A NEW MODEL FOR SOLVENT-EXTRACTION IN COLUMNS

A new model is proposed for analyzing solvent extraction processes carried out in any type of column. Each column is treated as a series of well-defined equilibrium stages where the backmixing (other-phase carryover) between stages can be large. It is assumed that mass transfer effects can be modeled by a proper choice for stage height and backmixing. With this model, the same number of stages can be used for all extracted chemical components no matter what their distribution coefficients. Thus, this model greatly simplifies the calculations required when evaluating multicomponent solvent extraction processes and so, is more appropriate than either the Height of an Eqivalent Theoretical Stage (HETS) or the Height of a Transfer Unit (HTU). Initial evaluation shows that the new model works as well as the HTU method and better than the HETS method when correlating actual pulse column data.