SIMULATION VIA ORTHOGONAL COLLOCATION ON FINITE-ELEMENT OF A CHROMATOGRAPHIC COLUMN WITH NONLINEAR ISOTHERM

The orthogonal collocation on finite element method is implemented for simulating a liquid chromatographic column. This procedure was retained from a comparative study of various numerical methods described in the first part of the paper. The modelling equations represent a general method for multicomponent systems, with linear or nonlinear equilibrium isotherms. The numerical procedure is illustrated in the second part by the simulation of single and binary systems. In the case of nonlinear isotherm the Langmuir isotherm is chosen. The numerical results show that the orthogonal collocation on finite elements is an efficient tool for solving liquid chromatography problems, even if high Peclet numbers are considered. When a non-competitive Langmuir isotherm is considered for the separation of binary systems, the retained numerical method reaches the convergence within low CPU times. For the case of competitive isotherm, the simulation of binary systems was carried out successfully but with larger CPU time. © 1991, Taylor & Francis Group, LLC. All rights reserved.