A fuel $(100mo\frac{l}{h}r)$ is used to heat a process stream. The fuel enters the furnace at $30$ and $2$ bar and consists mainly of methane. The air enters the furnace at $25$ and $2$ bar. If the air is entered in excess

The flame temperation

What is the furnace efficiency if the stack temperature is $130C$

$C{H}_4+2O_{2}C{O}_2+2H_{2}O$

Required $O2=100*2=200$kmo$\frac{l}{h}r$

Entered $02=200**1\mathrm{.}2=240$kmo$\frac{l}{h}r$

Entered $N_2=240*(\frac{79}{21})=902\mathrm{.}85$kmo$\frac{l}{h}r$

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