Simulation of Fixed-Bed Chromatographic Processes Considering the Nonlinear Adsorption Isotherms.

Area of Science:

• Chemical Engineering
• Computational Chemistry
• Separation Science

Background:

• Chromatographic processes are vital for separating mixtures.
• Modeling multicomponent mixtures requires advanced techniques due to complex interactions.
• Existing models often struggle with the advection-diffusion dynamics in fixed beds.

Purpose of the Study:

• To numerically approximate a nonlinear equilibrium-dispersive (ED) model for multicomponent mixtures.
• To apply the Runge-Kutta discontinuous Galerkin (RKDG) finite element method to solve advection-diffusion equations in chromatography.
• To validate the RKDG method against a high-resolution finite volume scheme for various chromatographic scenarios.

Main Methods:

• Numerical approximation of a nonlinear equilibrium-dispersive (ED) model.
• Application of Danckwerts boundary conditions (DBCs) for generalized and standard bi-Langmuir isotherms.
• Implementation of the Runge-Kutta discontinuous Galerkin (RKDG) finite element method.
• Comparison with a high-resolution finite volume scheme.

Main Results:

• The RKDG method successfully handles sharp discontinuities in solutions.
• Highly accurate numerical results were obtained for one-, two-, and three-component liquid chromatography elutions.
• The RKDG method demonstrated comparable or superior accuracy to the finite volume scheme.

Conclusions:

• The RKDG finite element method is a robust and accurate technique for simulating multicomponent chromatographic processes.
• This dynamic model provides a foundation for continuous monitoring and control of chromatography.
• The study advances the simulation capabilities for complex separation processes.