Question

Ammonia is burned to form nitric oxide in the following reaction: 4NH₃ + 5O₂ ----> 4NO + 6H₂O

The Fractional conversion of oxygen is 0.500 and the inlet flow rates of NH₃ is 10 mol/h

Oxygen is supplied using air (assume 79:21 - N₂:O₂) fed to reactor at rate of 710 g/h

(a) How much oxygen is fed to the reactor (in mol/h)?

(b) Which reactan is in excess and by how much (in %)?

(c) Calculate the exit molar flow rates of all compounds (in mol/h)

Answer 1

(a)

The air has average molar mass of 29 g/mol.

Air is fed to reactor at rate of 710 g/h. This corresponds to

Assume 79:21 - N2:O2

Hence O2 is fed to reactor at rate of

(b)

The flow rates of ammonia and O2 are 10 mol/h and 5.14 mol/h respectively.

10 mol/h ammonia will react with O2 however only 5.14 mol/h O2 is present. Hence, O2 is the limiting reactant and NH3 is excess reactant.

% Excess of %

(c) The Fractional conversion of oxygen is 0.500. So the exit molar flow rate of

The exit molar flow rate of NO

The exit molar flow rate of

The exit molar flow rate of