When should combustion of fuel in a boiler furnace be performed?

The combustion of fuel in a boiler furnace should be performed with a minimum of excess air. This approach is crucial for several reasons.

Firstly, using a minimum amount of excess air ensures that there is enough oxygen available for the complete combustion of the fuel, which maximizes efficiency. If too little air is supplied, incomplete combustion can occur, leading to the production of carbon monoxide and unburned fuel, which are both inefficient and potentially dangerous.

Secondly, minimizing excess air reduces the amount of heat carried away by the flue gases. Each extra unit of air that is supplied beyond what is necessary for complete combustion absorbs heat, thus lowering the overall thermal efficiency of the boiler. This is particularly important in maintaining energy efficiency and reducing fuel costs.

Finally, operating with the right amount of air helps to maintain optimal combustion temperatures, reducing the formation of nitrogen oxides (NOx), which are pollutants created during combustion due to high temperatures. By balancing the air-to-fuel ratio appropriately and minimizing excess air, the boiler can operate more cleanly and efficiently, making it a better choice for both performance and environmental considerations.