$(35pt)$ Methane gas $($CH$4)$ enters a heat treatment furnace operating in steady state at $25C$ and $1$atm

pressure and reacts with $140\%$ theoretical air of the same temperature and pressure. Combustion

products come out at $1$atm pressure and $427C$ temperature. Determine;

a$)(8pt)$ The balanced reaction equation for $1$kmol of $CH4.$

b$)(7$ pt$)$ Air fuel ratio, at molar and mass base $($Kmol$-$air$/$Kmol$-$Methane and kg$-$air$/$kg$-$methane$)$

c$)(20pt)$ Heat transfer amount for this reaction, in $k\frac{J}{k}$mol$-CH4.$

$(30pt)$ Ethane $(C2H6)$ enters a reactor shown in the figure at a temperature of $25C$ and a pressure of

$100$kPa; It burns completely with $100\%$ of theoretical air at the same temperature and pressure.

Combustion products leaves the reactor at $627C,$ and $1066M\frac{J}{k}$mol$-$ethane heat transfer occurs from

the reactor to the environment at a surface temperature of $327C.$ Determine;

a$)(5$ pt$)$ The balanced reaction

equation for $1$kmol of $C2H6.$

b$)(5$ pt$)$ Molar ratio of $H2O$ at

combustion products.

c$)(20pt)$ Entropy generation

for $1$kmol of $C2H6,$ in

$k\frac{J}{k}$mol$-$ethane $*K$

a$)(20$ p$)$ Describe Flame types by drawing and samples.

b$)(20p)$ Explain $($ NOx $)$ formation during the combustion reactions.