A gas turbine power plant receives a shipment of hydrocarbon fuel whose composition is uncertain but may be represented by the expression CxHy. The fuel is burned with excess air. An analysis of the product gas gives the following results on a moisture-free basis: 10.5 % (v/v) CO2, 5.3% O2, and 84.2% N2.

(a) Determine the molar ratio of hydrogen to carbon in the fuel (r), where r = y/x, and the percentage excess air used in the combustion.

(b) What is the air-to-fuel ratio (m3 air/kg of fuel) if the air is fed to the power plant at 30°C and 98 kPa?