Exercise 1. An aqueous stream F of 0.11 kg/s comprises pyridine and water in equal weights. This stream should be purified in a countercurrent extraction process (see Figure 1). The concentration

of pyridine in the raffinate RN should be reduced to 5 wt% (or less). Pure benzene is to be used as solvent S. The ternary equilibrium diagram of water-pyridine-benzene is given in Figure 2. a) Calculate the minimum solvent stream, Smin b) The solvent stream Sis chosen to be 0.11 kg/s. Determine the value of flow E₁ c) d) Determine the number of equilibrium separation stages, N. Determine the size and composition of the extract leaving the second stage, E₂, 17 ke/s. (c) Nr. = 3, (d) X