Fractional crystallization provides a convenient means of purifying materials at low energy requirements and can be carried out continuously in a column crystallizer. This paper is concerned with the development of a model to describe the crystal forming cooling section of a column crystallizer used to separate a simple eutectic system. Experimentally determined crystal size distributions at various sections of the column obtained at different product to feed ratios are used to characterize the two parameters of a phenomenological model based on a dispersed plug flow configuration. The effects of hydrodynamic conditions on the model parameters are assessed in terms of dimensionless groups.