QUESTION $2$

An effluent gas from a refinery with composition $C{H}_4,C_2{H}_6,C_3{H}_8$ and $C_4{H}_{10}$ is fed into an absorber to reduce the propane content of the effluent before recycling. The absorber operated at $37C$ and $400$ kPa $($abs$).$ The entering oil and gas with its composition is shown in the following table. The absorber has $4$ theoretical stages.

Table $1$: The entering oil and gas with its composition

$\backslash$table$[[,L{o}_0,$kmo$\frac{l}{h},V_{N+1},$kmo$\frac{l}{h},K_i$