초록 ▼

A method for reducing NO.sub.x emissions from the combustion of carbonaceous fuels using two sequential stages of partial oxidation followed by a final oxidation stage. In the first stage, substoichiometric air condition of about 0.55 to 0.75 is used in a plug flow fashion, while second stage combus

A method for reducing NO.sub.x emissions from the combustion of carbonaceous fuels using two sequential stages of partial oxidation followed by a final oxidation stage. In the first stage, substoichiometric air condition of about 0.55 to 0.75 is used in a plug flow fashion, while second stage combustion is performed at a stoichiometric ratio of about 0.80 to 0.99. As the second stage combustion products are cooled by radiant heat transfer to the boiler furnace walls, overfire air is added to produce an stoichiometric ratio of about 1.05 to 1.25 to complete the combustion process. In this manner, the formation of thermal NO.sub.x is reduced.

대표청구항 ▼

[ What is claimed is:] [1.]1. A method for reducing nitrogen oxide (NO.sub.x) emissions formed during the combustion of a carbonaceous fuel, said method comprising the steps of:a) introducing a carbonaceous fuel containing fuel-bound nitrogen into any carbonaceous fuel burner, wherein primary carrie

[ What is claimed is:] [1.]1. A method for reducing nitrogen oxide (NO.sub.x) emissions formed during the combustion of a carbonaceous fuel, said method comprising the steps of:a) introducing a carbonaceous fuel containing fuel-bound nitrogen into any carbonaceous fuel burner, wherein primary carrier air mixed with a carbonaceous fuel and preheated secondary air at a temperature in a range of about 400.degree. F. to 700.degree. F. is added in a first stage to produce a fuel gas at a stoichiometric air-to-fuel ratio in a range of about 0.55 to 0.75;b) introducing the fuel gas from the first stage into a second stage of partial oxidation in a boiler furnace by introducing preheated tertiary air into the fuel gas to yield an overall stoichiometric air-to-fuel ratio of about 0.80 to 0.99;c) introducing the fuel gas from the second stage of partial oxidation in the boiler furnace, the fuel gas flowing through a radiant section of the boiler furnace to produce a flue gas; andd) introducing the gas into a third stage of oxidation wherein preheated overfire air is introduced into the boiler furnace to substantially complete combustion.