基于光学诊断技术的单颗粒煤着火及碱金属辐射特性  

Single-particle coal ignition and alkali metal radiation characteristics based on optical diagnosis technology

作　　者：李金云 谢非 宋旭东 白永辉 吕鹏 王焦飞 苏暐光[1,2] 于广锁 LI Jinyun;XIE Fei;SONG Xudong;BAI Yonghui;LÜPeng;WANG Jiaofei;SU Weiguang;YU Guangsuo(State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering,Ningxia University,Yinchuan 750021,China;College of Chemistry and Chemical Engineering,Ningxia University,Yinchuan750021,China;Institute of Clean Coal Technology,East China University of Science and Technology,Shanghai 200237,China)

机构地区：[1]宁夏大学省部共建煤炭高效利用与绿色化工国家重点实验室,宁夏银川750021 [2]宁夏大学化学化工学院,宁夏银川750021 [3]华东理工大学洁净煤技术研究所,上海200237

出　　处：《煤炭学报》2023年第4期1727-1735,共9页Journal of China Coal Society

基　　金：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)。

摘　　要：煤着火特性研究是实现煤高效和清洁利用的理论基础,煤中所含的K和Na等碱金属在燃烧过程中释放到气相中并进入系统容易引起反应器高温腐蚀、受热面结垢和炉内结渣等问题。单颗粒煤燃烧形式简单,其相关研究结果可以更好地揭示煤着火特性。基于单颗粒煤着火检测平台,探究了不同氧气体积流量下单颗粒羊场湾(YCW)烟煤和淖毛湖(NMH)褐煤燃烧过程中着火特性及碱金属Na^(*)、K^(*)辐射特性。利用高速摄像技术捕捉单颗粒煤着火过程中火焰演变过程,结合高光谱成像技术测定火焰中碱金属Na^(*)和K^(*)自发辐射光谱,获得碱金属的空间释放行为。结果表明:不同煤种着火过程不同,YCW煤颗粒挥发分燃烧过程中形成包络型火焰,NMH煤则由于挥发分高,着火反应比较剧烈,未出现包络现象,且整个着火过程中火焰亮度比YCW煤强。氧气增加对煤颗粒着火具有促进作用,随着氧气体积流量增加,YCW煤和NMH煤着火延迟时间减小,且NMH煤着火延迟时间小于YCW煤。着火产生时火焰亮度最亮,火焰外形相对平缓稳定。单颗粒YCW煤和NMH煤着火燃烧过程中碱金属Na^(*)、K^(*)辐射特性在煤颗粒着火后的挥发分反应过程和焦炭燃烧过程中不同,其中,挥发分反应过程Na^(*)和K^(*)辐射强度最强,Na^(*)在挥发分反应过程和焦炭反应过程中分别存在释放峰,但K^(*)辐射强度在挥发分反应过程和焦炭燃烧过程并未出现明显的释放峰。当氧气增加,YCW煤和NMH煤碱金属释放时间逐渐提前,且NMH煤碱金属辐射开始时间小于YCW煤。另外,就单颗粒煤着火过程分析得出,燃烧火焰外围位置比中心位置碱金属Na^(*)和K^(*)释放强度更强。Study on the ignition characteristics of coal is the theoretical basis for realizing the high-efficient and clean utilization of 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 the furnace.Based on the single-particle coal ignition detection platform,the ignition and alkali metal Na^(*)and K^(*)radiation characteristics of single-particle Yangchangwan(YCW)bituminous coal and Naomaohu(NMH)lignite during combus-tion were investigated under different oxygen volume flow rates.High-speed camera technology was used to capture the flame evolution process during single-particle coal ignition,and hyperspectral imaging technology was used to measure the spontaneous emission spectra of alkali metals Na^(*)and K^(*)in the flame to obtain the spatial release behavior of alkali metals.The results show that the ignition process of different types of coal is different.The enveloping flame is formed in the combustion process of volatile matter in the YCW coal particles,while the ignition reaction of the NMH coal is more intense without enveloping phenomenon due to its high volatile matter content,and the flame brightness in the whole igni-tion process is stronger than that of the YCW coal.The increase of oxygen can promote the ignition of coal particles,with the increase of oxygen volume flow,the ignition delay time of the YCW coal and the NMH coal decreases,and the igni-tion delay time of the NMH coal is smaller than that of the YCW coal.When the fire occurs,the flame brightness is the brightest,and the flame shape is relatively smooth and stable.The radiation characteristics of alkali metals Na^(*)and K^(*)in single-particle YCW coal and NMH coal during ignition and combustion are different from that in coke combustion pro-cess,in which the radiation intensity of Na^(*)and K^(*)is the strongest.Na^(*)has a release peak both in the volatile reaction

关 键 词：单颗粒煤燃烧 火焰图像 碱金属辐射特性 光学诊断 

分 类 号：TQ545[化学工程—煤化学工程]