燃烧过程中碱金属原位测量技术综述

Review of in-situ measurement techniques of alkali metals in combustion

准东煤、生物质等高碱燃料在燃烧过程中释放的碱金属极易导致炉膛受热面沾污、结渣,影响锅炉运行的安全性,开展燃烧过程中碱金属定量测量对优化燃烧具有重要意义。将广泛采用的碱金属原位测量技术分为主动式、被动式2类:主动式包括激光诱导荧光技术、激光诱导击穿光谱技术与吸收光谱技术,被动式包括火焰发射光谱技术与图像处理技术;详细介绍了各种测量技术的基本原理及其在工业燃烧炉膛中的应用情况。主动式的碱金属原位测量技术对火焰几乎没有干扰,燃烧过程中原子和分子的光谱状态可以用很高的时间、空间分辨率观察,对碱金属的测量精度高,已经广泛用于实验室燃烧检测研究。而被动式的碱金属原位测量技术由于装备简单、对恶劣环境的适应性强,被证明有在现实工业条件下应用的潜力。最后,总结了碱金属原位测量技术的主要设备、应用、测量组分与检测限值,并指出了当前碱金属检测技术的不足及未来发展趋势。

The alkali metals released from combustion process of high alkali fuels such as Zhundong coal and biomass are probable to cause fouling and slagging on heating surfaces of furnace and affect the operation safety.Therefore,quantitative measurement of alkali metals in combustion process is of great significance to combustion optimization.The widely used in-situ measurement techniques of alkali metals include two types:active and passive.The former includes laser-induced fluorescence,laser-induced breakdown spectroscopy and absorption spectroscopy,while the latter includes flame emission spectroscopy and image processing.The basic principles of various measurement techniques and their application in industrial furnace combustion are introduced in detail.Considerable progress has been made in in-situ measurement of alkali metals.The active measurement has almost no interference to the flame,and the spectral states of atoms and molecules in the combustion process can be observed with high temporal and spatial resolution,which has been widely used in laboratory combustion detection research with high measurement accuracy.While the passive alkali metal in-situ measurement technology has been proved to have potential application in real industrial conditions due to its advantages of simple equipment and strong adaptability to harsh environment.Finally,the main equipment,applications,components and detection limits of all kinds of technologies involved in the review are summarized,and the shortcomings and future development trends of the current detection technology of alkali metals are pointed out.