Longitudinal dispersion of the continuous phase was studied in spray extrac
tors operated in the loose, close, and turbulized drop packing modes. The P
eclet number was found to depend on the Reynolds number modified to take in
to account the hydrodynamic conditions in the working zone of the column. W
hen the continuous phase is pulsed, the Peclet number is also governed by t
he modified Reynolds number, which accounts for the effect of pulsation on
the longitudinal dispersion.