Effect of diffusivity on gas-side mass transfer coefficient
Chemical Engineering Science, Volume 21, Issue 4, 1966, Pages 361-365,
The effect of diffusivity on gas-side mass transfer coefficient was studied in an experimental bubble column. A fourteen-fold variation of diffusivity was obtained by using a variety of solutes and carrier gases. Both absorption and vaporization experiments were carried out, sometimes for the same solute. The absorption experiments were unambiguously gas-film controlled. The gas-side mass transfer coefficient varies as 0•5 power of the diffusivity under similar hydrodynamic conditions. Schmidt number is most unlikely to be the pertinent variable. It is also likely that the gas-side mass transfer coefficient varies as 0•33 power of the submergence and 0•75 power of the gas flow rate.
MM Sharma, Mashelka. RA, VD Mehta
British chemical engineering, January 1969
In mass transfer operations carried out in columns employing various types of tray, great deal more data than is presently available is required by designer; this article reports investigation of effect of gas velocity, diffusivity, submergence, physical properties of liquid, etc, on gas and liquid-side mass transfer coefficient and effective interfacial area in laboratory bubble cap plate columns; existing data cast light on performance of industrial-scale columns and are useful for design purposes.
Mehta, V. D., Ph.D. Tech. Thesis, University of Bombay, India 1970
Mass transfer in mechanically agitated gas—liquid contactors
Chemical Engineering Science, Volume 26, Issue 3, March 1971, Pages 461-479, DOI: https://doi.org/10.1016/0009-2509(71)83019-1
The theory of absorption with pseudo mth order irreversible reaction was used to obtain effective interfacial area, a, in mechanically agitated vessels. The liquid-side mass transfer coefficient, kLa was found by using the theory of absorption with slow chemical reaction. Eleven different systems were used to obtain a and four different systems were used to obtain kLa. The diameter of the contactor was varied from 12.5 cm to 70 cm.
The effect of the following variables on a and KLa was investigated: speed, type and diameter of the agitator; tank diameter, height of the agitator and height of the clear liquid from the base of the contactor; ionic strength, nature of ions, viscosity and surface tension of the liquid. It appears that values of a and kLa cannot be predicted a priori, as system properties have a profound effect on a and kLa. However, experiments can be done in a small agitated contactor (say, 20 cm dia. contactor) and scale-up can be done on the basis of equal tip speed divided by the square root of the contactor diameter, possibly with a fair degree of confidence.
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