TRANSVERSE DISPERSION AND MALDISTRIBUTION IN A PULSED PERFORATED-PLATE EXTRACTION COLUMN

Transverse eddy diffusivities of dispersed phase drops in a 0.30-m dia meter pulsed perforated plate column were determined by two methods in volving measurement of changes in local holdup over the column half cr oss sections, one of which was initially drop free and the transfer of color tracer over the cross sections, in only one of which tracer was present initially. Both methods indicated a relatively low diffusivit y of similar to 10(-4) m(2) s(-1) for both emulsion and intermediate r egions of operation. However, similar tracer measurements of the radia l diffusivity for the continuous phase indicated virtually complete mi xing at the inlet stage. It is concluded that the reduced performance of these columns with increase in diameter in previous reports must ha ve been due to initial maldistribution at the dispersed phase distribu tor at low throughputs, and a proposal is made for a more suitable for m of distributor.