Method for reducing nitrogen oxides

摘要

A burner apparatus and method for reducing nitrogen oxides that are formed during combustion of gaseous fuel. Primary gaseous fuel and excess oxidant are premixed to form a fuel/oxidant mixture which is introduced into and combusted within a primary combustion zone. Primary combustion products are introduced into a secondary combustion zone. Secondary gaseous fuel is also introduced into the secondary combustion zone and is preferably mixed with the primary combustion products. The mixture of secondary gaseous fuel and primary combustion products is combusted in a secondary combustion zone. A portion of the secondary combustion products are internally recirculated into the secondary combustion zone. The overall combustion products can be externally recirculated and introduced into the primary combustion zone. A portion of the fuel/oxidant mixture, with or without the recirculated overall combustion products, can be bypassed around the primary combustion zone and introduced into the secondary combustion zone.