Pulverized coal firing equipment and burnup manner

摘要

PROBLEM TO BE SOLVED: To effectively reduce the emission of NOx by virtue of stagnant combustion gas upstream even in the case of a large-scale firing furnace and simultaneously make the feeding of after-air bring about a state of the after-air being mixed with the combustion gas as a whole downstream so as to reduce the release of harmful substances. ;SOLUTION: A pulverized coal-firing apparatus has a burner 2 from which pulverized coal and air are blown out into a firing furnace 1, primary after-air ports 5 for feeding primary after-air into the downstream part of the firing furnace, and secondary after-air ports 6 for feeding secondary after-air further downstream. This firing apparatus burns the pulverized coal blown out in air 3 in a manner of incomplete combustion under a condition of an excess of fuel so as to form a flame of reducing atmosphere 10, blows out primary after- air toward a stagnation region 12 which is spread to the periphery of the reducing atmosphere, and feeds secondary after-air toward a region of reducing atmosphere 10 further downstream. By feeding after-air in two, that is, primary and secondary steps and by different timing to the regions of combustion gas each differing in composition and nature from the other this firing apparatus efficiently reduces harmful substances, such as NOx and CO, in the exhaust.;COPYRIGHT: (C)1997,JPO