Problem $3[40$ points$]$

A natural gas containing $82$ mole $\%$ methane and rest ethane is burned in $20\%$ exers air in a furnax.

The fuel gas enters at $350K$ and the air is preheated to $423K.$ The $C_p$ values of the stark components

can be considered to be constant, with the values

At strady state

$($a$)$ Compute the adiahatic flame temperature for this combustion

$($b$)$ Will the temperature of the flue gas $($gases exiting the furnace$)$ be greater or analler than this

value in reality? Why?

$($c$)$ How would the flame tenperature change with increase in excess air? How does increasing

concentration of methane in the fuel change it it$?$

Assume all reactions to occur at $1$ atm pressure. Additional values required for calculations $($if

any$)$ can be found in Table B$.1$ of Felder and Rousesan. Check footnoles of the table for units

and stale of combustion products.