$1)1\mathrm{.}25$kmol of $C_2{H}_4$ per kmol of $C{l}_2$ are fed to the reactor.Ethene and chlorine react to form dichloroethane via the main reaction $C_2{H}_4+C{l}_2{C}_2{H}_{4}C{l}_2$ and some of the ethene and chlorine also react to form tricholorethane via a side reaction $C_2{H}_4+2C{l}_2{C}_2{H}_{3}C{l}_3+HCl.$ However, a recycle for unreacted ethene is now being introduced. In this set up the byproducts leave with the dichloroethane. The single$-$pass conversion of chlorine is still $100\%$ and the selectivity of $C_2{H}_{4}C{l}_2$ over $C_2{H}_{3}C{l}_3$ is still $8.$ The plant is to be designed to produce $100,000$ te$/$y of dichloroethane and is to operate for $8000h$ per year.

a$)$Calculate the feed rates $(k\frac{g}{h})$ of ethene and chlorine required if $80\%$ of the unreacted ethene is recycled.

$2.$The separation stages from the process of Q$1$ are to be redesigned. Now, the $C_2{H}_{4}C{l}_2$ and the $C_2{H}_{3}C{l}_3$ are separated first in unit Sep #$1$ and leave as a mixed product stream $.$ All of the remaining gases, $C_2{H}_4,C{l}_2$ and $HCl,$ are recycled through an absorption unit $($Sep #$2),$ which allows for $100\%$ recyle of any unreacted ethene and selectively removes a fraction of the $HCl.$ The production rate of dichloroethane is to be maintained at $100,000$ te$/$y and the plant still operates for $8000\frac{h}{y}r.$ Calculate the steady$-$state flowrates of $HCl$ in the recycle before the absorber in $k\frac{g}{h},$ for the cases where

$($a$)$ All of the $HCl$ in the stream $<5>$ is removed in the Sep #$2$ absorber

$($b$)80\%$ of the $HCl$ in stream $<5>$ is removed in the Sep #$2$ absorber