Method and apparatus for NOx reduction in flue gases

摘要

In a furnace having a primary combustion zone for combustion of a fuel and oxidant, an in-furnace method for reducing nitrogen oxides in combustion products generated in the primary combustion zone in which at least one fluid fuel selected from the group consisting of natural gas, hydrogen, C_xH_y compounds, C_xH_yO_z compounds and mixtures thereof in an amount in a range of about 2.0% to about 25% of a total heat input to the furnace and at least one nitrogenous compound selected from the group consisting of ammonia, amines, urea, cyanuric acid and mixtures thereof are injected into the furnace downstream of the primary combustion zone, forming an overall fuel-lean NO_x-reduction zone.