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 low-temperature region of the heating furnace flue gas, reclaiming the waste 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, enhancing the ignition and combustion process of the fuel, reducing the unutilized heat loss of the fuel, and further improving the thermal efficiency of the heating furnace.