What type of air is used to support combustion in a boiler?

The type of air used to support combustion in a boiler is primary air. Primary air is the air that is introduced directly into the combustion zone of the boiler to facilitate the burning of the fuel. It is essential for the initial combustion process, providing the necessary oxygen to react with the fuel. This air is typically heated and is mixed with the fuel before entering the combustion area, ensuring that the fuel ignites effectively and burns efficiently.

In contrast, secondary air is introduced after the initial combustion has started and is used to help complete the combustion process, improving efficiency and reducing emissions. Tertiary air, on the other hand, is sometimes used in specific advanced combustion systems to further enhance the combustion process, particularly in minimizing pollutants. Ambient air generally refers to the surrounding air in the environment, which may not be conditioned or appropriate for optimal combustion due to variations in temperature and composition. Thus, understanding the role of primary air is crucial in boiler operation and efficiency.