Iranian Journal of Chemical Engineering (IJChE)

Abstract Sauter mean drop sizes have been measured in a pulsed packed extraction column for two liquid systems with and without mass transfer conditions. The effects of pulsation intensity, phase flow rates, and interfacial tension on drop size have been investigated under a variety of operating conditions. The drop size is influenced mainly by pulsation intensity and interfacial tension. Significant, but weaker, are the effects of continuous and dispersed phase flow rates. A precise correlation is proposed for predicting mean drop size in terms of operating variables, physical properties of the liquid systems and mass transfer direction. Good agreement between prediction and experiments is found for all operating conditions that were investigated.

Abstract An experimental study of the phase inversion phenomenon was carried out in a rotating disc contactor (9.3 cm diameter). The effect of energy input via agitation and physical properties of the liquids upon inversion holdup and also delay time (time of inversion) was investigated at the constant input flow rate of the dispersed phase under no mass transfer conditions. Water was chosen as the continuous phase, and it was kept stagnant inside the column. The critical dispersed phase holdup was found to be decreased by increasing the energy input via agitation. It was observed that the lower
both the interfacial tension and the density difference of two phases, the greater the resistance of the system to inversion. Moreover, a reduction in delay time was observed by increasing the energy input via agitation.

Abstract "> Phase inversion phenomenon occurs in many industrial processes including liquidliquid dispersions. Some parameters such as energy input or the presence of mineral compounds in the system affect this phenomenon. The aim of this research is to study the speed of rotation or energy input at a range of 400 to 800 rpm in a batch liquid-liquid system containing toluene and water. The presence of sodium chloride and magnesium sulphate in the system was also studied. It was shown that the increase of energy input had a more obvious effect on oil in water (O/W ) dispersion at lower values of holdup. It was also shown that the ambivalence (o/w → w/o) region of the phase inversion curve shifted downward and became wider as a result of the decrease in interfacial tension. It was observed that inorganic salt, used in both single and dual (mixed) shapes, enhanced phase inversion for O/W dispersion. Therefore, the greater the ionic strength of salt, the greater the tendency to phase inversion is.

Abstract In this paper a two impinging streams cyclone contacting system suitable for handling of solid-liquid systems has been studied. Certain pertinent parameters such as: solid holdup, mean residence time and Residence Time Distribution (RTD) of solid particles have been investigated. A stochastic model based on Markov chains processes has been applied which describe the behavior of solid particles in the contacting system. From this model the RTD data were estimated and compared with the experimental results. The RTD data were obtained at different Dt and compared with those estimated from the model. At Dt = 0.362 s a good correlation has been observed between the predicted and experimental data. The RTD data may be used to determine certain pertinent characteristic parameters of physical and chemical apparatuses such as conversion in chemical reactors.