In a continuous countercurrent train of mixer-settlers, 100 kg/h of a 40:60 acetone-water solution is to be reduced to 10 percent acetone by extraction with pure 1.1.2-trichloroethane at 25°C. 

(a) Find the minimum solvent rate. 

(b) At 1.8 times the minimum (solvent rate)/(feed rate), find the number of stages required. 

(c) For conditions of part (b) find the mass flow rates of all streams. Data are given in Table 23.6.

Table 23.6

Transcribed Image Text:

TABLE 23.6 Equilibrium data C,H,CI,, wt 94.73 79.58 67.52 54.88 38.31 24.04 15.39 6.77 1.72 0.92 0.65 0.44 CH₂CI, 0.52 0.73 1.02 1.17 1.60 2.10 3.75 6.52 Weight % in water layer Water 93.52 82.23 72.06 67.95 Limiting solubility curve Water, wt% 62.67 57.00 50.20 41.70 40.90 46.05 51.78 0.26 0.76 1.44 2.98 6.84 15.37 26.28 41.35 61.11 74.54 Acetone 5.96 17.04 26.92 30,88 35.73 87.63 99.56 Tie lines C,H,CI, 90.93 73.76 59.21 53.92 47.53 40.00 33.70 26.26 Weight % in trichloroethane layer Acetone, wt% 5.01 19.66 31.04 42,14 54.35 60.39 58.33 51.88 37.17 24.54 11.72 6.00 Water 0.32 1.10 2.27 3.11 6.05 8.90 13.40 Acetone 8.75 25.14 38 52 42.97 4821 53.95 57.40 60.34