One hundred kilogram-moles per hour of a saturated liquid mixture of 12 mol% ethyl alcohol in water is distilled continuously by direct steam at 1 atm introduced directly to the bottom plate. The distillate required is 85 mol% alcohol, representing 90% recovery of the alcohol in the feed. The reflux is saturated liquid with L/D = 3. Feed is on the optimal stage. Vapor-liquid equilibrium data are given in Exercise 7.29. Calculate:
(a) Steam requirement, kmol/h
(b) Number of theoretical stages
(c) The feed stage (optimal)
(d) Minimum reflux ratio,(L/D)min