SAMPLE PROBLEM #5b:SAMPLE PROBLEM #5b:A feed containing 38 wt % acetone and 62 wt % A feed containing 38 wt % acetone and 62 wt % water is to be sent at 250 kg/hr to an extraction water is to be sent at 250 kg/hr to an extraction column to recover the acetone using 1,1,2-column to recover the acetone using 1,1,2-trichloroethane (C2H3Cl3) as the solvent. 85.5 trichloroethane (C2H3Cl3) as the solvent. 85.5 kg/hr of pure C2H3Cl3 is used as the solvent kg/hr of pure C2H3Cl3 is used as the solvent stream. We desire a raffinate product that stream. We desire a raffinate product that contains 8% acetone. Equilibrium data are given contains 8% acetone. Equilibrium data are given below. Solve this problem on a right-triangular below. Solve this problem on a right-triangular diagram.diagram.a. Plot the solubility envelope and the conjugate a. Plot the solubility envelope and the conjugate line for this system.line for this system.b. Find the exiting extract concentration and flow b. Find the exiting extract concentration and flow rate.rate.c. Find the number of equilibrium stages required c. Find the number of equilibrium stages required for this separation.for this separation.

Limiting solubility curveLimiting solubility curve

C2H3Cl3, wt % C2H3Cl3, wt % Water, wt % Water, wt % Acetone, wt % Acetone, wt %

94.73 94.73 0.26 0.26 5.01 5.01

79.58 79.58 0.76 0.76 19.66 19.66

67.5267.52 1.44 1.44 31.04 31.04

54.88 54.88 2.98 2.98 42.14 42.14

38.31 38.31 6.84 6.84 54.85 54.85

24.04 24.04 15.37 15.37 60.59 60.59

15.39 15.39 26.28 26.28 58.33 58.33

6.77 6.77 41.35 41.35 51.88 51.88

1.75 1.75 61.11 61.11 37.17 37.17

0.92 0.92 74.54 74.54 24.54 24.54

0.65 0.65 87.63 87.63 11.72 11.72

0.44 0.44 99.56 99.56 0.00 0.00

Tie LinesTie Lines

Wt % in Water Layer Wt % in Water Layer Wt % in Tricholoethane Wt % in Tricholoethane Layer Layer

CC22HH33ClCl3 3 Water Water AcetoneAcetone

0.52 0.52 93.52 93.52 5.96 5.96

0.73 0.73 82.23 82.23 17.04 17.04

1.02 1.02 72.06 72.06 26.92 26.92

1.17 1.17 67.95 67.95 30.88 30.88

1.60 1.60 62.67 62.67 35.73 35.73

2.10 2.10 57.00 57.00 40.90 40.90

3.75 3.75 50.20 50.20 46.05 46.05

6.52 6.52 41.70 41.70 51.78 51.78

CC22HH33ClCl33 Water Water Acetone Acetone

90.93 90.93 0.32 0.32 8.75 8.75

73.76 73.76 1.10 1.10 25.14 25.14

59.21 59.21 2.27 2.27 38.52 38.52

53.92 53.92 3.11 3.11 42.97 42.97

47.53 47.53 4.26 4.26 48.21 48.21

40.00 40.00 6.05 6.05 53.95 53.95

33.70 33.70 8.90 8.90 57.40 57.40

26.26 26.26 13.40 13.40 60.34 60.34

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V1

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number of stages = 5.5 ≈

6

V1 compositionV1 composition:: 47% acetone47% acetone

OMB: 250 + 85.5 = E + ROMB: 250 + 85.5 = E + RAcetone balance: 0.38(250) = 0.47E + 0.08RAcetone balance: 0.38(250) = 0.47E + 0.08RSolving: E = 174.8 kgSolving: E = 174.8 kg