P$2$D$28(3$e$4$e$)$: Close to Ex$.2-4$ but horizontal with $3000$ lbmo$\frac{l}{h}$

A liquid mixture of $n-$hexane and $n-$octane is to be separated in a horizonta flash drum at $1$atm pressure. The feed flowrate is $B000$lbmo$\frac{l}{h}$ that is $40$mol$\%$ n$-$hexane and $60$mol$\%$ n$-$octane. We wish to produce a vapor that is $60$mol$\%n-$hexane. The bottom liquid product has $19$mol$\%n-$hexane, and $\frac{V}{F}=0\mathrm{.}51($by mole$).$ What size flash drum is required?

Data:

${}_L=0\mathrm{.}6960\frac{g}{m}l$

${}_V=0\mathrm{.}00314\frac{g}{m}l$

$M{W}_h=86\mathrm{.}17$

$M{W}_o=114\mathrm{.}22$

$K_{\text{d}\text{r}\text{u}\text{m}}=0\mathrm{.}5541$

$T_{\text{d}\text{r}\text{u}\text{m}}=378K$

Assume vapors are ideal gas.