激光诱导煤粉等离子体的特性研究

本文研究了煤粉形态对于激光诱导煤粉等离子体特性的影响,以指导应用激光感生击穿光谱进行煤质测量时最佳样品形态的选择.建立了一套激光诱导击穿光谱的实验台架,对同一煤种的4个不同粒径范围的粉状样品进行激光激发与光谱分析,利用钙原子不同跃迁能级发射谱线的强度分布计算了0.3～0.5μs区间内的等离子体温度,并依据谱线Stark展宽与电子密度的关系得到了等离子体的电子密度.再对激发不同粒径煤粉样品产生的等离子体温度与电子密度进行了对比.实验证明,煤粉粒径越小,等离子体温度越高且电子密度越大,也即样品的等离子化程度越高,越有利于煤中元素的定量分析.

STUDY ON THE PROPERTY OF LASER-INDUCED PLASMA OF PULVERIZED COAL

An investigation in the impact of the coal characteristic on property of laser induced pulverized coal plasma was conducted,which aimed to find the suitable size of pulverized coal for ultimate analysis of coal.Four coal samples with different particle size were analyzed at an experiment setup of sufficient parameters,and the spectral lines of calcium ions were used to analysis the plasma temperature together with the distribution of spectrum intensity of different lines.Also the electron density was calculated by its relation to the Stark broadening of spectrum.Comparing the plasma temperature and electron density produced by focusing laser pulse into coal samples with different particle size,the result shows that the higher temperature and denser electron density presented in the sample with smaller particle size,that is,an higher degree of ionization is easily obtained in the smaller size sample,which is good for the ultimate analysis of coal.