Question

A processes that generates NO burns NH3 with oxygen fed with 20% excess

NH3 +O2 à NO +H2O

The reaction consumes 70% of the NH3. The NO is separated from the NH3 which didn’t react and is then recirculated to the feed.

a) Draw the flow diagram

b) Balance the chemical reaction

c) Find the moles of NO formed per 100 moles of NH3 fed.

d) Find the ratio of recirculated NH3 per formed mole of NO.

Answer 1

a)

As per the data provided

b)

Now the reaction given in the question

NH3 + O2 ------>NO +H20

Now we will balance the above reaction.

We will simply do the atomic species balance ( The number of atoms in LHS should match RHS)

NH3 + 2O2 ------>NO +(3/2)*H20

C) mols of 100 mols of NH3

Conversion of NH3 is 70 %

From reaction stoichiometry

1 nol NH3 = 1 mol NO

Mols of NH3 reacted = 0.7*100 = 70 mols

Mols of NO produced = 70 mols

d)

Mols of NH3 reacted = (1-0.7)*100 = 30 mols

As per the data provided in question, unreacted ammonia is reacted back

Hence, Ammonia recycled = 30 mol

mols of NO produced = 70 mols

Ratio of NH3 to NO produced = 30/70 =0.4286