5.1 Nicotine is removed from a water stream using kerosene. The inlet water solution of 200kg/h contains 2wt% nicotine. It is stripped with a kerosene stream of 500kg/h in a countercurrent stage tower. The equilibrium relationship between the kerosene layer (y) and the water layer (x) is y=x (where x is the mass fraction of nicotine in the water and y is that in kerosene). It is desired to remove 90% of the original nicotine in water stream. (a) Using a graph paper, plot the equilibrium line and operating line and determine the number of theoretical stages required. Attach the graph paper to the answer booklet for submission. (13 marks) (b) The solubility of nicotine in water is 16mg/ml and in ethanol is 50mg/ml. Explain whether ethanol could replace kerosene in the above extraction operation. (2 marks) 5.2 Mixer settlers are a class of equipment used in the solvent extraction process. Sketch the set-up of a mixer settler extractor