Gas-Liquid Mass Transfer in Stirred Non-Newtonian Corn-Starch Dispersions.

Vlaev, S. D.; Valeva, M.; Popov, Roman

doi:10.1252/jcej.27.723

Cited by 14 publications

(7 citation statements)

References 15 publications

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“…4, one can see that with increasing surfactant concentration and decreasing r, k L a decreased only slightly (typically up to 25 %). This result conformed to previous results on the effects of r on k L a in water-based gas-liquid dispersions [21]. It has been inferred that at surfactin concentration close to CMC, no significant concentration dependence of k L a occurs which would appear to be favorable for the biosurfactant lipopeptide production.…”

Section: The Lipopeptide Surfactant (Surfactin) Effectsupporting

confidence: 91%

Surfactant Effects on Aeration Performance of Stirred Tank Reactors

et al. 2008

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The effect of surfactants on aeration performance in stirred tank reactors (STR) at high rates of foaming is studied. The volumetric oxygen transfer coefficient (k L a) and foaming activity estimated as foaming height (H f ) were determined. Biotechnology of lipopeptide biosurfactants from aerobic organisms, e.g., Bacillus subtilis were addressed. Using model solutions of known foam-generating properties, high-molecular weight surfactin and low-molecular weight sodium dodecyl sulphate (SDS), as well as impellers of different types, with flat and fluidfoil blades, clues on the concentration dependence of STR oxygen transfer and foaming as well as options for foam reduction in the presence of biosurfactant were sought. In response to a two-fold decrease of surface tension by surfactin, k L a values decreased up to 30 % but remained within the range expected for the mixing system in water; the experiments with SDS showing stronger dependence on surfactant concentration and surface tension. Mixing of surfactant media by a standard six-blade disc turbine (RT) imposed rate limitations on gassing. A lowshear impeller Narcissus (NS) could be used to avoid bulk foam outflow, while preserving k L a values that remained unchanged. The 'power per unit volume' correlation of k L a in stirred tanks is tested in the presence of surfactin.

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Section: The Lipopeptide Surfactant (Surfactin) Effectsupporting

confidence: 91%

Surfactant Effects on Aeration Performance of Stirred Tank Reactors

et al. 2008

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“…16,17 On the other hand, many researchers have analysed the absorption experimental data using another kind of empirical correlation they have obtained, using dimensional analysis 18,19 based on well-known dimensionless numbers, which incorporate the operating variables and physical properties. The expression of this equation is shown in eqn (6):…”

Section: Resultsmentioning

confidence: 99%

Gas/liquid mass transfer processes in a carbon dioxide/alkane system

Gómez‐Díaz

Navaza

2005

J of Chemical Tech & Biotech

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A gas/liquid mass transfer process has been studied using carbon dioxide/alkane systems in a stirred vessel. Four linear alkanes (n-heptane, n-octane, n-decane and n-dodecane) have been used as the liquid phase in the present paper, and they have been employed to study the influence of the carbon length upon the mass transfer velocity. The mass transfer along the liquid phase has been studied using the mass transfer coefficient of the liquid phase, k L . Pure carbon dioxide has been employed as the phase in all cases for this reason. The effects of the power supplied to the liquid phase and the gas flow rate upon the absorption process have also been analysed. Finally, the equations that allow calculation of the mass transfer coefficients have been applied for these systems, with acceptable results.

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“…The absolute viscosity was calculated using eqn (4). Table 1 show the intrinsic viscosity values, the Mark-Houwink constants and the average molecular weight calculated for these polymers.…”

Section: Determination Of Intrinsic Viscosity and Average Molecular Wmentioning

confidence: 99%

Analysis of carbon dioxide gas/liquid mass transfer in aerated stirred vessels using non–Newtonian media

Gómez‐Díaz

Navaza

2004

J of Chemical Tech & Biotech

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Gas/liquid mass transfer has been investigated in an aerated stirred tank using non-Newtonian media and carbon dioxide as absorbent and gas phase respectively. The volumetric mass transfer coefficients at different operational variables have been measured. The non-Newtonian media (liquid phases) used were aqueous solutions of two polymers, carboxymethyl cellulose and alginate sodium salts. The influence upon the mass transfer of the rheological properties, polymer concentration, stirring rate and gas flow rate was studied. Kinematic viscosity and density experimental data were used to calculate the average molecular weight corresponding to the polymers employed. Reasonable agreement was found between the predictions of proposed models and the experimental data. The results shown in the present paper allow us to understand carbon dioxide transfer to a non-Newtonian liquid phase and to evaluate the effect of the liquid phase characteristics. The equations used in this paper allow accurate simulation of the transfer of a pure gas to a rheologically complex solution.

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Gas-Liquid Mass Transfer in Stirred Non-Newtonian Corn-Starch Dispersions.

Cited by 14 publications

References 15 publications

Surfactant Effects on Aeration Performance of Stirred Tank Reactors

Surfactant Effects on Aeration Performance of Stirred Tank Reactors

Gas/liquid mass transfer processes in a carbon dioxide/alkane system

Analysis of carbon dioxide gas/liquid mass transfer in aerated stirred vessels using non–Newtonian media

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