模拟分解炉中煤焦燃烧生成NO的特性

NO formation from coal char combustion in cement precalciner

对国内水泥行业中几种煤焦在模拟的分解炉中 NO生成特性进行了研究, 考察了煤种、温度、生料对焦炭氮的释放特性的影响, 探讨了焦炭氮在工业分解炉中的释放机理. 研究结果表明, 不同煤种的 NO生成特性有较大的不同; 温度对NO的生成特性也有明显的影响, 基本随温度的升高而加大, 但有时也有下降现象; 生料的加入大大加速了NO的生成速率和转化率, 表明生料对 NO生成有显著的催化作用. 工业分解炉中产生的NO主要来源于燃料NO, 焦炭氮转化为NO的概率主要有两个互相竞争的反应决定: 包括 N的氧化反应和 NO的还原反应.

In a bench scale precalciner, the characteristics of NO release from coal char combustion were investigated in various conditions (different temperatures and presence of cement raw meal). The mechanism of NO formation was also discussed. The results indicated that the characteristics of NO emission from three kinds of chars were obviously different because of coal physical structure and chemical properties. The rate of NO formation increased with increasing temperature, however, sometimes the phenomenon was irregular. The rate and amount of NO formation clearly rose in the presence of cement raw meal, which suggested that cement raw meal showed distinct catalytic effect on NO formation. NO originated mainly from the oxidation of fuel nitrogen in the industrial precalciner. The conversion of char-N to NO was controlled by two competitive reactions: oxidation of fuel nitrogen and reduction of NO.