Specifications Overfire Air Systems

Type:
An air staging system utilizing ports with two air zones to optimize emission reductions.


Function:
Diverts a portion of combustion air that otherwise would be supplied to the burners to another location downstream in the combustion process; cutting the amount of air supplied to the burners causes a fuel rich/oxygen lean zone to develop; NOx is suppressed and reduced as it passes through the fuel rich zone. The overfire air system completes the combustion process.

Design features:
Dual zone ports simultaneously provide air across the furnace to mix with combustibles well away from the walls, while also supplying air to mix with combustibles in the proximity of the ports; heavy-duty design is well suited for extreme conditions of utility boilers; on-line adjustability provides means to fine tune mixing and minimize NOx emissions.

NOx removal efficiencies:
Dependant upon burner design, arrangement and firing conditions, and the fuel being fired.