镧氧化物强化高炉喷吹煤粉燃烧机制
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摘要
镧氧化物(La2O3)具有卓越的化学催化性能,以某高炉生产现场入炉煤粉为原料研究La2O3对煤粉的助燃机理。利用实验室高温高压煤粉燃烧装置模拟高炉风口回旋区燃烧工况条件进行煤粉燃烧效率试验并收集未燃残炭,通过SEM观察分析未燃残炭,结合热重-差热分析La2O3对煤粉燃烧的助燃机制。结果表明,添加La2O3后煤粉燃烧效率明显提高,La2O3添加量在1. 5%时,煤粉燃烧效率提高了12. 33%,此时未燃残炭平均粒径比原煤未燃残炭平均粒径减小14. 5μm,外观形貌极不规则。La2O3在煤粉固定碳表面上形成瞬态金属氧化物La3+(CO-)3,削弱碳分子结构单元间的桥键结合力,改善煤粉颗粒的反应速率,促使挥发分提前释放,显著提高煤粉颗粒的燃烧反应性和煤粉的燃烧效率。
Lanthanum oxide( La2 O3) has excellent chemical catalytic performance.The combustion mechanism of La2 O3 on coal powder was studied by using pulverized coal from a blast furnace production site as raw material. The high temperature and high pressure pulverized coal combustion device was used to simulate the combustion conditions of the blast furnace tuyere in the blast furnace.The pulverized coal combustion rate test was conducted and the unburned carbon residue was collected. The unburned carbon was analyzed by SEM,and the thermal weight-differential thermal analysis was used to analyze the coal by La2 O3.The results show that the combustion rate of pulverized coal is obviously improved after adding La2 O3.When the amount of La2 O3 is 1.5%,the burning rate of pulverized coal is increased by 12.33%.At this time,the average particle size of unburned carbon residue is larger than that of unburned carbon residue of raw coal.The average particle size is reduced by 14.5 μm and the appearance is extremely irregular.La2 O3 forms transient metal oxide La3+( CO-)3 on the surface of pulverized coal fixed carbon,weakens the bridge bond between carbon molecular structural units,improves the reaction rate of pulverized coal particles,promotes the early release of volatiles,and significantly improves coal. The combustion reactivity of the powder particles improves the combustion efficiency of the coal powder.
Lanthanum oxide( La2 O3) has excellent chemical catalytic performance.The combustion mechanism of La2 O3 on coal powder was studied by using pulverized coal from a blast furnace production site as raw material. The high temperature and high pressure pulverized coal combustion device was used to simulate the combustion conditions of the blast furnace tuyere in the blast furnace.The pulverized coal combustion rate test was conducted and the unburned carbon residue was collected. The unburned carbon was analyzed by SEM,and the thermal weight-differential thermal analysis was used to analyze the coal by La2 O3.The results show that the combustion rate of pulverized coal is obviously improved after adding La2 O3.When the amount of La2 O3 is 1.5%,the burning rate of pulverized coal is increased by 12.33%.At this time,the average particle size of unburned carbon residue is larger than that of unburned carbon residue of raw coal.The average particle size is reduced by 14.5 μm and the appearance is extremely irregular.La2 O3 forms transient metal oxide La3+( CO-)3 on the surface of pulverized coal fixed carbon,weakens the bridge bond between carbon molecular structural units,improves the reaction rate of pulverized coal particles,promotes the early release of volatiles,and significantly improves coal. The combustion reactivity of the powder particles improves the combustion efficiency of the coal powder.
引文
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[2]夏云凯,李功民.我国动力煤干选技术现状及展望[J].洁净煤技术,2017,23(6):17-25.
[3]刘建航.我国燃煤工业锅炉现状及分析[J].洁净煤技术,2017,23(4):107-113.
[4] HEDDEN K,WILHELM A.Catalytic effects of inorganic substances on reactivity and ignition temperature of solid fuels[J]. Industrial and Engineering Chemistry Research,1980,3(2):142-147.
[5]付亚清,张建良,胡正文,等.Fe2O3对生物质焦燃烧特性的影响[J].煤质技术,2013(1):52-55.
[6]许莹,胡宾生.CeO2和La2O3对高炉喷吹煤粉燃烧过程的影响[J].稀土,2005(2):56-58.
[7]许莹,窦玉博.稀土氧化物在高炉喷吹煤粉助燃催化剂中的应用及机制分析[J].中国稀土学报,2009,27(5):635-636.
[8]张建良,杨天钧,张曦东,等.一种高炉喷煤模拟实验装置:CN201258335[P].2009-06-17.
[9]陈路,周志杰,刘鑫,等.煤快速热解焦的微观结构对其气化活性的影响[J].燃料化学学报,2012,40(6):650-652.
[10]张建良,龚必侠,张曦东.高炉喷吹煤粉添加剂热重实验研究[J].过程工程学报,2010,10(2):245-248.
[11] ZHANG Shengfu,BAI Chenguang,WEN Liangying,et al. Gasparticle flow and combustion characteristics of pulverized coal injection in blast furnace raceway[J].Journal of Iron and Steel Research International,2010,17(10):9-10.
[12]李燕江,吕庆,白瑞国,等.CeO2催化强化高炉喷吹煤粉燃烧机制[J].钢铁研究学报,2016,28(7):8-12.
[13]郭崇涛.煤化学[M].北京:化学工业出版社,1992.
[14]曹丽琼.燃煤催化剂对煤炭燃烧性能的影响[J].化工管理,2015(9):194-195.