COMPARING STEADY COUNTERFLOW SEPARATION WITH DIFFERENTIAL CHROMATOGRAPHY

Separation of closely related solutes by steady solid-fluid counterflo w is compared with differential separation in a fixed chromatographic bed. Analogous expressions for exit concentration and mean residence t ime in the two systems are presented. A counterpart to chromatographic resolution is derived for binary steady counterflow separations. Esti mated counterflow savings in product-concentration dilution, solvent v olume requirement and solid-phase volume requirement obtained with the se expressions relative to comparable chromatographic operations are c ompared with experimental results from adsorptive, simulated moving be ds. Analysis of a size-exclusion protein separation suggests counterfl ow substantially decreases solvent and resin usage relative to convent ional, batch operation.