CO₂ % in Flue Gas
Theoretical (dry) CO₂ concentration in flue gas as a function of excess air - useful cross-check against stack analyser.
Actual CO₂ (dry)
12.92% v/v
Formula, assumptions, and limits
$$CO_2\% = \frac{CO_2\text{,max}}{\lambda}$$
Inversely proportional to λ. A boiler tuned to λ = 1.2 on HFO should read ≈ 13 % CO₂ dry - higher = under-aired (smoke); lower = over-aired (efficiency loss).
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $CO_{2,\text{max}}$ | Stoichiometric CO₂ max | % v/v | fuel property |
| $λ$ | Excess air factor | - | combustion analyser |
| $CO_2\%$ | Actual flue CO₂ | % v/v | result |
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