O_2/CO_2气氛下煤粉燃烧NO排放特性

NO Emission Characteristics of Pulverized Coal Combustion in O_2/CO_2 Atmosphere

在沉降炉上对O_2/CO_2气氛下超细煤粉(0~20,μm)、大粒径煤粉(70~100,μm)以及二者混合煤粉NO的生成特性进行了研究,结合红外光谱分析研究了煤焦表面含氧官能团与NO生成之间的关系.结果表明:随着挥发分析出燃烧和煤焦燃烧的进行,NO沿炉子长度方向分布呈现为"M"型.入口气氛中氧体积分数提高,NO生成速度加快,入口附近NO体积分数峰值提高,炉子出口附近NO体积分数并未同步提高.煤粉粒径分布不同,沿炉子方向NO分布曲线形态不同,NO峰值出现位置发生改变.入口氧体积分数不同,煤焦表面含氧官能团生成规律不同,煤焦表面含氧官能团增加,有利于降低NO的生成.

NO emission characteristics during pulverized coal combustion in an O2/CO2atmosphere were studied for micro-pulverized coal(0-20,μm),large-size coal(70-100,μm)and mixed-size coal of the above two coals with an equal mass fraction.The relationship between oxygen-containing functional groups and NO emission was analyzed by FTIR analysis.Results show that the NO emission curve along the furnace length was displayed as“Mtype”in coal devolatilization and char burning processes.With the increase of the inlet oxygen mole fraction,the NO concentration increases rapidly and reaches a peak in a shorter time.While the NO concentration near the furnace outlet does not shown the same trend.The coal size has a great effect on the NO emission.The peak of“Mtype”curve and the location where the peak occurs change with the coal size.In the coal burning process,the oxygen-containing functional groups change with the inlet oxygen mole fraction.A lower NO emission was observed when more oxygen-containing functional groups were generated.