Where the oxygen comes from the air (21% o2 and 79% n2). if oxygen is fed from air in excess of the stoichiometric amount required to combust all of the ethanol by 10%, and 85% of the ethanol reacts, calculate the mole fraction of oxygen leaving the reactor.

%

Explanation:

The ethanol combustion reaction is:

→

If we had the amount (x moles) of ethanol, we would calculate the oxygen moles required:

Dividing the previous equation by x:

We would need 3.30 oxygen moles per ethanol mole.

Then we apply the composition relation between O2 and N2 in the feed air:

Then calculate the oxygen moles number leaving the reactor, considering that 0.85 ethanol moles react and the stoichiometry of the reaction:

Calculate the number of moles of CO2 and water considering the same:

The total number of moles at the reactor output would be:

So, the oxygen mole fraction would be:

%

6.4 cm (max) - 25 cm (min)