Air preheaters are heat exchange devices that utilize the excess heat from the exhaust flue gas of a furnace to heat the air required for combustion. Their purpose is to reduce flue gas temperatures and enhance the overall thermal efficiency of the furnace.

The air preheater is positioned in the low-temperature area of the boiler flue gas, reclaiming the excess heat of the flue gas, reducing the exhaust gas temperature, and simultaneously preheating the required air, enhancing the initial temperature of fuel and air, strengthening the ignition and combustion process of the fuel, reducing incomplete heat loss of the fuel, and further improving the thermal efficiency of the heating boiler.