Solve Exercise 8.20 by the graphical method of Maloney and Schubert.

In Exercise 8.20:

A mixture containing 50 wt% methylcyclohexane (MCH) in n-heptane is fed to a countercurrent, stage-type extractor at 25°C. Aniline is used as solvent. Reflux is used on both ends of the column. An extract containing 95 wt% MCH and a raffinate containing 5 wt% MCH (both on solvent-free basis) are required. The minimum extract reflux ratio is 3.49. Using a right-triangle diagram with the equilibrium data of Exercise 8.22 below, calculate: (a) the raffinate reflux ratio, (b) the amount of aniline that must be removed at the separator "on top" of the column, and (c) the amount of solvent that must be added to the solvent mixer at the bottom of the column.