贫煤O_2/CO_2气氛下燃烧时内在矿物质对SO_2和NO_x排放特性的影响

Effect of mineral matter on emissions of SO_2 and NO_x during combustion of lean coal in O_2/CO_2 atmosphere

利用管式炉反应器在550-1 000℃对长治贫煤和脱矿物质煤分别在空气和O_2/CO_2气氛进行了燃烧实验。利用XRF、XRD等分析手段,对煤样的基本性能进行了分析表征,并采用热分析仪(TG-DTG)以及傅里叶红外气体分析仪(AntarisIGS)对贫煤燃烧过程中的燃烧特性和SO_2和NO_x释放规律进行了研究。结果表明,与原煤相比,脱矿物质煤的着火温度和燃烬温度有所降低;O_2/CO_2气氛下,原煤和脱矿物质煤的着火温度和燃烬温度都升高,说明当O_2浓度为20%时,空气气氛比O_2/CO_2气氛更易于着火和燃烬。此外,与长治原煤相比,脱矿物质煤在相同条件下燃烧时SO_2的释放量明显提高,而NO_x的释放量却有所降低。O_2/CO_2气氛下原煤燃烧时SO_2浓度比空气气氛下的要高,而脱矿物质煤燃烧时释放的SO_2浓度明显比空气气氛下的低;O_2/CO_2气氛下原煤和脱矿物质煤燃烧时释放的NOx浓度比空气气氛下燃烧时释放的NO_x浓度要低。

Combustion experiments of Changzhi coal at 550-1 000 ℃ were conducted in a tube furnace reactor in air and O2/CO2,respectively. The XRF,XRD etc. were employed to study the characteristics of raw coal and its demineralized coal. Effects of mineral matter in coal on combustion characteristics and release of SO2 and NOx during combustion were investigated using TG-DTG and Antaris-IGS. The results show that ignition and burnout temperature of the demineralized coal are lower than those of raw coal. In O2/CO2 the ignition and burnout temperature of raw coal and the demineralized coal are all higher. This shows that when oxygen concentration is20%,the coals are easier to ignite and burnout in air. Besides that,SO2 emission of the demineralized coal is higher than that of raw coal; while NOx emission is opposite. For raw coal,SO2 emission is higher when combusted in O2/CO2; while for the demineralized coal,it is opposite. During combustion in O2/CO2,NOx emission is always lower whether for the raw or the demineralized coal.