9.13 Use the Fenske-Underwood-Gilliland shortcut method to determine the reflux ratio required to conduct the distillation operation indicated in Figure 9.25 if N/Nmin = 2.0, the average relative volatility = 1.11, and the feed is at the bubble-point temperature at column feed-stage pressure. partial reboiler. Assume a total condenser and a Distillate kmol/h Feed Propylene 347.5 Distillation Propane kmol/h 3.5 351.0 Propylene Propane 360 240 Bottoms 600 Figure 9.25 Data for Exercise 9.13.