A natural gas stream having the following molar composition:

$\backslash$table$[[$Substance$,$Mole$\%,$Substance,Mole $\%],[C_4{H}_{10},11,C_2{H}_4,6],[C_3{H}_8,14,C{H}_4,56],[C_2{H}_6,9,N_2,4]]$

is burnt with air in the reformer of a DRI plant at the rate of $520m^3{h}^{-1}$ measured at $3\mathrm{.}5$atm and $27C.$ Fifteen per cent $(15\%)$ excess air is used in the reformer and the resulting flue gas has a $C{O}_2$ to $CO$ ratio of $20$ to $1.$ If the air enters at $1$atm and $27C,$ calculate

$($i$)$ the flow rate of inlet air in $m^3{h}^{-1}..$

$(10$ Marks$)$

$($ii$)$ the Orsat $($i$.$e$.$ on a dry basis$)$ analysis of the flue gas.

$(15$ Marks$)$

Assume air consists of $79$mole$\%$ nitrogen and $21$ mole$\%$ oxygen. Also assume that there is no hydrocarbon in the flue gas and consider CAREFULLY the species which will make up the flue gas.

$R=0\mathrm{.}08206m^3$ atm $kmo{l}^{-1}{K}^{-1}$

Final $2022$