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利用横向塞曼效应技术对烟气中的二氧化硫(SO_2)、二氧化氮(NO_2)等干扰气体进行背景校正。采用基于塞曼效应的汞监测系统测量得到烟气经过湿法脱硫(WFGD)处理系统前后烟气中元素汞(Hg~0)的平均质量浓度分别为0.36μg·m~(-3)和11.08μg·m~(-3),脱硫系统处理后烟气中Hg~0浓度显著升高。经分析,烟气中约99%的SO_2被脱硫浆液吸收,生成足量亚硫酸盐,亚硫酸盐与Hg~(2+)发生还原反应释放出Hg~0;浆液pH值的变化加速Hg~(2+)还原反应并释放Hg~0。利用WFGD系统协同脱汞可能导致烟气Hg~0排放浓度升高。Hg~0排放浓度与烟气中其他成分的浓度均具有一定的相关性,这与理论分析一致,表明横向塞曼原子吸收法可以有效去除SO_2、NO_x等气体的干扰,验证了应用横向塞曼原子吸收法检测烟气汞含量的准确性与可行性。
The lateral Zeeman effect technique is used to background correction the interference gases such as sulfur dioxide (SO 2) and nitrogen dioxide (NO 2) in flue gas. The average mass concentrations of elemental mercury (Hg ~ 0) in the flue gas before and after wet FGD (WFGD) treatment were measured by a mercury monitoring system based on the Zeeman effect and were respectively 0.36 μg · m -3 and 11.08 μg · m -3, the Hg ~ 0 concentration in flue gas after desulfurization system was significantly increased. After analysis, about 99% of the SO2 in the flue gas is absorbed by the desulfurization slurry to generate a sufficient amount of sulfite, and the reduction reaction between the sulfite and the Hg2 + releases Hg ~ 0; the change of the pH of the slurry accelerates Hg ~ (2+) reduction reaction and release Hg ~ 0. The synergetic mercury removal by WFGD system may result in the increase of Hg ~ 0 emission concentration. Hg ~ 0 emission concentration has certain relevance with the concentration of other components in flue gas, which is consistent with the theoretical analysis, indicating that the transverse Zeeman atomic absorption method can effectively remove SO 2, NO_x and other gas interference, verifying the application of transverse Zeeman Accuracy and Feasibility of Detecting Mercury Content in Flue Gas by Atomic Absorption Spectrometry.