4. A single stage liquid-liquid extraction process is being used to recover antibiotic Penicillin F from dilute aqueous fermentation broth containing 0.6 wt% Penicillin F using pure solvent amyl acetate. The ratio of solvent mass flow rate to feed mass flow rate is 0.1. The equilibrium relation is y = 85x, where y and x are the mass fraction of Penicillin F in the extract and raffinate phase, respectively at equilibrium. Assume that the solvent amyl acetate is insoluble in water. a) What are the compositions of the exit extract and raffinate streams? Hint: Write a mass balance and the equilibrium relationship. b) What percent of Penicillin F is recovered in the extract? c) You design a multistage liquid-liquid extraction process to increase the recovery of Penicillin F. How many stages are required to achieve 99% recovery? Note: When the solvent and carrier liquid are immiscible, the equations that describe liquid-liquid extraction are the same as those for absorption and stripping! This is a dilute system which allows you to make some simplifications. Also, for dilute systems the Kremser equation is valid.