Sugar extraction theory .1. Modelling via a constant effective diffusion coefficient

The effective extraction coefficient is defined as the product of the constant effective diffusion coefficient and the specific cossette surface. Comparison of this surface with the Silin number shows that the geometry of technical cossettes can be conceptualized as an infinitely long prism with a lateral ratio between 1:1 and 1:5. Continuous countercurrent extraction is characterized by theoretical separation stages and diffusion units. The Silin equation can be derived from the definition of the diffusion units. In view of the influence of axial dispersion, an efficiency rate is introduced, which mathematically can be unequivocally represented as a function of a parameter (quotient of the Peclet and Stanton numbers). The parameter is proportional to the square of the linear flow velocity and therefore correspondingly dependent on the fill rate.