FIELD: power industry.
SUBSTANCE: invention relates to the field of power engineering. Method of nitrogen oxide exhaust reduction during oxygen fuel combustion involves feed of at least one primary gas flow (15) and at least one secondary gas flow (16) into furnace (11) of boiler (10) with circulating liquefied layer, where primary gas (15) and secondary gas (16) are obtained by mixing oxygen and circulating fuel gas. Oxygen content in the primary gas (15) is controlled so as to form recovery zone (I) at the furnace (11) bottom, and oxygen content in the secondary gas (16) is controlled so as to form oxidation zone (II) above recovery zone (I), while oxygen content in the primary gas (15) and secondary gas (16) is controlled by changing oxygen to circulating flue gas ratio in the aforementioned gas flows (15, 16). Two or more secondary gas flows are fed to furnace (11) at two or more different levels. Oxygen content is maintained different in secondary gas flows fed at different levels. Oxygen (24) and circulating flue gas (25) are mixed by mixing devices connected to furnace (11), directly before feeding primary gas (15) or secondary gas (16) to furnace (11). Furnace temperature is controlled by changing oxygen content in the primary gas (15) and/or in the secondary gas (16).
EFFECT: reduced nitrogen oxide exhaust during oxygen fuel combustion.
6 cl, 1 dwg
