materials in order to vary the total density of the active particles.…”

Section: Sublimation Of Solid Particlesmentioning

confidence: 96%

“…3, as reported by the authors in their paper. Eqs 2 (Hsiung & Thodos, 1977) and 7 (Joulié et al, 1997) both significantly overpredict the Sherwood number. In Eq.…”

Section: Comparison Of Available Correlations With Experimental Datamentioning

confidence: 99%

“…This result was explained by the reduced volume available for diffusion because of the presence of the inert particles, and the use of an effective diffusion coefficient through the bed interstices was suggested. Hsiung & Thodos (1977) diluted few naphthalene spheres in a bed of inert particles of the same size and density. The inert particles were beads of styrene divinylbenzene copolymer, which were claimed not to adsorb appreciably naphthalene vapour after an initial exposure.…”

Section: Sublimation Of Solid Particlesmentioning

confidence: 99%

See 3 more Smart Citations

Mass Transfer around Active Particles in Fluidized Beds

Scala¹

2011

Mass Transfer in Multiphase Systems and Its Applications

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Section: Sublimation Of Solid Particlessupporting

confidence: 80%

Section: Sublimation Of Solid Particlesmentioning

confidence: 96%

“…3, as reported by the authors in their paper. Eqs 2 (Hsiung & Thodos, 1977) and 7 (Joulié et al, 1997) both significantly overpredict the Sherwood number. In Eq.…”

Section: Comparison Of Available Correlations With Experimental Datamentioning

confidence: 99%

Section: Sublimation Of Solid Particlesmentioning

confidence: 99%

See 2 more Smart Citations

Mass Transfer around Active Particles in Fluidized Beds

Scala¹

2011

Mass Transfer in Multiphase Systems and Its Applications

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“…Hsiung and Thodos [45] studied mass transfer in a fluidized bed comprising of napthalene spheres as active particles and beads of styrene divinylbenzene as inert particles with air as the fluidizing medium. Based on the study, they presented the following empirical correlation:…”

Section: Convective Mass Transfer Modelsmentioning

confidence: 99%

Convective Heat and Mass Transfer Modeling in Gas-Fluidized Beds

Yusuf¹,

Melaaen

Mathiesen

2005

Chem. Eng. Technol.

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This review examines selected mechanistic and empirical models reported in the literature to predict convective heat and mass transfer coefficients in gas-fluidized beds. The role of hydrodynamics in heat and mass transfer is briefly outlined before embarking on the modeling approaches. Both bed to wall and interphase heat transfer, are considered. In bed to wall heat transfer, the main focus of the review is the modeling of particle convective components, based on surface renewal. The concepts of transient and local heat transfer models are also discussed briefly. In the case of mass transfer, only interphase transfer is considered. Emphasis is placed on models based on combustion where mass transfer is seen to occur from a few active particles contained in a fluidized bed of inert particles.

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Devolatilization and combustion of large coal particles in a fluidized bed

1990

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Devolatihdtion and combustion of large particles of Eastern Canadian coals (Evans and Minto), 5-50 mm dia., were studied in a bench-scale atmospheric fluidized bed reactor at 1023-1 173 K with 0.5 mm sand particles as the bed material. The devolatilization time, mass loss history, changes in proximate volatiles content and C/H mass ratio, and temperature history at the centre of the particle during devolatilization were determined. The mass loss during devolatilization is correlated with the proximate volatiles content of the parent coal. The devolatilization time is correlated with the initial particle diameter by a power-law relation with an exponent of 1.54-1.64. The results show insignificant effect of superficial velocity on devolatilization.On a CtudiC la dtvolatilisation et la combustion de larges particules de charbon de I'Est du Canada (Evans et Minto), dc 5 a 50 mm de diamktre, dans un reacteur B lit fluidis6 atmospherique de laboratoire, 2i des tempkratures de 1023 a I173 K et avec des particules de sable de 0,5 rnm de diamhre comme matCriau du lit. On a determine le temps de devolatilisation, l'histoire de la perte de masse, les changements dans la teneur des volatils voisins et le bilan massique C/H ainsi que I'histoire de la temperature au centre de la particule durant la dbvolatilisation. La perte de charge durant la dkvolatilisdtion est corrClCe ? i la teneur des volatils voisins d'un chdrbon apparentk. Le temps de dtvolatilisation est corrCIC au diamktre initial des particules par une relation de loi de puissance avec un exposant de 134-I ,64. Les rtsultats montrent un effet non significatif de la vitesse superficielle sur la devolatilisation.

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Mass transfer in gas-fluidized beds: measurement of actual driving forces

Cited by 30 publications

References 5 publications

Mass Transfer around Active Particles in Fluidized Beds

Mass Transfer around Active Particles in Fluidized Beds

Convective Heat and Mass Transfer Modeling in Gas-Fluidized Beds

Devolatilization and combustion of large coal particles in a fluidized bed

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