ISBN 978-3-8439-2984-4

978-3-8439-2984-4, Reihe Verfahrenstechnik

Kiara Kochendörfer
Chromatographic Purification of an Intermediately Eluting Component from a Complex Mixture

167 Seiten, Dissertation Universität Erlangen-Nürnberg (2016), Softcover, A5

Zusammenfassung / Abstract

This work deals with the development of systematic guidelines for the design of a 4-zone Simulated Moving Bed (SMB) purification of an intermediately eluting component from a complex mixture. The objective of the purification is the separation of the target component from a critical impurity, achieving high recovery of the target component and meeting the purity specifications with respect to the product sensory properties.

The process design strategy proposed in this work includes the following steps: (1) the separation task is simplified to the separation of a binary mixture; (2) this mixture is used for screening and preselection of stationary and mobile phases by performing pulse injection experiments; (3) the mobile phase composition is fine-tuned using the complex mixture; (4) preliminary SMB experiments are performed with the simplified binary mixture using SMB operating parameters selected by the equilibrium theory; (5) the SMB binary separation is modeled and simulated using experimentally determined model parameters; (6) SMB experiments performed with the real complex mixture are used to validate the model; (7) a model-based optimization with respect to purity, recovery, throughput and solvent consumption is conducted; (8) the optimized SMB unit operating parameters are validated experimentally.

The equilibrium theory can only be used to select operating parameters of SMB units for the separation of a target component from a multicomponent mixture when the target component is either first or last eluting. The purification of the much earlier and later eluting components than the critical impurity and the target component are mainly governed by the operating points in the mI/mIV plane. Due to the large number of components present in the complex mixture and their widely varying adsorption behavior, complete regeneration of stationary and mobile phase is impractical. Moreover, the presence of non-critical impurities between the target component and the critical impurity results in a trade-off between recovery and purity of the target component. Using the validated SMB model, two sets of isolines in the mII/mIII plane, one for purity and one for recovery were derived. For a given pair of minimal purity and recovery specifications, the corresponding isolines enclose a triangular region of feasible SMB unit operating points, where the vertex corresponds to the maximum throughput (analogously to classical triangle theory for binary separations).