What is the purpose of forced draft fans in a boiler?

Forced draft fans play a crucial role in the operation of a boiler by supplying air to the furnace. This air is essential for the combustion process, as it provides the oxygen needed to ignite and burn the fuel efficiently. The presence of the forced draft fan ensures that there is a consistent and controlled flow of air, which optimizes the combustion process, improves fuel efficiency, and helps maintain stable burner operation.

By delivering the appropriate amount of air directly into the combustion zone, these fans help achieve better combustion conditions, which can lead to more complete combustion of the fuel. This not only enhances the boiler's thermal efficiency but also minimizes pollutants and emissions, contributing to a cleaner operation overall.

In contrast, other functions mentioned do not align with the primary role of forced draft fans. Removing smoke from the stack is typically the function of stack fans or exhaust systems, cooling the combustion chamber may be handled by different cooling systems or processes, and oxidizing the fuel relates to the chemical reaction of combustion rather than the mechanical delivery of air. Thus, the focus of forced draft fans is primarily on providing the necessary air supply for fuel combustion.