Design of batch chromatography for separation of binary mixtures under reduced purity requirements

Two methods are presented for designing separation of binary mixtures in a batch chromatography column under reduced purity requirements such that no waste or recycle fractions are generated. The first one is based on the equilibrium theory of chromatography and requires adsorption isotherm parameters. The second one is a shortcut method that uses a single experimental or simulated design chromatogram as input and is recommended under strongly non-ideal conditions with significant dispersive effects. Both approaches allow prediction of the injection volume and the cut position that lead to given target purities. In principle, they apply for all systems with convex or concave isotherms. The applicability of the design methods is evaluated by using numerical simulations. Both design methods work the better the higher the column efficiency and the lower the purity constraints are.