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 situated in the region of the heating furnace where the flue gas temperature is low, recovering the excess heat of the flue gas, reducing the exhaust gas temperature. At the same time, the required combustion air is preheated, increasing the initial temperature of the fuel and air, strengthening the ignition and combustion process of the fuel, reducing incomplete fuel heat loss, and further enhancing the heating furnace's thermal efficiency.