飞灰未燃碳的激光诱导击穿光谱定量分析

Quantitative Analysis of Unburned Carbon in Fly Ash by Laser-induced Breakdown Spectroscopy

为了验证LIBS测量飞灰中碳含量变化的能力,本文将煤粉与飞灰按照一定比例均匀混合,得到24种含碳量不同的样品.在不同延迟时间下进行激光诱导击穿光谱实验,得到温度指标发射强度比I_(Mg1)/I_(Mg2)随延迟时间的增大而减小,纯飞灰样品的发射强度比I_(Mg1)/I_(Mg2)的数值明显大于其他混入煤粉的样品.样品中发射谱线强度比IAl/ISi1随温度指标I_(Mg1)/I_(Mg2)的增大而减小.飞灰样品加入煤粉后,对等离子体的温度变化有明显影响.同时引入多元分析的方法,将样品中C、Al、Mg、Ca、Fe等元素谱线强度与Si元素谱线强度的比值作为多元回归分析的自变量,碳元素浓度作为因变量,建立不同延迟时间下的回归方程.结果表明,采用多元分析的方法进行定量计算,根据回归模型得到的预测值与参考值之间的误差基本在9%以内.

To verify the ability of LIBS to measure the change of carbon content in fly ash,in this study, 24 samples with different carbon content were obtained by mixing pulverized coal and fly ash in a certain proportion. Spectra of these samples from LIBS were studied in different delay time. The emission intensity ratio of IMg1/IMg2 decreases with the increase of delay time. The emission intensity ratio of fly ash samples is obviously higher than that of other samples mixed with pulverized coal. The emission intensity ratio of IAl/ISi1 decreases with the increase of IMg1/IMg2. The addition of pulverized coal in the fly ash sample has a significant influence on the temperature change of plasma. By introducing the method of multivariate analysis, the ratios of spectral lines intensity of elements such as C, A1, Mg , Ca ,Fe to that of Si element were calculated as the independent variable of multivariate regression analysis, and the concentration of carbon element was taken as dependent variable, and the regression equation under different delay time was established. The results showed the reference values based on the regression model were that the errors between the predicted values and within 9 %.