Axial dispersion coefficients have been measured in the continuous phase of a 10.8 cm diameter pulsed plate extraction column. The measurements were made by observing the course of an instantaneous chemical reaction between acid and base in the continuous phase, using phenolphthalein as an indicator.
Two different plates were employed, namely perforated and star-shaped plates. The air pulsing was generated by means of solenoid valves and a timing controller. The pulsation amplitude and frequency were varied from 0.5 to 8.0 cm and from 0.5 to 2.0 Hz, respectively.
Axial dispersion increased proportionally with the product of the square of amplitude and frequency, however, it decreased with free opening area of the plate and plate spacing. The flow rates of each phase and the plate thickness have insignificant effects on the axial dispersion.
The data have been correlated in terms of amplitude, frequency, plate spacing and free opening area of the plates.