DISPERSED-PHASE RESIDENCE TIMES IN A WIRZ EXTRACTION COLUMN

Residence-time distribution of the dispersed phase has been investigat ed in a 150-mm-diameter Wirz-II agitated extraction column for six dif ferent liquid-liquid systems of medium to low interfacial tension and small density difference, using a two-point transient tracer technique . The flow of the dispersed phase is described by a convective model, and drop velocities and constriction factors are calculated from measu red residence-time curves and drop-size distributions. For design purp oses, an empirical correlation is presented for the average constricti on factor in terms of the agitator speed and density difference betwee n the phases.