Air preheater for industrial boiler spare parts combustion air preheater
Air Preheaters(APH) Brief Introduction
1. Air Preheaters (APH) is the Shell and tube type Heat Exchangers used for preheating the air which is fed to the boiler or furnaces/kilns for combustion of fuels. Its primary objective is to extract the waste heat from the flue gases leaving the boiler.
2. Dehai Boiler Company manufacture Air Preheaters and are given as a standard side accessory along with the main equipment – Boiler, in a Packaged Type Boiler, Combi Boilers.
Tubular type Air Preheater
1. Tubular preheaters consist of straight tube bundles which pass through the outlet ducting of the boiler and open at each end outside of the ducting.
2. Inside the ducting, the hot furnace gases pass around the preheater tubes, transferring heat from the exhaust gas to the air inside the preheater.
3. Ambient air is forced by a fan through ducting at one end of the preheater tubes and at other end the heated air from inside of the tubes emerges into another set of ducting, which carries it to the boiler furnace for combustion.
Air pre heater Purpose
1. The purpose of the air preheater is to recover the heat from the boiler flue gas which increases the thermal efficiency of the boiler by reducing the useful heat lost in the flue gas.
2. As a consequence, the flue gases are also conveyed to the flue gas stack (or chimney) at a lower temperature, allowing simplified design of the conveyance system and the flue gas stack. It also allows control over the temperature of gases leaving the stack (to meet emissions regulations, for example).
3. It is installed between the economizer and chimney.
1. Preheated air increases combustion rate and then increases steam generations of boiler.
2. Due to higher temp. of air,furnace temp.increases,so low grade coal can be burnt efficiently.
3. Air heated by heat of exhaust gases.It reduces fuel consumptions.Therefore thermal efficiency of boiler increased.
staggered arrangement /in-line arrangement
staggered arrangement /
Sealing of pipe and plate
Packing heat- resistant material/
a,when gas scours external tube, welcoming smoke tubes have protective tile
b,when gas scours inside tube,wear casing pipes are installed in gas inlet