煤燃烧中NO_x的来源和抑制其生成的有效措施

Origin of NO_x in Coal Combustion and the Countermeasures to Inhibit its formation

煤燃烧中产生的ＮＯ＿ｘ是不可忽视的大气污染源。根据其生成机理，它主要来自煤中氮的氧化以及高温下空气中Ｎ＿２和Ｏ＿２的反应。烟气中ＮＯ＿ｘ的浓度范围很宽，从２００至２５００ｍｇ／ｍ￣３，影响因素有燃烧温度、空气过剩系数、煤种和燃烧器类型等。在煤燃烧中采取适当措施，可以有效地降低ＮＯ＿ｘ浓度，如降低燃烧温度、分段燃烧、优化空气过剩系数、烟气部分循环和选用含氨量低的煤等。

NO_x derived from coal combustion is an unnegligible air pollu-tion. According to its formation mechanism , NO_x essentially derives from oxidation of nitrogen in coal and blast air. Its concentration in flue gas with a larger ranger from 200 to 25O0 mg/m￣3 is mainly influenced by combustion temperature, air sur-plus index, coal and burner type etc. It can effectively sink the concentration of NO_x,if following measures are taken,decreasing the combustion temperature,multi-stage-burning,optimizing air surplus index,partially recycling flue gas and selecting coal with low nitrogen content etc.