On the Number of Shocks in Chromatography

Displacement chromatography can be modelled mathematically by interacting Riemann problems for a system of conservation laws. The dependence of the number of shocks on the isotherms used to model the exchange process is investigated theoretically. For a particular separation process, the number of shocks predicted by the Langmuir isotherm and by a recently introduced non-ideal isotherm are compared with experiment. The conclusion is that the Langmuir isotherm predicts too few shocks.