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

The air preheater is located in the region of the heating furnace where the flue gas temperature is low, reclaiming the excess heat of the flue gas, reducing the exhaust gas temperature. At the same time, the required air for combustion is preheated, raising the initial temperature of the fuel and air, enhancing the ignition and combustion process of the fuel, reducing incomplete heat loss of the fuel, and further improving the thermal efficiency of the heating furnace.