Please take a look at this calculation problem
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1. It is known that the oxygen content in the flue gas from the heating furnace is 5% and the CO2 content is 13%. What is the excess air coefficient α? Solution: α = (100 – CO2% – O2%) / (100 – CO2% – 4.76 × O2%) = (100 – 13 – 5) / (100 – 13 – 4.76 × 5) = 1.297. Answer: The excess air coefficient is 1.297. Question 1: What is the meaning of this formula? Question 2: What does 4.76 mean, and how is it determined? Why is the carbon dioxide content necessary? Since the formula α=20.9/20.9-O2 can be used to directly calculate α, the carbon dioxide content isn’t required. Which formula should be used in the calculations? Are there any relevant standards?
My understanding: Excess air coefficient = actual air volume/theoretical air volume = actual nitrogen volume/theoretical nitrogen volume. 100% - CO2% - O2% = actual amount of nitrogen; 100% - CO2% - 4.76% O2% = theoretical amount of nitrogen. 4.76% O2% represents the excess air amount, and 79% nitrogen converted to 21% oxygen is 3.76 times that amount
The formula α=20.9/20.9-O2 is likely incorrect.
If the volume percentages of nitrogen and oxygen in the flue gas are known, the air excess factor can be calculated directly without the need for CO2 concentration data. Reducing CO2 is used to calculate the N2 content.