摘要
为提高无烟煤燃烧效率和降低NOx的排放,提出借助循环流化床在低空气当量比下燃烧的技术将无烟煤粉预热到800℃以上再进入到下行燃烧室中燃烧的新工艺。在小型实验台上对预热后无烟煤粉的氮氧化物排放特性进行了实验研究。热态实验以阳泉无烟煤为燃料,实验台由提供高温预热燃料的循环流化床和用于预热燃料燃烧的下行燃烧室组成。实验结果表明,预热过程中约有36.9%的煤氮被还原为N2。随着还原区空气当量比和过量空气系数的增加,NOx的排放增加;随着煤粉在还原区停留时间的增加,NOx的排放减少。煤粉预热技术和分级燃烧技术相结合能有效降低无烟煤粉燃烧中NOx的排放。实验中,预热后无烟煤粉的燃烧效率最高能达到97.5%。
A new technique of pulverized anthracite combustion was proposed to improve combustion efficiency and reduce NOx emission. On a pilot scale test rig, pulverized anthracite was heated to the temperature higher than 800 ℃ in a circulating fluidized bed with partial combustion under low air equivalence ratio and then combusted in a down-fired combustor. NOx emission of the preheated pulverized Yangquan anthracite combustion was studied. The experimental results show that about 36.9% coal-nitrogen has been reduced to N2 during the preheating process, NOx emission decreases with the increase in the residence time of pulverized coal in the reducing zone, and increases when the air equivalence ratio in the reducing zone and excess air ratio increases. It is also revealed that the co-exiting of air-staging combustion and anthracite coal preheating is effective to reduce nitrogen oxide emission for pulverized anthracite coal combustion, and the combustion efficiency can reach 97.5%.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2014年第11期1748-1754,共7页
Proceedings of the CSEE
关键词
循环流化床
预热
无烟煤
燃烧
氮氧化物排放
circulating fluidized bed
preheat
anthracite
combustion
NOx emission
