激光能量对粉煤灰未燃碳测量的影响  

Impact of Laser Energy on Measurement of Fly Ash Carbon Content

作　　者：姚顺春[1] 陆继东[1,2] 谢承利[2] 李捷[2] 潘圣华[1] 何泽雄[1] 

机构地区：[1]华南理工大学电力学院,广东广州510640 [2]华中科技大学煤燃烧国家重点实验室,湖北武汉430074

出　　处：《光谱学与光谱分析》2009年第8期2025-2029,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(50576029)资助

摘　　要：搭建了基于激光诱导击穿光谱技术的成分分析应用研究台架,应用于粉煤灰未燃碳的检测,考察不同能量的脉冲激光烧蚀粉煤灰样品时的等离子体特性。使用多通道光纤光谱仪和CCD探测器对激光烧蚀形成的等离子体发射信号进行分光和探测。分析碳谱线强度、等离子体温度和电子密度随激光能量变化的趋势,掌握激光能量对粉煤灰未燃碳测量的影响规律。研究结果显示,随着激光能量的增大,碳谱线强度、等离子体温度和电子密度均先增大后减小,空气击穿明显增强。随后碳谱线强度的变化趋于平缓并开始下降。合适的激光能量可以增强等离子体发射信号,并避免强烈空气击穿的不利影响,有助于提高测量精度。A laser induced breakdown spectroscopy-based apparatus for the analysis of element, employing a 532 nm laser and a multi-channel optical spectrometer with a non-intensified CCD array, has been built and tested. It was applied to analyze the carbon content of coal fly ash. Seven groups of pulse laser in the range of 35 to 98 mJ were used to ablate the fly ash samples. The electron densities and plasma temperatures with different laser energy were determined, and the influence of laser energy on the intensity of analysis carbon lines was also analyzed. The results show that carbon line intensity increases slowly with the increase in laser energy in the range of 35 to 46 mJ, and increases fast in the range of 46 to 78 mJ, then trends to saturation and has a little drop. At the same time, air breakdown has increased significantly, and has an obvious effect on sample plasma. Furtbermore, the electron density and plasma temperature increase with the laser energy until 78 mJ and then begin to decrease. It indicates that a proper laser energy can enhance the plasma emission signal, and avoid the negative impact of air breakdown that prevent the pulse laser from reaching the surface of sample and ablating it. In this experiment situation, the measurement accuracy of the carbon line can be improved.

关 键 词：激光诱导击穿光谱 激光能量 煤灰未燃碳 谱线强度 电子密度 空气击穿 

分 类 号：O657.3[理学—分析化学]