燃煤电厂氮氧化物产生浓度影响因素的敏感性和相关性研究

Sensitivity and correlation analysis on influence factors of NO_x generated concentration from coal-fired power plant

燃煤电厂氮氧化物产生浓度监测是计算排放浓度的基础,要实现氮氧化物排放浓度的控制,研究其产生浓度的影响因素很重要.因此,本文选取了187组燃煤电厂的现场实测及历史实测氮氧化物数据,装机规模覆盖12～1000MW,通过敏感性分析和偏相关分析,对不同类型燃煤机组氮氧化物产生浓度的各主要影响因素进行定量分析.敏感性分析发现,采用低氮燃烧技术的发电锅炉中,影响氮氧化物产生浓度的因素依次为机组规模、空气过剩系数、机组负荷率、煤中挥发分、煤中含氮量;未采用低氮燃烧技术的发电锅炉中,影响氮氧化物产生浓度的因素依次为煤中挥发分、空气过剩系数、机组规模、机组负荷率、煤中含氮量.通过偏相关分析发现,对于采用低氮燃烧技术的发电锅炉,在置信水平为99%的情况下,氮氧化物产生浓度与机组规模呈负相关关系,偏相关系数为-0.412;与空气过剩系数呈正相关关系,偏相关系数为0.265;与煤中挥发分呈负相关关系,偏相关系数为-0.355;与机组负荷率呈正相关关系,偏相关系数为0.245;与煤中含氮量的相关性不显著.对于未采用低氮燃烧技术的发电锅炉,在置信水平为99%的情况下,氮氧化物产生浓度与机组规模呈正相关关系,偏相关系数为0.345;与空气过剩系数呈正相关关系,偏相关系数为0.325;与煤中挥发分呈负相关关系,偏相关系数为-0.543;与机组负荷率及煤中含氮量的相关性不显著.

As the emissions from coal-fired power plants are mainly determined by NOx production.it is therefore important to study factors affecting NOx generation concentration in order to control NOx emission concentration.187 sets of NOx data are selected including on-site actual measurement and collection of historical observation from coal-fired power plants with the installed capacity ranging 12~1000 MW.By sensitivity analysis and partial correlation analysis,the main influence factors of NOx generation concentration are analyzed quantitatively based on different typed coal-fired units.For boilers with LNB（low nitrogen boiler） technology,the factors affecting NOx generation concentration in order are units size,excess air coefficient,units load rate,coal volatile content and nitrogen content in the coal;for boilers without LNB technology,they are coal volatile content,excess air coefficient,units size,units load rate and nitrogen content in the coal.For boilers with LNB technology with 99% of corresponding concomitant probability,NOx generation concentration is negatively correlated with units size and coal volatile content,with the related coefficient of-0.412 and-0.355,respectively.NOx generation concentration is positively correlated with excess air coefficient and units load rate,with the related coefficient of 0.265 and 0.245,respectively.It is not markedly correlated with nitrogen content in the coal.For boilers without LNB technology with 99% of corresponding concomitant probability,it is positively interrelated with units＇ size and excess air coefficient,with the related coefficient of 0.345 and 0.325,respectively.It is negatively correlated with coal volatile content,with the related coefficient of-0.543,and is not markedly correlated with units load rate and nitrogen content in the coal.