A common industrial application of batch distillation is the production of alcoholic beverages. The process starts by fermenting a batch of feedstock into an alcoholic broth, where organisms convert sugars and other molecules into ethanol. However, when the composition of ethanol in the broth reaches 12%, fermentation ceases because the organisms begin to die.

Since a composition of 40% ethanol is desired for many products, the broth must be batch-distilled to meet specifications. Starting with 400 mol of a 12% ethanol in water mixture, you aim to produce 80 mol of a 40% ethanol distillate product.

Your still has 5 stages (plus a reboiler). Find the reflux ratio that you should run to meet the specifications.

Note: As a special treat, you may make the following gross oversimplifications:

1)The compositions for alcoholic beverages are usually defined on a volume basis, you may simplify your calculations by taking all compositions given in this problem on a molar basis.

2)The equilibrium data of the system is well-described by a relative volatility of 3.