A fuel gas contains 80% propane (C 3 H 8 ) by mole and 20% butane (C 4 H 10 ) by mole. The fuel, mixed with a recycle stream is fed to a furnace, where conversions of 80% propane and 50% butane are...

1. A fuel gas contains 80% propane (C₃H₈) by mole and 20% butane (C₄H₁₀) by mole. The fuel, mixed with a recycle stream is fed to a furnace, where conversions of 80% propane and 50% butane are achieved. The fuel in the furnace is burned with 20% excess air via complete combustion. In the outlet of furnace all of the propane and butane is separated by a filter and this stream containing equimolar amounts of propane and butane is recycled to the reactor inlet. The remaining stack gas is released. The CO₂:O₂
   ratio in the stack gas is found to be 16.0:19.1.


2. Determine the composition of stack gas on wet basis.

Determine the ratio of fresh feed propane/recycled propane.