煤燃烧过程的深度控制是煤燃烧的最终目标。从气体和固体表面官能团转化2方面出发，针对煤粉预热燃烧过程4个还原性气氛区域内燃料的C/O/N元素迁移规律进行分析；从气体转化分析可得，整个过程的C主要以CO和CO2气体形式释放，O主要伴随碳氧化物和NOx释放，而N在预热阶段主要以N2的形式释放，在燃烧阶段主要以NO2和NO的形式释放，其含氮形式与和燃烧室顶部的距离有关；从固体官能团转化分析可得，原煤经历预热过程后，其表面的含碳双键和含氮官能团种类增多；在燃烧室的3个还原性区域内，燃料表面的含碳双键被多次消耗和生成，表面的吸附氧被多次释放和吸附，含氮官能团种类发生变化；预热半焦和400 mm处的固体样品生成的含碳双键最多，且重新生成吸附氧，因此这2个样品的活性最大；100 mm和900 mm处样品所含不稳定含N官能团种类最多，导致样品中N在这2个位置更易以气体形式释放，结果为煤燃烧过程中NOx的深度控制提供基础试验数据支撑。

The deep control of the coal combustion process is the ultimate goal pursued by coal combustion researchers. Based on the gas conversion and the solid functional group conversion,the C/O/N element migration discipline of the fuel in the four reducing atmosphere regions was mainly analyzed and elaborated during the pulverized coal preheating combustion process. From the gas transformation analysis,it can be obtained that the carbon element in the whole process is mainly released in the form of CO and CO2,the oxygen element is mainly released with gaseous carbon oxide and nitrogen oxide,and the nitrogen element is mainly released in the form of N2 during the preheating stage. It is mainly released in the form of NO2 and NO during combustion stage,its nitrogen-containing form is related to the distance from the top of the combustion chamber. From the analysis of solid functional group transformation,it can be seen that the types of carbon-containing double bonds and nitrogen-containing functional groups on the surface of raw coal increase after preheating. In the three reducing regions of the combustion chamber,the carbon-containing double bonds on the fuel surface are consumed and generated for many times,the adsorbed oxygen on the surface is released and adsorbed for many times,and the types of nitrogen-containing functional groups also change. The preheated char and the solid sample at 400 mm generate the most carbon-containing double bonds and there is the regeneration of adsorbed oxygen,thus the samples generated at these two positions are the most active. The samples at 100 mm and 900 mm contain the most types of unstable N-containing functional groups,which makes the nitrogen in the sample easier to be released in the form of gas at these two locations. The experimental results can provide basic experimental data support for the depth control of NOx during coal combustion.

0 引言

1 试验

   1.1 试验装置和原理

   1.2 燃料特性

   1.3 试验工况

2 结果与分析

   2.1 预热器内的C/O/N元素转化分析

   2.2 燃烧过程的C/O/N元素转化分析

3 结论