How to calculate the real air excess and the exhaust gases flow using indirect method?

This is avery commom problem in the combustion process whatsoever system is used(engines, turbines, boilers, etc...).

In the real field test the follwoing items are known:

1.-fuel composition(main components)
2.-exhaust gas composition(main components) by one standard analysing equipment relative low price and good quality in the market.
3.-Stechiometry relationships

With the values mentioned above one iterative process can be prepared with the follwing steps:

(a)fuel composition
m(excess air): (suppossed to be iterated)

consider 100 units of cble

vCH4:known by fuel analysis
vC2H6:" "
vC3H8:" "
vH2: " "
vN2: " "
vCO: " "

(b)stechiometry relations
CO2->CO2
CO+1/2O2->CO2
CH4+2O2->CO2+2H2O
CH4+3/2O2->CO+2H2O
N2->N2
N2+O2->2NO
C2H6+7/2O2->2CO2+3H2O
C3H8+5O2->3CO2+4H2O
H2+1/2O2->H2O

(c)exhaust gas analysis

vO2hs: with analysis equipment
vCOhs:" "
vNOxhs:" "


(d)calculations

Exhaust flow --> vhs:vCO2hs+vN2hs+VO2hs+vCOhs+vNOxhs

vCO2h:by stechiometrical relations (from above)
vN2hs:" "
vO2hs:" "
vH2Oh:" "

(e)iterative process( 2 to 4 iterations ok if air excess(o) aqurate

vO2hs(d) = vO2hs(c)-->yes(m ok)
No (m')--->(e)

(f)exhaust flow

Units cble/h cbleintro real data from cble flow measurement device)

Nm3 exhaust/h:vhs x Units cble/h
kg/h exhaust:vhs x density(tabulated)
Nm3/h air:m x A(stechiometric air required)