Methane $($CH $)$ at $298$ K$,1$ atm enters a furnace operating at steady state and burns completely with $220\%$ of theoretical air entering at $400$ K$,1$ atm. The products of combustion exit at $500$ K$,1$ atm. The ow rate of the methane is $1\mathrm{.}2$ kg$/$min$.$ Kinetic and potential energy effects are negligible and air can be modeled as $21\%$ O and $79\%$ N on a molar basis.