Project ForgeProcess Calculations
Material Balance
GATE 2018
Hard
Ammonia oxidation: 4NH3+5O2→6H2O+4NO. Air is supplied with O2 20% in excess of stoichiometric. The mole fraction of O2 in the inlet gas mixture (NH3+air) is (rounded off to third decimal place)
0.184(± 0.005 accepted)
Explanation
Stoichiometric O2 per mol NH3=5/4=1.25. With 20% excess: 1.5. Air (21% O2) supplying 1.5 mol O2 requires 1.5/0.21=7.143 mol air (with N2=5.643). Total gas=1(NH3)+7.143(air)=8.143. yO2=1.5/8.143=0.184.
Source: GATE CH 2018 (2018)
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