OPTIMIZATION OF THE EXPERIMENTAL CONDITIONS AND THE COLUMN DESIGN PARAMETERS IN OVERLOADED ELUTION CHROMATOGRAPHY

A theoretical study of the optimization of the separation of a binary mixture in overloaded elution chromatography was performed. The elution band profiles were calculated using the semi-ideal model of chromatography and assuming competitive Langmuir isotherms. In a first step, the experimental (operating) conditions (i.e., the reduced velocity of the mobile phase and the loading factor) were optimized using a simplex algorithm. In a second step, the column design parameters (i.e., the column length and the average particle diameter) and the operating conditions were optimized for the maximum production rate of either the more or the less retained component. The optimum value of the capacity factor of the first component, was also determined. Binary mixtures having relative retentions between 1.1 and 1.8 and relative concentrations of 1:3 and 3:1 were studied. The maximum production rates were obtained for very low values of the capacity factor of the first component, of the order of 0.3-0.5, depending slightly on the relative retention.