In Problem 12.54, you calculated the CO₂ emission factor for several hydrocarbon fuels. Derive an expression for the CO₂ emission factor for an arbitrary hydrocarbon C_xH_y in which the hydrogen-to-carbon ratio y/x appears explicitly. Assume that all the fuel carbon appears in the products as CO₂ and use “simple” air. The atomic weights of C and H are 12.011 and 1.008, respectively. Use your expression to evaluate four of the same fuels as before:

i. Methane (CH₄)

ii. Propane (C₃H₈)

iii. Gasoline (C₈H₁₅-equivalent)iv. Diesel fuel (C₁₅H₂₂-equivalent)Plot the CO₂ emission factor as a function of the hydrogen-to-carbon ratio y/x.

Problem 12.54

Determine the mass of CO₂ produced (kg) per unit of energy released (kJ), i.e., the CO₂ emission, for the complete combustion of the following fuels. The higher heating value (HHV) expresses the energy released per mass of fuel burned.

Fuel Methane Natural gas Gasoline Diesel Ethanol Coal (Pbgh. #8) Hydrogen Composition CH4 C1.16H4.32 No.11 C7.9H14.8 C12.3H222 CH60 C65H52NSO3 H Higher heating value (kJ/kg) 55,528 50,000 47,300 44,800 29,700 32,550 142,000