State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, Ningxia University
College ofChemistry and Chemical Engineering, Ningxia University
Institute of Clean Coal Technology, East China University of Scienceand Technology

Study on the ignition characteristics of coal is the theoretical basis for realizing the high-efficient and clean utilizationof coal. The alkali metals such as K and Na in coal are released into the gas phase during combustion and enter the system, which can easily cause high temperature corrosion of the reactor, fouling of the heating surface and slagging in thefurnace. Based on the single-particle coal ignition detection platform, the ignition and alkali metal Na* and K* radiationcharacteristics of single-particle Yangchangwan (YCW) bituminous coal and Naomaohu (NMH) lignite during combustionwere investigated under different oxygen volume flow rates. High-speed camera technology was used to capture theflame evolution process during single-particle coal ignition, and hyperspectral imaging technology was used to measurethe spontaneous emission spectra of alkali metals Na* and K* in the flame to obtain the spatial release behavior of alkalimetals. The results show that the ignition process of different types of coal is different. The enveloping flame is formed inthe combustion process of volatile matter in the YCW coal particles, while the ignition reaction of the NMH coal is moreintense without enveloping phenomenon due to its high volatile matter content, and the flame brightness in the whole ignitionprocess is stronger than that of the YCW coal. The increase of oxygen can promote the ignition of coal particles, withthe increase of oxygen volume flow, the ignition delay time of the YCW coal and the NMH coal decreases, and the ignitiondelay time of the NMH coal is smaller than that of the YCW coal. When the fire occurs, the flame brightness is thebrightest, and the flame shape is relatively smooth and stable. The radiation characteristics of alkali metals Na* and K* insingle-particle YCW coal and NMH coal during ignition and combustion are different from that in coke combustion process,in which the radiation intensity of Na* and K* is the strongest. Na* has a release peak both in the volatile reactionprocess and coke reaction process, but K* radiation intensity does not have an obvious release peak in the volatile reactionprocess and coke combustion process. When oxygen content increases, the release time of alkali metals from the YCWcoal and the NMH coal is gradually advanced, and the beginning time of alkali metal radiation from the NMH coal is lessthan that from the YCW coal. In addition, the analysis of the ignition process of single-particle coal shows that the releaseintensity of alkali metals Na* and K* in the peripheral position of the combustion flame is stronger than that in the centralposition.

国家自然科学基金资助项目(22108132, 22008126)；宁夏重点研发计划资助项目(2019BCH01001)

李金云，谢非，宋旭东，等. 基于光学诊断技术的单颗粒煤着火及碱金属辐射特性[J]. 煤炭学报，2023，48(4)：1727−1735

LI Jinyun，XIE Fei，SONG Xudong，et al. Single-particle coal ignition and alkali metal radiation characteristics based on optical diagnosis technology[J]. Journal of China Coal Society，2023，48(4)：1727−1735