A mixture $(1$:$2$ on a molar basis$)$ of propane $($C$3$H$8)$ and butane $($C$4$H$10)$ is burned with excess pure oxygen in a continuous combustion chamber. The oxygen concentration in the combustion gases is measured and found to be $26\mathrm{.}47\%$ by volume. The combustion gases are then fed to a condenser which effectively removes all of the water vapour from the combustion gases to produce a dry gas stream containing only CO$2$ and any un$-$reacted O$2.$

a$.$ Assuming a basis of $100$ mol$/$h of C$3$H$8$ Prepare a carefully labelled PFD

indicating the known and unknown, mole fractions and flows for all process

streams. $[10\%]$

b$.$ Perform a Degrees of Freedom analysis for the overall process, and the subsystems associated with the combustion chamber and the condenser and

show that only the combustion chamber subsystem can be balanced. $[20\%]$

c$.$ Write down the two combustion reactions assuming that complete oxidation of

the hydrocarbons occurs and the only products of reaction are carbon dioxide

and water and hence determine the stoichiometric oxygen requirement for the

combustion reactions. $[10\%]$

d$.$ Determine all of the unknown flows and compositions for the process. $[30\%]$

e$.$ Express the composition and the flow rate of the dry product gas in mass

units.

$[20\%]$

f$.$ What would the composition of the gas from the condenser be if combustion

took place under stoichiometric oxygen conditions? $[10\%$