基于火焰光谱的准东煤旋风燃烧过程中碱金属检测

Research on alkali metal measurement during the cyclone combustion process of Zhundong coal based on flame spectrum

我国新疆准东地区高碱煤储量丰富,但在燃烧利用过程中Na、K等碱金属以气相形式释放到烟气中会导致锅炉换热面积灰、结渣、腐蚀等,开展炉内气相碱金属释放的在线检测对于解决上述问题具有一定的指导意义。基于火焰自发射光谱法研制了1套便携式火焰中气相碱金属浓度检测系统,使用该系统对液态排渣旋风锅炉高碱煤燃烧火焰进行在线检测,得到不同测点的火焰温度、气相Na质量浓度和波段热辐射能,同时使用X射线荧光光谱(X-Ray Fluorescence Spectrometer,XRF)分析了灰渣样。结果表明:炉内气相Na质量浓度分布不均匀,燃烧哈密煤和神华煤的两渣室火焰平均温度分别为1415和1436℃,气相Na质量浓度分别为40.0和25.3 mg/m^(3)。气相Na质量浓度和波段热辐射能大小反映了炉内燃烧状态,同时在线检测结果与飞灰和液渣成分分析结果具有一定关联性,火焰气相Na质量浓度增加时,飞灰和液渣中Na质量浓度均增大,但更多的是向飞灰中迁移。

The reserves of high alkali coal are abundant in the Zhundong area of Xinjiang,but in the process of its combustion and utilization,the release of alkali metals such as Na and K into the flue gas in the form of gaseous phase will cause ash deposition,slagging,and corrosion,etc.on the heat exchange surface of the boiler.The on-line detection of the alkali metal release in the gas phase has certain guiding significance for solving the above problems.A portable system for detecting the concentration of gaseous alkali metals in the flame was developed based on flame spontaneous emission spectrum.Using this system,the on-line detection of high alkali coal combustion flame in liquid slag removal cyclone boiler was carried out.The flame temperature,gas phase Na concentration and band thermal radiation energy at different measuring points were obtained,and X-Ray Fluorescence Spectrometer(XRF)was used to analyze the ash and liquid slag samples,simultaneously.The results show that the gas phase Na mass concentration in the furnace is unevenly distributed.The average flame temperatures of the two slag chambers burning Hami coal and Shenhua coal are 1415 and 1436℃,respectively,and the gas phase Na mass concentrations are 40.0 mg/m^(3)and 25.3 mg/m^(3),respectively.The gas-phase Na concentration and band thermal radiation energy can reflect the combustion state in the furnace,and the measurement results have a certain correlation with the composition analysis results of fly ash and liquid slag.The Na mass concentration in fly ash and liquid slag increases,but more migrated to the fly ash.