It is required to design a fractionation tower to operate at 101.3 kPa to obtain a distillate consisting of 95 mol% acetone (A) and 5 mol% water, and a residue containing 1 mol% A. The liquid is at 125?C and 687 kPa and contains 57 mol% A. The feed is introduced to the column through an expansion valve so that it enters the column partially vaporized at 60oC. From the data below, determine the molar ratio of liquid to vapor in the partially vaporized feed. Enthalpy and equilibrium data are as follows:

Molar latent heat of A = 29,750 kJ/kmol (constant)

Molar latent heat of H2O = 42,430 kJ/kmol (constant)

Molar specific heat of A = 134 kJ/kmol - K (constant)

Molar specific heat of H2O = 75.3 kJ/kmol-K (constant)

Enthalpy of high-pressure, hot feed before adiabatic expansion = 0

Enthalpies of feed phases after expansion: hv = 27,200 kJ/kmol, hL = -5,270kJ/kmo1

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VAPOR-LIQUID EQUILIBRIUM DATA FOR ACETONE-HO AT 101.3 kPA T, "C 56.7 57.1 60.0 610 63.0 71.7 100 Mol A in liquid: 100 92.0 50.0 33.0 17.6 6.8 Mol% A 85.0 837 80.5 69.2 in vapor: 100 94,4