An FD fan, or forced draft fan, is used to supply controlled combustion air to boilers, furnaces and other fired equipment. Its job is to push air into the combustion chamber so that fuel can burn efficiently and the resulting flue gases can move through the system at the required rate. FD fans are key components in power plants, industrial boilers, kilns and many process heaters, including those used around mines and mineral-processing plants.
In a typical boiler or furnace system, the FD fan draws ambient air through filters and dampers and forces it into the burner windbox or air registers. The pressure generated by the fan ensures that enough air reaches the burner nozzles at the correct velocity and distribution pattern. This air mixes with fuel—coal, oil, gas or waste fuels—to create a stable flame and complete combustion, minimising unburned fuel and reducing emissions such as carbon monoxide and soot.
FD fans also play an important role in controlling furnace pressure and heat transfer. By adjusting the FD fan flow (often through dampers or variable-frequency drives), operators can regulate the mass flow of air and flue gas through the boiler or kiln. This directly affects steam production, temperature profiles and overall efficiency. FD fans often work together with ID (induced draft) fans, which pull flue gases out of the system; the combination of FD and ID fans keeps furnace pressure slightly negative or near zero, depending on design.
In industrial plants serving mining and heavy industries, FD fans are used in process heaters, rotary kilns, drying ovens and smelting processes. Many of these systems require tight control of air and fuel ratios to maintain product quality and protect refractory linings and heat exchangers. FD fans provide the reliable airflow needed to support these demanding operations, often in harsh environments with dust and elevated temperatures.
Because FD fans handle combustion air, they are typically centrifugal or high-pressure axial fans designed for continuous duty. They may be equipped with inlet vanes or advanced control systems to match airflow to load, saving energy while keeping emissions within permit limits. Materials, seals and bearings are selected to withstand temperature, contaminants and frequent load changes.
In summary, an FD (forced draft) fan is used to supply and control combustion air for boilers, furnaces and related fired equipment. By pushing air into the system at the right pressure and flow, the FD fan supports efficient, stable and clean combustion in a wide range of industrial and mining-related applications.
