An air preheater is a heat exchange device that utilizes the waste heat from the tail gas of a heating furnace to heat the air required for combustion, aiming to reduce the tail gas temperature and improve the overall thermal efficiency of the heating furnace.

The air preheater is located in the low-temperature zone of the furnace flue gas, recovering the waste heat from the flue gas, reducing the exhaust gas temperature, and simultaneously preheating the air required for combustion. This raises the initial temperature of the fuel and air, strengthens the ignition and combustion process of the fuel, reduces the uncompleted heat loss in the fuel, and further improves the heat efficiency of the furnace.