Chapter 5, Problem 5.51P

A gas turbine power plant receives a shipment of hydrocarbon fuel whose composition is uncertain but may be represented by the expression ${\text{C}}_x{\text{H}}_y$. The fuel is burned with excess air. An analysis of the product gas gives the following results on a moisture-free basis: $10.5\%\left(\text{v/v}\right){\text{CO}}_{\text{2}}\text{,}\text{5}\text{.3\%}{\text{O}}_{\text{2}}$, and $84.2{\text{N}}_2$.

(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 (m³air/kg of fuel) if the air is fed to the power plant at 30°C and 98 kPa?

(c) The speci?c gravity of the fuel (a petroleum product) is 0.85. Estimate the ratio standard cubic feet of gas fed to the turbine per barrel of fuel.

Exploratory Exercise—Research and Discover (d) What are the issues associated with using oil as a fuel as opposed to natural gas‘? Consider two factors: (i) the complete composition of typical fuel oils and their resulting emissions, and (ii) the availability and global distribution of the two fuel sources.