飞灰含碳量是评价锅炉燃烧效率的重要指标之一, 对其进行在线测量有助于实时进行燃烧优化调整, 从而提高整个机组的经济性和安全性。 利用螺杆式给粉机搭建飞灰颗粒流含碳量测量台架, 将脉冲激光直接作用于飞灰颗粒流, 形成等离子体, 利用激光诱导击穿光谱技术测量飞灰颗粒流中的含碳量信息。 重点研究了激光能量对飞灰颗粒流中未燃碳有效激发和测量的影响规律。 研究结果显示, 在40～130 mJ能量的脉冲激光作用下, 碳谱线强度随着激光能量的增大线性增强, 而其信噪比则先增加后趋于稳定, 无效光谱的剔除率则呈下降趋势。 本实验条件下, 激光能量在90～100 mJ之间, 可得到较强的等离子体发射信号和较优的光谱数据利用率。 因而激光能量与颗粒流的激发状态、 碳元素特征谱线强度等密切相关。 合理的激光能量有利于保证飞灰颗粒流的有效稳定激发, 并获得具有良好信噪比的等离子体光谱信号。

The fly ash particle flow was produced by a screw feeder and then ablated by a pulse laser to create plasma. The emission spectra of fly ash were detected by laser-induced breakdown spectroscopy. The present paper focused on the influence of laser energy on the measurement of unburned carbon. Seven groups of pulse laser in the range of 40 to 130 mJ were used to ablate the f1y ash particle flow．The results show that the carbon line intensity is increased linearly with the increases in laser energy, but the SNR of carbon line increases in the range of 40 to 90 mJ and then trends to saturation, while the elimination rate of false data decreases. In this experiment, laser energy ranging from 90 to 100 mJ can enhance the plasma emission signal and improve the true spectral data of fly ash particle flow. So laser energy has close correlations with the ablation of the particle flow and the carbon line intensity .Reasonable laser energy is good for the effective ablation of the fly ash particle flow to get plasma spectra signals with good SNR.