Performance of an internally baffled multistage extraction column



Internally agitated extraction columns generally require increasing heights for a theoretical state for the larger column diameters. The present work describes a design developed to minimize this objection and presents the performance data on a system considered easy to extract and on systems considered difficult to extract. H.E.T.S. values as low as 3 in. on the first system and 4 in. on the second type of system were obtained in an 11½ in I.D. glass column. The stage efficiencies were correlated as a function of power input per unit volume of solvent throughput and the ratio of the flow rate of the dispersed phase to that of the continous phases. The supplementary effect of packing was studied and found to be most beneficial in the system which has a low interfacial tension and is considered easy to extract. By the use of this particular arrangement of internal baffles, it is believed possible, in the larger diameter columns, to reduce the height to a ratio of H.E.T.S. to diameter below the value of ¼ obtained in the present column.