Analysis of the three-step cyclic process of countercurrent extraction

A mathematical model of the three-step cyclic process of countercurrent extraction has been developed. Each cycle consists of two half periods, i.e., the half period of the motion of the flow of the first solvent phase and the half period of the motion of the flow of the second solvent phase. The first half period is composed of two steps, i.e., the step of feed supply (first solvent containing an initial mixture of components) and the step of the supply of the first solvent (without the initial mixture). The analytical dependences that describe the concentration profiles in a cascade of equilibrium stages at all three steps of the process for each cycle and a change in the concentrations in the output flows of the raffinate and extract phases were obtained. An analysis of the influence of operating parameters on the efficiency of the process of separation of a binary mixture was performed.