The air preheater is an auxiliary component of steam generating power plant.
Recuperative and regenerative preheaters are two types of heat exchangers used in steam power plants to recover heat and increase the efficiency of the thermal power station. The major difference between these two types of preheaters lies in the way they store and transfer heat.
The recuperative type air heater comprises of a group of steel tubes. The flue gases are passed through the tubes whereas air flows externally to the tubes. The heat of flue gases is transferred to the air.
The regenerative type air pre-heater comprises of slowly moving drum that is fabricated using corrugated metal plates. In this preheater, on one side of the drum flue gases flow continuously, while on another side, the air flows. This action permits the transference of heat of flue gases to the air being supplied to the furnace for coal combustion.
Both types of preheaters have their own advantages and disadvantages, and the choice between the two depends on the specific requirements of the process and the available resources.