A flash drum is to flash \(10,000 \mathrm{lbmol} / \mathrm{h}\) of a feed that is \(65 \mathrm{~mol} \% \mathrm{n}\)-hexane and \(35 \mathrm{~mol} \% \mathrm{n}-o c t a n e\) at \(1.0 \mathrm{~atm}\) pressure. \(\mathrm{V} / \mathrm{F}=0.4\).

a. Find \(\mathrm{T}_{\text {drum }}\), liquid mole fraction, and vapor mole fraction.

b. Find the size required for a vertical flash drum.

Values of y, x, and T at equilibrium can be determined from the DePriester charts. Other required physical property data are given in Example 2-4.

Example 2-4 

A vertical flash drum is to flash a liquid feed of 1500 lbmol/h that is 40 mol% n-hexane and 60 mol% n-octane at 101.3 kPa (1 atm). We wish to produce a vapor that is 60 mol% n-hexane. Solution of the flash equations with equilibrium data for y_H = 0.60 gives x_H = 0.19, T_drum = 378K, and V/F = 0.51. What size flash drum is required?