Most fluidized bed combustion boiler in operation for this type is Atmospheric Fluidized Bed Combustion (AFBC) boiler. This equipment is just shell of conventional boiler which is coupled with fluidized bed combustor and the system has been installed together with water wall tube boiler.
Coal is crushed into size 1 – 10 mm depend on the level of coal and type of feed air then distribute them into combustion chamber. Atmospheric air which acts as fluidization and combustion air is inserted by pressure after preheated by exhaust flue gas.
Tubes in the bed carrying water generally act as an evaporator. The flue gas is the product of combustion will pass through superheater and then flow into economizer. From economizer flue gas flow to air preheater then dust collector before being discharged into atmosphere.