CHROMDIFF - Dispersion Model for Chromatography Columns

13 CHROMDIFF - Dispersion Rate Model for Chromatography Columns 

As explained in Sec. 4.4.4, the movement of components through a chromatography column can be modelled by a two-phase rate model, which is able to handle multicomponents with nonlinear equilibria. In Fig. 1 the column with segment n is shown, and in Fig. 2 the structure of the model is depicted. This involves the writing of separate liquid and solid phase component balance equations, for each segment n of the column. The movement of the solute components through the column occurs by both convective flow and axial dispersion within the liquid phase and by solute mass transfer from the liquid phase to the solid. 

The equations have previously been derived in Sec. 4.4.4 in a form suitable for programming with Madonna. Correlations for the column Peclet number are taken from the literature and used to calculate a suitable value for the dispersion coefficient, for use in the model. 

The model is written in vector form with the last elements taken separately to satisfy the closed end boundary conditions. 

Study the influence of the equilibrium constant ratio Kb/Ka, for the two components A and B, on the resolution of the peaks, as given by the time difference between the peaks. 

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