Dilute countercurrent immiscible extraction A feed of 100.0 kg/min of a 1.2 wt % mixture of acetic acid in water is to be extracted with 1-butanol at 1 atm pressure and 26.7°C, we desire an outlet concentration of 0.1 wt % acetic acid in the exiting water. We have available solvent stream 1 that is 44.0 kg/min of pure 1-butanol and solvent stream 2 that is 30.0 kg/min of 1-butanol that contains 0.4 wt % acetic acid. Devise a scheme to do this separation, find the outlet flow rate and concentration of the exiting 1-butanol phase, and find the number of equilibrium contacts needed.
In Example we assumed that we were going to use all of the solvent available. There are other alternatives. Determine if the following alternatives are capable of producing outlet water of the desired acetic acid concentration.
a. Use only the pure solvent at the bottom of the extractor.
b. Mix all of the pure and all of the impure solvent together and use them at the bottom of the column.
c. Mix all of the pure and part of the impure solvent together and use them at the bottom of the column.