Boiler Air Cap - Heat-Resistant Steel Air Cap

Captive-Power-Plant Circulating Fluidized Bed Boiler Air Cap

The boiler air cap is the air-distribution device of the boiler and plays a key role in its safe and economical operation. Small boiler air caps feature smaller orifice diameters and better air-distribution uniformity, but wear caused by an overly small design spacing is common. Large air caps feature larger orifice diameters; after reaching critical fluidization the turbulence intensity is greater, and their larger design spacing effectively avoids the wear caused by air caps blowing against each other, giving them a longer service life.

The air cap is a key component of the circulating fluidized bed boiler for achieving uniform air distribution and maintaining proper gas-solid two-phase flow inside the furnace for safe operation. It makes air distribution more uniform, and directional air caps can control the flow direction of the gas-solid two-phase flow, facilitating the discharge of large slag.

Air caps can be divided intootoo two main types by shape: bell-shaped air caps and unidirectional air caps. The former have smaller air orifices and higher air velocity, are prone to wear and have greater resistance, but the water-cooled wind box of the air-distribution plate is less prone to slag leakage; the latter have larger air orifices, slower air velocity, lower resistance and are less prone to wear.