Unified Design of chromatographic processes with timed events: Separation of ternary mixtures

An important unifying property of single and multicolumn chromatographic processes, whether discontinuous or continuous, is that they are based on timed events. The Unified Design method was revised by defining three kinds of events (cut event, fixed-bed event, SMB event). Binary and multicomponent separations in various process configurations, from single column batch to complex multicolumn units, can readily be described as combinations of such events. New dimensionless parameters were introduced to describe these events, and their combinations were used as operating parameters for different processes. Transformations between physical and dimensionless operating parameters were introduced. Regions of feasible operating parameters for complete separation of ternary mixtures with linear isotherms were derived for batch chromatography and two SMB-type processes (Japan Organo, 3W−ISMB) using the equilibrium theory. It was shown that these can be visualized and overlaid on the Unified Design operating parameter plane, which enables their direct comparison. It was found that in many cases the complete separation regions of apparently very different process schemes are identical or exhibit strong similarities. This indicates that it should be possible to transfer the operating point from one process mode to another without affecting the product purity if column efficiency is very high.