Single liquid drop breakage probabilities and characteristic velocities in Kühni columns

Abstract

AbstractStudies have been made on the extent and mechanism of breakage of single liquid drops of organic liquids immiscible in water rising through short sections of Kühni liquid‐liquid extraction columns. Information on drop breakage probabilities is required for calculation of drop size distributions developed under counter‐current column operating conditions. The breakage probability data from two small diameter Kühni columns containing one, three or five stages have been correlated as a function of a modified Weber number based on the shearing forces on drops. The critical condition for breakage, giving a maximum stable drop size, is based on an impeller Weber number. Characteristic velocities of drops were measured relative to terminal velocity and the ratio was tentatively correlated with a function of an impeller Reynolds number together with the fractional free area of the perforated plates used to separate compartments. The drops were found to break predominantly at the holes in the plates, not at the turbine, in the region of transitional Reynolds number used in this work. The results apply only to non‐turbulent conditions so further work on larger diameter equipment is called for.