Air heater has an important role to improve the efficiency of the high thermal of the steam boiler by utilizing the thermal energy with low temperature flue gas from the steam boiler before being discharged into atmosphere. Air heater doing heat transfer between flue gas with combustion air. Air heater cooling the flue gas air for every 40oF (22oC) will increase the overall steam boiler efficiency is about 1%.
Apolytech air heater is proven to be effective in saving the fuel required for the boiler.
Air heater requires a large amount of heat transfer surface per unit of heat recovered because of the relatively small difference between the flue gas temperature and temperature of combustion air. Air heater is typically located behind steam boiler, where it receives hot flue gas form the economizer and cold combustion air from the force draft fan. The hot air produced by air heater to enhance combustion of all fuel and is needed for drying fuel like coal in stoker steam boiler.
The air heater is usually the last heat trap in the steam boiler. Air heater exit gas temperature should be higher than the corrosion limit of the AH internals and the downstream equipment. Air heaters generally operate in a temperature range of 450–120°C