W火焰锅炉低负荷条件下掺烧煤泥的数值模拟

Numerical Simulation on Burning Blended Coal Slime Under the Condition of Low Load in W-flame Boiler

随着煤炭洗选工业的快速发展,其工艺产生的废弃物——煤泥的产量明显上升,而将煤泥掺混到燃煤锅炉中进行燃烧是实现煤泥资源化处置的有效手段之一。通过现场试验与数值模拟相结合的方法,对一台W火焰锅炉在低负荷条件下无烟煤掺烧煤泥的燃烧特性进行了研究,分析了掺烧不同比例(0%、5%、10%、15%、20%、25%)煤泥炉内燃烧及排放特性。结果显示,当煤泥掺烧比例小于20%时,炉内温度水平降低,飞灰含碳量上升,NO_x排放下降;当煤泥掺混比例大于20%时,高挥发分的煤泥提前燃烧对无烟煤后期燃烧产生较大的负面影响,使得无烟煤的燃烧和燃尽过程有所推迟,且混煤燃烧不充分,NO_x排放上升。

With rapid development of coal processing industry,output of coal slime has increased obviously.It is one of effective ways to realize resourceful treatment by means of mixing the coal slime in the coal-fired boiler.Therefore,on the basis of combination of field test and numerical simulation,this paper studies combustion characteristic of the anthracite blending coal slime of one W-flame boiler under the condition of low load and analyzes furnace combustion characteristic and emission characteristic after co-firing coal slimes with different ratios of 0%,5%,10%,15%,20%and 25%.The results show as the blending combustion ratio is less than 20%,temperature level in the furnace decreases,carbon content in the fly ash increases and NO x emission reduces.While when the ratio is more than 20%,advanced combustion of the coal slime with high volatile will produce great negative influence on later combustion of the anthracite,which may delay combustion and burn-out of the anthracite and cause inadequate combustion of mixed coals and increase of NO x emission.