垃圾焚烧炉的高效稳定运行及减少NOx排放是目前城市生活垃圾焚烧过程中所面临的挑战。以某500t/d垃圾焚烧炉为对象,研究了城市生活垃圾(MSW)掺混高热值废弃物(ISW)下不同配风方案对燃烧过程、流场分布的影响和最佳选择性非催化还原(SelectiveNon-CatalyticReduction,SNCR)工艺参数。结果表明,不同各级一次风配比床层对应的最高温度基本不变,但增加炉排一二级风室配风,挥发分析出和固定碳燃烧提前,挥发分析出最大速率提高。良好的二次风喷入角度能有效组织炉内气流流动,在工况7下,炉内高温贴墙现象最轻,流线分布较合理,因此该工况下的二次风角度设置最合理。喷入SNCR还原剂显著减少NOx排放量,喷射速度为50m/s时,脱硝效率最高,可达33.96%。因此在实际使用中,建议采用合适的配风和二次风喷入角度,并结合SNCR技术进行NOx减排。

The efficient and stable operation of waste incinerators and the reduction of NOx(nitrogen oxides) emissions are the currently challenges faced in the process of municipal solid waste(MSW) incineration. Taking a 500 t/ d waste incinerator as an object, theeffects of different air distribution schemes on the combustion process, flow field distribution and the optimal selective non-catalytic reduction (SNCR) process parameters were investigated for MSW mixed with high calorific value waste (ISW). The results show that the maximum temperature corresponding to the bed layer of different levels of primary air ratios remains basically unchanged. However, the maximum rate of volatilization analysis out increases, and the combustion of volatile and fixed carbon is advanced by increasing the air distribution in the first and second air chambers of the grate. A good secondary air injection angle can effectively organize the airflow in the furnace.Under condition 7, the phenomenon of high temperature sticking to the wall in the furnace is the lightest, and the distribution of flowlines is also more reasonable, so the secondary air angle setting in this working condition is the most reasonable. After SNCR reductant injection, NOx emissions are significantly reduced, and the denitrification efficiency is highest when the injection speed is 50 m/ s, up to33.96%. Therefore, it is recommended to use suitable air distribution and secondary air injection angles and to combine with SNCR technology for NOx reductionin actual operation.

0 引言

1 垃圾焚烧炉与燃料

   1.1 垃圾焚烧炉模型建立

   1.2 燃料

   1.3 模型假设与基本思想

   1.4 基本守恒方程

2 模型验证

3 焚烧炉配风优化

   3.1 一二次风配比

   3.2 一次风炉排各级比例

   3.3 二次风角度优化

4 SNCR运行优化

   4.1 NOx模型和尿素SNCR模型

   4.2 喷入速度

5 结论