Question

Q 1.

All these problems must be solved using Excel.

A natural gas consisting of methane is burned with an oxygen enriched air of composition 40% O2 and 60% N2, The Orsat analysis of the product gas as reported by the laboratory is CO2: 20.2%, O2: 4.1%, and N2 75.7%. Can this reported analysis be correct? Show the analysis.

Answer 1

The reaction is

CH4+2O2 --------àCO2+2H2O

Basis :100 moles of product

Product contain , CO2 =20.2, O2 =4.1 and N2=75.7

The source of N2 is enriched air containing 40%O2 and 60% N2.

Moles of air supplied =75.7/0.6 =126

Moles of oxygen present = 126*0.4= 50.4

From the reaction stoichiometry, moles of CH4 supplied= 20.2 moles

Moles of oxygen consumed = 2times moles of CH4= 2*20.2= 40.4 moles

Moles of oxygen remaining = 50.4-40.4= 10

But as per the products composition , only 4.1 moles of oxygen remains. But calculations suggest 10 moles of oxygen remaining. Hence the composition is incorrect.