Abstract: The emission of NO_x when coal was burning in O₂/CO₂ was compared with the case of burning in air, and the effects of temperature and excess air ratio on NO_x formation were analyzed by using a one-dimensional drop-tube furnace. The formation and reduction mechanisms of NO_x in O₂/CO₂ were studied.There was a NO_x peak in both two atmospheres, and the peak of high volatile matter coal appeared much earlier than the peak of low volatile matter coal.The peak in O₂/CO₂ atmosphere appeared earlier than the peak in air and the peak value was lower than that in air.The amount of NO_x increased quickly with temperature in air, but the amount of NO_x changed slowly with temperature in O₂/CO₂ atmosphere.In both atmospheres the NO_x peak value increased with excess air ratio.The peak value of high volatile matter coal in O₂/CO₂ was lower than that in air but the low volatile matter coal was less affected.

Key words: 环境工程, O₂/CO₂, NO_x, 煤燃烧

摘要： 利用一维沉降炉，对3种煤在O₂/CO₂和空气两种气氛下燃烧NO_x析出特性进行了比较，分析了炉膛温度、过量空气系数对NO_x生成量的影响，并对O₂/CO₂气氛下NO_x的生成和破坏机理进行了分析.研究发现两种气氛下NO_x都有一个峰值出现，挥发分含量高的煤种峰值靠前, 挥发分含量低的煤种峰值靠后，O₂/CO₂条件下，峰值出现较空气条件下提前且有所下降;空气条件下NO_x的生成量随温度提高较快地增加，而O₂/CO₂气氛中NO_x的生成量随温度变化比较缓慢;在两种气氛下NO_x的峰值均随过量空气系数的增加而增加，高挥发分煤在O₂/CO₂气氛下NO_x峰值低于空气条件下峰值，而低挥发分煤则受影响较小.

关键词: 环境工程, O₂/CO₂, NO_x, 煤燃烧