ABSTRACT
Many processes in Chemical Engineering involve matter exchange between two phases in view of separate or analyze multicomponent mixtures. One can mention chromatography [5], [3], distillation [1], or electrophoresis. It is possible, under several hypothesis, to model these processes by a system of first order conservation laws. Consider a 1-dimensional diphasic medium in which phase 1 is moving with a velocity u, and phase 2 with velocity v. Assume u and v to be constant, u > 0 and v ≤ 0: we deal with a countercurrent process. We shall assume also that the whole process is isothermal. Thus the equations of momentum and energy are useless, and we are left with the conservation of matter. So, let c1 and c2 be vector-valued functions of x and t, related to the concentrations in phase 1 and 2 respectively. We have https://www.w3.org/1998/Math/MathML"> ∂ t c 1 + c 2 + ∂ x u c 1 + v c 2 = 0. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003062240/a6b2dc90-37e3-4130-a669-09768d846a56/content/eqn1_1d.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
