煤粉颗粒流的激光诱导击穿光谱特性及其测量方法研究

The on line analysis of coal in coal-fired power plant is an important way to optimize and adjust coal combustion, and also to save energy. The project aims to solve the key scientific issues for the direct measurement of coal particle flow by Laser-Induced Breakdown Spectroscopy (LIBS). The excitation characteristics of the coal particles in different flow state (mass flow and the diameter of the particle flow) are studied to ensure the key parameters and structure for stable exciting coal particles and effective collection the plasma. The interaction between coal particles flow and laser and its plasma characteristics are studied to reveal the interaction mechanism and the temporal and spatial evolution of plasma. The impact of key test parameters on the characteristics of laser plasma is studied, and then the different effective spectral data extraction and optimization methods are developed to obtain stable plasma spectral data. On the basis of the project study, it is expected to reveal the mechanism of the interaction between coal particles flow and laser. This work also provides a theoretical and experimental basis for the development of the online analysis technique based on LIBS which can detect multi-components of coal simultaneously.

燃煤电厂中入炉煤的在线检测是燃烧优化和调整、实现节能减排的重要途径。本项目针对激光诱导击穿光谱（Laser-Induced Breakdown Spectroscopy，LIBS）技术应用于煤粉颗粒流直接检测的关键科学问题。研究不同颗粒流流束状态（颗粒质量流量和流束直径）下煤粉颗粒的激发特性，获得可以确保煤粉颗粒流稳定激发和等离子体信号有效收集的关键参数和光学结构；研究煤粉颗粒与激光的相互作用过程和等离子体特性，揭示煤粉颗粒流与脉冲激光相互作用机制及其所产生的等离子体时空演化机制；考察关键测试参数和煤粉特性等对激光等离子体特性的影响规律，建立有效光谱数据提取和优化方法，获得稳定的煤粉颗粒流等离子体光谱数据。通过本项目的研究，可揭示脉冲激光与煤粉颗粒流的相互作用机制，掌握煤粉颗粒流的激光诱导击穿光谱特性及其测量方法，为发展基于LIBS技术的入炉煤多组分在线同步检测技术提供理论依据和实验基础。

燃煤电厂中入炉煤的在线检测是燃烧优化和调整、实现节能减排的重要途径。本项目针对激光诱导击穿光谱（Laser-Induced Breakdown Spectroscopy，LIBS）技术应用于煤粉颗粒流直接检测的关键科学问题。设计了一套自制的颗粒流约束下料口，研究了不同颗粒流流束状态（颗粒质量流量和流束直径）下煤粉颗粒的激发特性，获得了可以确保煤粉颗粒流稳定激发的流束参数。搭建了不同模式的收光系统，对比了不同模式下的多元素谱线信号的探测性能，确定了有效收集激光等离子体信号的关键参数和光学结构；研究了关键测量参数（激光波长、能量）对等离子体光谱特性（等离子体温度、电子密度和谱线强度）的影响规律，揭示了煤粉颗粒流与脉冲激光相互作用机制；详细分析了煤粉颗粒流的等离子体光谱特性，建立了基于多元素谱线的有效光谱提取方法，在此基础上发展了基于光谱归一化的谱线优化方法，提高了颗粒流直接测量的等离子体光谱数据稳定性。通过本项目的研究，掌握了煤粉颗粒流的激光诱导击穿光谱特性及其测量方法，为发展基于LIBS技术的入炉煤多组分在线同步检测技术提供了理论依据和实验基础。