Numerical Short-Cut Design of Simulated Moving Bed Chromatography for Multicomponent Nonlinear Adsorption Isotherms: Nonstoichiometric Langmuir Model

For the fine chemical
and pharmaceutical industries, simulated
moving bed (SMB) chromatography is a very promising separation process.
Because of its structural and operational complexity this periodically
operated multicolumn process is not easy to design and optimize. In
the 1990s, Storti, Mazzotti, and Morbidelli exploited the potential
of the equilibrium theory and developed a now well-established short-cut
design method for the conventional four-zone SMB processes. The concept,
which is known as the “triangle theory”, provides explicit
design rules for a small set of nonlinear adsorption isotherm models
and the case of processing binary feed mixtures. For the sake of extending
the triangle theory to multicomponent systems, we introduce in this
work a numerical short-cut method. The iterative method will be illustrated
to design a conventional four-zone SMB process for the separation
of quaternary mixtures obeying nonstoichiometric Langmuir isotherms.
The results will be validated by comparing predicted internal concentration
profiles with the results of additionally carried out true moving
bed simulations.