In species exchange processes (e.g., ion-exchange chromatography column), conventional adsorption rate models describe mass transfer (or exchange) between phases, assuming the existence of a counterpart species. In contrast, the adsorption models may not be useful in an inert environment (or inactive zone) where adsorption/desorption cannot take place because of lack of counterpart species. In packed-bed chromatography described as a distributed dynamic system, a wide range of concentrations including zero-concentrations can be distributed over the column length and the concentration profiles move with time. Hence, the moving active and inactive zones are mixed over the column length. If a conventional adsorption rate model is employed in the inactive zone, computational solutions show that such a model can lead to unphysical negative concentrations. This study aims to develop a model such that conventional LDF (linear driving force) type models are extended to inactive zones without loosing their generality. Based on a limiting component constraint, an exchange probability kernel is developed for multi-component systems. The LDF-type model with the kernel is continuous with time and axial direction. Two tuning parameters such as concentration layer thickness and function change rate at the threshold point are needed for the probability kernels, which are not sensitive to problems considered.
|Publication status||Published - 2003|
|Event||13th European Symposium on Computer Aided Process Engineering: 36th European Symposium of the Working Party on Computer Aided Process Engineering - Lappeenranta, Finland|
Duration: 1 Jun 2003 → 4 Jun 2003
Conference number: 13, 36
|Conference||13th European Symposium on Computer Aided Process Engineering|
|Period||01/06/2003 → 04/06/2003|