What is the effect of too much excess air on combustion efficiency?

When excess air is introduced into the combustion process, it leads to a dilution of the fuel-air mixture. While a certain amount of excess air is necessary to ensure complete combustion and to minimize the production of pollutants such as carbon monoxide, an excessive amount can cause inefficiencies.

With too much excess air, the temperature of the flame decreases because the additional air absorbs heat that would otherwise contribute to the combustion process. This cooling effect can prevent the fuel from burning completely. As a result, the combustion becomes less efficient, leading to a decrease in the energy produced per unit of fuel consumed.

Furthermore, excess air can cause the condition known as flue gas dilution, where the amount of useful heat that can be extracted from the combustion gases reduces significantly. This further contributes to lower combustion efficiency.

Ultimately, maintaining the right balance of air in the combustion process is crucial for optimizing combustion efficiency. Too much excess air detracts from this balance, leading to reduced efficiency and increased operational costs.