激光波长对煤激光诱导击穿光谱特性影响的试验研究

Effects of Laser Wavelength on Properties of Coal LIBS Spectrum

我国电站入炉煤种复杂多变,实时快速获取煤质成分对保障锅炉的安全、高效、低污染运行具有重大意义。将激光诱导击穿光谱(LIBS)技术应用于燃煤煤质测量,观测了不同波长激光(355,532和1 064nm)诱导产生的等离子体时间演变特性和不同电离特性元素的谱线时间特性,对比了出现屏蔽效应时的能量阈值随激光波长的变化特征,并研究了激光波长对煤LIBS光谱特性的影响规律。结果发现:使用532nm激光作为激发光源时,煤LIBS光谱具有最强的谱线信号强度,且出现等离子体屏蔽效应的能量阈值也较高,是一种较理想的激发光源,为LIBS技术在煤质测量领域的工业应用提供了实验依据。

In face of the complicated and changeable coal in Chinese power stations, the on-line measurement of coal elemental composition is extremely significant in terms of enhancing the safety and efficiency of boilers as well as lowering the waste emission during operation. In this work, laser induced breakdown spectroscopy （LIBS） was applied to coal quality measurement. Laser wavelength was changed as 355，532 and 1 064 nm to investigate the influence on coal LIBS features, including plasma time evolution and the spectral lines intensity-time characteristics of different elements. Energy threshold for shielding effect was also tested to verify how it varies with laser wavelengths. Additionally, coal LIBS spectrum was analyzed under different laser wavelengths. It has been proven by experiments that higher intensity of coal LIBS spectrum and energy threshold can be easily achieved when using laser of 532 nm, making it a fantastic energy source for coal LIBS tests. Results of these experiments serve to guide the industrial application of LIBS technology in the field of coal quality measurement.