26.4-4. Minimum Number of Theoretical Plates and Minimum Reflux Ratio. Determine the minimum reflux ratio Rm and the minimum number of theoretical plates at total reflux for the rectification of a mixture of heptane and ethyl benzene as given in Problem 26.4-2. Do this by using the graphical methods of McCabe-Thiele. trays plus reboiler 26.4-2. Rectification of a Heptane-Ethyl Benzene Mixture. A saturated liquid feed of 200 mol/h at the boiling point containing 42 mol % heptane and 58% ethyl benzene is to be fractionated at 101.32 kPa abs to give a distillate containing 97 mol % hep- tane and a bottoms containing 1.1 mol % heptane. The reflux ratio used is 2.5:1. Calculate the mol/h distillate, mol/h bottoms, theoretical number of trays, and the feed tray number. Equilibrium data are given below at 101.32 kPa abs pressure for the mole fraction n-heptane xy and yh: Temperature Temperature K C X K C XH 409.3 402.6 0 136.1 129.4 0.730 0 0.08 0.250 383.8 376.0 371.5 0.230 0.514 110.6 102.8 98.3 0.485 0.790 1.000 0.904 392.6 119.4 1.000