Forced Periodic Non-isothermal Operation of Chromatographic Columns

Chromatography is a powerful and very selective separation and purification process exploiting specific interactions of the compounds to be separated with dedicated adsorbents. A high purity and a high yield at reasonable production rate are the main demands of scientists working in this area. Typically isothermal conditions are applied, although potential was seen already in non-isothermal operation. The temperature fluctuations were found to be partly helpful in the case of gas phase separations. However, such effects have been neglected in the liquid phase chromatography. This project focuses on optimizing the separation of two components of a liquid mixture whose concentrations are effected by the interaction and reaction with the solid phase packed inside the column. We impose a non-isothermal condition by controlling temperature variations in the column in such a way that a preceding component of the mixture is warmed up to leave the column more quickly as compared to the succeeding component which is cooled down and, thus, migrates slower. The basic model, which we will consider in the beginning, is called as equilibrium dispersive model (EDM). It incorporates the well-known mass balance equation of a column coupled with the energy balance and specific initial and boundary conditions. The aim of this project is to provide theoretical understanding of the said setup, to resolve sharp discontinuities in the absence of axial dispersion by using Riemann Problems approach, to analyze the effects of temperature fluctuations on the process, and to approximate the full nonlinear model by using a high resolution finite volume scheme. Experimental tests will be done later on in collaboration with scientists in MPI Magdeburg, who are working on experimental chromatographic processes.