掺杂金属化合物强化煤焦-NO反应的析因试验研究

Factorial experimental study of the char-NO reaction intensified by doped metallic compounds

为揭示影响煤焦-NO反应的主要因素与NO还原率之间的定量关系,也为研发燃煤锅炉实际运行阶段控制NO排放新技术,采用立式石英固定床反应器,研究掺杂钙基或铁基金属化合物的煤焦对NO异相还原反应的影响。结果表明,钙基、铁基、温度*钙基(交互作用)和温度对煤焦还原NO有显著影响,并且影响的显著性依次增强;基于析因试验设计方法,建立了NO还原率积分值与煤种属性参数、温度、金属化合物添加量的耦合预测模型;温度的升高有利于煤焦还原NO,固定碳含量更高、灰分含量更低的织金无烟煤焦对NO的还原作用强于瓮安烟煤焦的还原作用;在相同温度下,掺杂铁基或钙基金属化合物对不同种类煤焦还原NO的催化效果有区别,但按等比例复合后的铁基钙基化合物催化效果均表现为协同作用。

In order to reveal the quantitative relationship between the main factors affecting char-NO reaction and NO reduction rate,and to develop new technology of NO emissions control during coal-fired boilers operation stage,the effects of calcium-based and iron-based catalysts on heterogeneous reduction between NO and char were investigated using a vertical fixed bed reactor in this study. The results show the effect of the catalyst on NO heterogeneous reduction is determined by temperature,type of char and catalyst with more significant influence. A coupling model to predict NO reduction according to the parameters mentioned above was established based on a factorial experiment design. The increase of temperature can enhance the heterogeneous reduction between NO and char. ZJ anthracite char with more fixed carbon content and less ash content has higher activity in heterogeneous reduction than WA bitumite char. At the same temperature condition,the catalytic effects of calcium-based and iron-based compounds to the heterogeneous reduction of NO by different chars are different. On the other hand,the catalytic effect of composite metallic compounds mixed by calcium-based and iron-based in the same ratio is synergy.