A liquid of 27 wt% acetone and 73 wt% water is to be separated at 25C into a raffinate and extract by multistage, countercurrent liquid– liquid extraction with a solvent of pure 1,1,2-trichloroethane. Equilibrium data are given in Exercise 8.11. Determine the:
(a) Minimum solvent-to-feed ratio to obtain a raffinate essentially free of acetone, 

(b) Composition of extract at the minimum solventto- feed ratio, 

(c) Composition of the extract stream leaving stage 2 (see Figure 8.13), if a very large number of equilibrium stages is used with the minimum solvent.

Data From Exercise 8.11 

One thousand kg/h of a 45 wt% acetone-in-water solution is to be extracted at 25^οC in a continuous, countercurrent system with pure 1,1,2-trichloroethane to obtain a raffinate containing 10 wt% acetone. Using the following equilibrium data, determine with an equilateral-triangle diagram: 

The tie-line data are:

Transcribed Image Text:

Extract E₁ F Feed R₁ R₂ R-1 R₂ RN-2 N-1 EN RN-1 Solvent S Raffinate RN Figure 8.13 Countercurrent-flow, N-equilibrium-stage liquid-liquid extraction cascade.