The invention discloses a method for combusting a fuel reburning low-
nitrogen oxide and belongs to a clean
combustion method for a
coal-fired boiler. Secondary medium air is used as a
powder conveying medium of a
combustor on the upper layer of the main
combustion area of the boiler,
coal powder used as a reburning fuel is conveyed into the boiler, the secondary medium air is used as distributed air of the
combustor, the secondary air of the
combustor on the upper layer is reduced correspondingly, the distributed air in the reburning area is reduced correspondingly, low excess air
combustion is formed, the distributed air in a
hearth is not enough, and finally over fire air (OFA) complements the required air; and the mixed medium of air and
fuel gas is used as the conveying medium of the
coal powder of the combustor of the upper layer, and the coal powder with the conventional
fineness is conveyed into the boiler from the combustor on the upper layer by using a coal mill and a powder making
system and is re-burnt and denitrated, and is burnt out by OFA. The problem that the reburning fuel and the
fuel gas are not mixed uniformly, the reduction time is short, and the denitration efficiency is low is solved, the original design working conditions of maximum continuous
evaporation capacity of the boiler and the like are not influenced, transformation is easy to realize, and the running cost is low.