The Study of Corresponding Effects of anionic surfactant concentration and solute on Drop Size in a Mixer-Settler Extractor and Propose an Empirical Model


1 مهندسی شیمی

2 سازمان انرژی اتمی


Drop size distribution in a mixer-settler is an essential design parameter, as obtaining drop size distribution will result in optimum performance of equipment. In this paper for obtaining drop size, several experiments have been performed with a single stage horizontal mixer-settler. A video technique has been used in order to measure the drop size in the mixer-settler with the help of a digital camera. The present work examines the influence of an anionic surfactant concentration on the variation of drop sizes in the presence of solute. The results show that in low concentration of surfactant, a significant decrease in mean drop size is observed, but at high concentration, increasing of surfactant concentration doesn’t change mean drop size more. For different concentration of surfactant, a new empirical correlation is derived for estimation of mean drop size. These correlations have a good agreement with experimental data.


1- Lee, J. M. and Soong,Y. (1985). "Effects of surfactants on the liquid-liquid dispersion in agitated vessels."
Ind. Eng. Chem. Process Des. Deu., Vol. 24 ,PP. 118-121.
2- Hoffer, M. S. and Resnick, W. (1979). "A study of agitated liquid-liquid dispersions." Chem. Eng. Res. and
Des. Vol. 57, PP. 8-14.
3- Tcholakova, S., Denkov, N. D. and Danner, T. (2004). "Role of surfactant type and concentration for the
mean drop size during emulsification in turbulent flow." Langmuir, Vol.20, No. 18, PP. 7444-7458.
4- Skelland, A.H.P. and Jeffrey, S. (1998). "Transient drop size in agitated liquid-liquid systems, as influenced
by the direction of mass transfer and surfactant concentration." Ind. Eng. Chem. Res., Vol. 31, PP. 2556-
5- Zhou, G. and Kresta, S.M.(1998). "Evolution of drop size distribution in liquid-liquid dispersions for various
impellers.” Chem. Eng. Sci., Vol. 53, No. 11, PP. 2099-2113.
6- Desnoyer, C., Masbernat, O. and Gourdon, C. (2003). “Experimental study of drop size distributions at high
phase ratio in liquid–liquid dispersions.” Chem. Eng. Sci., Vol. 58, PP. 1353 – 1363.
7- Calabrese, R. V., Chang, T. P. K., and Dang, P. T. (1986).” Drop breakup in turbulent stirred-tank contactors.
”AICHE, Vol. 32, No .4, PP. 657–666.
8- Baldyga, J., Bourne, J. R., Pacek, A. W., Amanullah, A. and Nienow, A.W. (2001). “Effects of agitation on
drop size in turbulent dispersions: Allowance for intermittency.” Chem. Eng. Sci., Vol. 56, PP. 3377–3385.
9- Lagisetty, J. S. , Das, P. K., Kumar, R., and Ghandi, K. S. (1986).” Breakage of viscous and non-newtonian
drops in stirred dispersions.” Chem. Eng. Sci., Vol. 41, No. 1, PP. 65–72.
10- Doulah, M. S. (1975)." An effect of hold-up on drop sizes in liquid–liquid dispersions.” Industrial and
Engineering Chemistry Fundamentals, Vol. 14, No. 2, PP. 137–138.
11- Singh, K.K., Mahajani, S.M., Shenoy, K.T. and Ghosh, S.K. (2008). "Representative drop sizes and drop
size distributions in A/O dispersions in continuous flow stirred tank." Hydrometallurgy, Vol. 90, PP. 121-