Preheating combustion is a promising novel low-nitrogen technology. The coke generation and conversion behavior in the preheater and combustion chamber are studied in this paper. The particle size distribution, apparent morphology, specific surface area, pore structure distribution and combustion reactivity of the coke can be analyzed respectively with the particle size analyzer, scanning electron microscope, automatic specific surface area analyzer and Raman spectrometer. The results show that the preheated char generated by the preheating process has some merits: the particle size is smaller, specific surface area is larger, the pore structure is more developed and combustion reactivity is higher. In the down-fired combustor, the degree of particle breakage, apparent morphology, specific surface area and pore structure are influenced by the combustion reaction intensity. Combining the analysis of the graphite stable structure and the active carbon defect structure, the combustion reactivity order of four samples is: 100 mm > 400 mm > preheated char> 900 mm. This paper provides experimental support and theoretical analysis for this technology to achieve deep control of nitrogen.

预热燃烧是一种有前途的新型低氮技术。研究了预热器和燃烧室中焦炭的产生和转化行为。焦炭的粒度分布，表观形态，比表面积，孔结构分布和燃烧反应性可以分别用粒度分析仪，扫描电子显微镜，自动比表面积分析仪和拉曼光谱仪进行分析。结果表明，预热过程产生的预热焦炭具有以下优点：粒径较小，比表面积较大，孔结构更发达，燃烧反应性较高。在向下燃烧的燃烧器中，颗粒破裂的程度，表观形态，比表面积和孔结构受燃烧反应强度的影响。结合对石墨稳定结构和活性炭缺陷结构的分析，四个样品的燃烧反应顺序为：100 mm> 400 mm>预热炭> 900 mm。本文为该技术实现氮的深度控制提供了实验支持和理论分析。