Heat transfer of air preheater thermal conductivity of air preheater can be divided into and regeneration in two broad categories. Thermal conductivity type air preheater is most commonly used in tube air preheater. With the improvement of boiler parameters and capacity increases, increases in heating surface of tubular air preheater, which brought difficulties to the arrangement of tail heating surfaces. Therefore, in most of the large capacity, compact structure, lighter Rotary air preheater.
Tubular type
Tube type air preheater's main component is a thin-walled steel tube heat transfer. Tube type air preheater are cubelike, staggered tube perpendicular to each other, the ends welded top and bottom tube plate. Tube air preheater with intermediate tube in the tube plate and smoke down the pipe and the preheater, the horizontal through the air preheater, complete thermal conduction.
Advantages of tubular air preheater sealing, high heat transfer efficiency, ease of manufacture and processing, so multiple applications in power plant boilers and in industrial boilers. The disadvantage of tubular air preheater is bulky, the pipe is easy fouling, not easy to clean flue gas inlet and is easy to wear.
Rotary type
Rotary air preheater is the most common form of regenerative air preheater, it is the use of flue gas and air alternately through the metal heating surface to heat the air. Classified according to the way of Rotary air preheater heating surface of rotation and hood turned two, the furnace's two three-point position air preheater heating surface of Rotary air preheater.
Rotors of Rotary air preheater consists of a cylindrical rotor and fixed cylinder-shaped shell and driving device.