COMPARISON OF THE RESULTS OBTAINED WITH DIFFERENT MODELS FOR THE SIMULATION OF PREPARATIVE CHROMATOGRAPHY

We examine the theoretical similarities and differences between three calculation procedures used for the simulation of band propagation in non-linear chromatography. All three approaches are implementations of the finite difference method of integration of the partial differential equations which state the mass balances of the sample components. The elution profiles calculated with these three procedures agree quite well when applied to reasonably efficient columns (over 1000 theoretical plates), at moderate and high sample loads as long as the displacement effect predominates. These profiles also agree well with experimental results. Significant differences appear, however, when the concentration of the second component in the feed is smaller than that of the first one. The origin and extent of these differences are discussed in detail and the range of deviations to be expected in practical cases is illustrated.