A total feed of 200 mol/h having an overall composition of 42 mol % heptane and 58 mol % ethyl benzene is to be fractionated at 101.3 kPa pressure to give a distillate containing 97 mol % heptane and a bottoms containing 1.1 mol % heptane. The feed enters the tower partially vaporized so that 40 mol % is liquid and 60 mol % is vapor. Equilibrium data are given. Calculate the following: A) Moles per hour distillate and bottoms.
B) Minimum reflux ratio Rm.
C) Minimum steps (theoretical trays) at total reflux.
D) Theoretical number of trays required for an operating reflux ratio of 2.2:1.
E) The composition of the streams entering and leaving stage 2 and the composition of the streams entering and leaving the last stage in the column.
Temperature
K oC xH yH K oC xH yH
409,3 136.1 0 0 383.8 110.6 0.485 0.730
402.6 129.4 0.08 0.230 376.0 102.8 0.790 0.904
392.6 119.4 0.250 0.514 371.5 98.3 1.000 1.000

A3-mm-thick panel of aluminum alloy (k 177 w/m-k, c 875 j/kg-k and ? = 2770 kg/m) is finished on both sides with an epoxy coating that must be cured at or above t,-150°c for at least 5 min. the production line for the curing operation involves two steps: (1) heating in a large oven with air at ts,0-175°c and a convection coefficient of h, 40 w/m2. k, and (2) cooling in a large chamber with air at 25°c and a con- vection coefficient of he 10 w/m2.k. the heating portion of the process is conducted over a time interval te which exceeds the ime required to reach 150°c by 5 min (h = r + 300 s). the coating has an emissivity of ? = 0.8, and the temperatures of the oven and chamber walls are 175 and 25°c, respectively. if the panel is placed in the oven at an initial temperature of 25°c and removed from the chamber at a safe-to-touch tempera ture of 37°c, what is the total elapsed time for the two-step curing operation?