The coal gas is to be freed of its light oil by scrubbing

with wash oil as an absorbent and $($B$)$ the light oil

recovered by stripping the resulting solution with steam,

The benzene free light oil circulation rate from absorber

is $1\mathrm{.}987{10}^{-3}\frac{\text{k}\text{m}\text{o}\text{l}}{sec}$ and with a mole ratio of

$0\mathrm{.}119$ kmol benzene$/$ kmol oil. The solution at $120C$ enters

the stripper at $1$atm pressure. Stripping pure steam

at standard atmosphere and superheated to $122C$ is used

for stripping operation. The debenzolized oil, $0\mathrm{.}005$ mole

fraction benzene, is to be cooled to $26C$ and returned

to the absorber$.$ A steam rate of $1\mathrm{.}5$ times the minimum is

to be used. The temperature will be constant at $122C.$

Vapor pressure of benzene is $2400mmHg(319\mathrm{.}9\frac{kN}{m^2})$

Compute the steam rate required and number of theoretical

stages.