Mass-transfer coefficients and equilibrium solubilities for fluid-supercritical-solvent systems by online near-IR spectroscopy

Zehnder, B.; Trepp, Ch.

doi:10.1016/0896-8446(93)90011-l

Cited by 20 publications

(8 citation statements)

References 6 publications

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“…Not unexpectedly, the correlations developed when a liquid-fluid interface is present (Zehnder and Trepp, 1993;Puiggené, 1996) lie near those developed here. In an earlier paper, we reasoned that an additional masstransfer resistance could be present in the liquid film in contact with the SCF, due to the large solubility of the high-pressure gas in the liquid.…”

Section: Sh ) F(rescgr)supporting

confidence: 80%

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Supercritical Fluid Extraction of Packed Beds: External Mass Transfer in Upflow and Downflow Operation

Vazquez

Larrayoz

Recasens

1996

Ind. Eng. Chem. Res.

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The effects of flow direction of solvent (CO 2 ) on the fluid-to-particle mass transfer were studied for packed beds of sintered porous pellets of two sizes (diameters of 1 and 2 cm) at conditions supercritical with respect to carbon dioxide using toluene and 1,2-dichlorobenzene as the impregnating solutes. Dynamic extraction experiments were performed in the laminar flow regime (Re ) 8-90) where both free and forced convection modes of mass transfer were found to be significant. Measured mass transfer coefficients showed an almost linear dependence on the Reynolds number (Re ≈0.9 ). Downflow of fluid had a strong effect on accelerating extraction rates, in particular at lower Reynolds numbers and for conditions near the critical point of CO 2 , where natural convection is dominant. Experimental mass-transfer coefficients were well correlated using a single general equation that accounts for both modes of mass transfer (free and forced convection) as well as for upflow or downflow operation (i.e., with gravity opposing or assisting forced convection). IE9601514 X Abstract published in Advance ACS Abstracts, September 15, 1996.

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Section: Sh ) F(rescgr)supporting

confidence: 80%

“…Thus, A ) 0.13 (Zehnder and Trepp, 1993), A ) 0.38 , A ) 0.35 (Steinberger and Treybal, 1960), A ) 1.1 (Wakao and Kaguei, 1982). Thus, A ) 0.13 (Zehnder and Trepp, 1993), A ) 0.38 , A ) 0.35 (Steinberger and Treybal, 1960), A ) 1.1 (Wakao and Kaguei, 1982).…”

Section: Mass-transfer Correlationsmentioning

confidence: 99%

Supercritical Fluid Extraction of Packed Beds: External Mass Transfer in Upflow and Downflow Operation

Vazquez

Larrayoz

Recasens

1996

Ind. Eng. Chem. Res.

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“…We did not find any work in the literature related to the binary solubilities studied in this work, although pure compound solubilities of α-tocopherol, ,− capsaicin, − or palmitic acid − in supercritical CO 2 have been already reported in the literature. The characteristics of these works are summarized in Table .…”

Section: Introductionmentioning

confidence: 84%

“…The characteristics of these works are summarized in Table . Solubilities of α-tocopherol were reported by Ohgaki et al, Chrastil, Zehnder and Trepp, Birtigh et al, Schaffner and Trepp, and Johannsen and Brunner . However, the system CO 2 + α-tocopherol exhibits vapor–liquid–liquid (VLLE) and vapor–liquid (VLE) equilibria. ,,,,− Pereira et al measured VLLE at temperatures from 292.15 to 304.25 K and determined the upper critical end point (UCEP) at 304.25 K for the system CO 2 + α-tocopherol.…”

Section: Introductionmentioning

confidence: 98%

“…Solubilities of α-tocopherol were reported by Ohgaki et al, Chrastil, Zehnder and Trepp, Birtigh et al, Schaffner and Trepp, and Johannsen and Brunner . However, the system CO 2 + α-tocopherol exhibits vapor–liquid–liquid (VLLE) and vapor–liquid (VLE) equilibria. ,,,,− Pereira et al measured VLLE at temperatures from 292.15 to 304.25 K and determined the upper critical end point (UCEP) at 304.25 K for the system CO 2 + α-tocopherol. Pereira et al, Meier et al, Moser and Trepp, Chen et al, Ŝkerget et al, and Fang et al reported VLE for this system at temperatures from 298.1 to 402 K. Regarding solubilities of capsaicin in supercritical carbon dioxide, these have been reported by Knez and Steiner, Hansen et al, de la Fuente et al, Elizalde-Solis and Galicia-Luna, , and Valderrama et al Meanwhile, solubilities of palmitic acid have been extensively reported by different authors: Ohgaki et al., Kramer and Thodos, Bamberger et al, Iwai et al., Maheshwari et al, Cho et al, Noh et al, Gordillo et al, Garlapati and Madras, , Brandt et al, Elizalde-Solis and Galicia-Luna, and Rosales-García et al These authors covered measurements at temperatures from 298 to 338 K. Bharath et al reported the presence of VLE for the system CO 2 + palmitic acid at higher temperatures of 353.15 and 373.15 K.…”

Section: Introductionmentioning

confidence: 98%

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Solubilities of Binary Systems α-Tocopherol + Capsaicin and α-Tocopherol + Palmitic Acid in Supercritical Carbon Dioxide

et al. 2019

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Solubilities of two binary mixtures (α-tocopherol + capsaicin and α-tocopherol + palmitic acid) in supercritical carbon dioxide (CO2) are reported in this work. Measurements were done in a semiflow apparatus at 308.15 and 328.15 K and in the pressure interval from 10 to 35 MPa. Equimolar mixtures of the solutes were prepared to perform solubility measurements. Each solubility point was replicated at least three times to check for the repeatability. Solubilities of α-tocopherol were higher than those of capsaicin for the ternary system. Meanwhile, for the binary mixtures α-tocopherol + palmitic acid, their solubilities in supercritical CO2 suffered a shift as temperature increased. The solubility of α-tocopherol was higher than that of palmitic acid at 308.15 K, and the vice versa occurred at 328.15 K. Solubilities were modeled by means of the Peng–Robinson equation of state using the van der Waals mixing rules with two adjustable parameters. Additionally, The Kumar and Johnston model was selected for the empirical correlation.

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Heat and Mass Transfer

Brunner

1994

Topics in Physical Chemistry

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Mass-transfer coefficients and equilibrium solubilities for fluid-supercritical-solvent systems by online near-IR spectroscopy

Cited by 20 publications

References 6 publications

Supercritical Fluid Extraction of Packed Beds: External Mass Transfer in Upflow and Downflow Operation

Supercritical Fluid Extraction of Packed Beds: External Mass Transfer in Upflow and Downflow Operation

Solubilities of Binary Systems α-Tocopherol + Capsaicin and α-Tocopherol + Palmitic Acid in Supercritical Carbon Dioxide

Heat and Mass Transfer

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