Liquid extraction is used to isolate many pharmaceutical products. In liquid extraction of fermentation products, components dissolved in liquid are recovered by transfer into an appropriate solvent. In the isolation of penicillin, the drug is extracted from its aqueous broth using butyl acetate. This separation is carried out in a two-unit countercurrent design, as shown in Figure 3.28. 6 W, D, BA 5 W, D, BA 2 W, D, BA 3 D, BA 4 BA 1 W, D Liquid extraction I Liquid extraction II Figure 3.28 Two-unit countercurrent design for liquid extraction of penicillin. BA is butyl acetate; W is water; D is drug. of a dilute aqueous penicillin stream (stream 1) is extracted using butyl acetate in twounits. The inlet penicillin stream (stream 1) contains 0.50 wt% penicillin; the rest of the stream is water. The inlet butyl acetate mass flow rate (stream 4) is 30.0% of the inlet aqueous penicillin mass flow rate (stream 1). One outlet stream (stream 3) contains 3.0 wt% penicillin; the rest of the stream is butyl acetate. The other outlet flow (stream 6) contains water, penicillin, and butyl acetate. The mass fraction of penicillin in stream 6 is 1/4000 of the mass fraction of water in that stream. The separation of penicillin in the first stage is 98%; in other words, 98% of the penicillin mass entering Unit I is retained in stream 2. The compositions in stream 2 of penicillin and water are 1.7 wt% and 2.0 wt%, respectively. To solve this problem, an overall system encompassing both liquid extraction units must be drawn first. Solve for the required information in streams 1, 3, 4, and 6. Then, draw a system around Unit I and solve for the required information. You are encouraged to carry four or five significant figures for each number through this problem until you present the final answer. (a) Determine the total mass flow rate in each stream. (b) Determine the weight percents of butyl acetate, penicillin, and water, as appropriate, in each of the six streams.
3.15 Liquid extraction is used to isolate many pharmaceutical products. In liquid ex- traction of fermentation products, components dissolved in liquid are recov- ered by transfer into an appropriate solvent. In the isolation of penicillin, the is from its s broth using butyl acetate. This separation is carried out in a two-unit countercurrent design, as shown in Figure O BA O w, D, BA Liquid Liquid extraction D.BA extraction t countercurrent de. O w,D 20 W, D, BA liquid extraction of n. BA is butyl acetate; er; D is drug. 1.00 x 103 lbahr of a dilute aqueous penicillin stream (stream 1) is extracted using butyl acetate in twounits. The inlet penicillin stream (stream 1) contains 0.50 wt% penicillin; the rest of the stream is water. The inlet butyl acetate mass flow rate (stream 4) is 30.0% of the inlet aqueous penicillin mass flow rate (stream 1). One outlet stream (stream 3) contains 3.0 wt% penicillin; the rest of the stream is butyl acetate. The other outlet flow (stream 6) contains ter, penicillin, and butyl acetate. The mass fraction of penicillin in stream 6 is 1/4000 of the mass fraction of water in that stream. The separation peni cillin in the of en tering first stage is 98% n other words, 98% of the penicillin mass and Unit I is retained in stream 2. The compositions in stream 2 of penicillin water are 1.7 wt% and 2.0 wt%, respectively. tion To solve this problem, an overall system encompassing both liquid extrac 3, 4, units must be drawn first. Solve for the required information in streams 1 and 6. Then, draw a system around Unit l and solve for the required in