How do you calculate the excess air in boiler?

To calculate excess air in a boiler, you first need to determine the theoretical air requirement for complete combustion based on the fuel's composition. Then, measure the actual amount of air supplied to the boiler. The excess air percentage can be calculated using the formula:

[ \text{Excess Air (%)} = \left( \frac{\text{Actual Air} - \text{Theoretical Air}}{\text{Theoretical Air}} \right) \times 100 ]

This calculation helps in optimizing combustion efficiency and reducing emissions.