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采用二级稀释采样方法对1台电厂煤粉炉、1台电厂CFB锅炉和2台工业层燃炉配备的WFGD前后烟气中PM_(2.5)进行现场采样。采用ELPI分析PM_(2.5)的数量及质量浓度粒径分布;通过SEM分析PM_(2.5)的显微结构,通过XRF、ICP-OES和离子色谱法分别对PM_(2.5)中次量、痕量元素及水溶性离子含量进行测定。研究结果表明,相比于WFGD前,煤粉炉和CFB锅炉WFGD后PM_(2.5)质量浓度减少,而层燃炉WFGD后PM_(2.5)质量浓度增加。WFGD后PM_(2.5)中存在大量块状、层状、片状、细小柱状和球形颗粒聚合体的结构,浆液成分及脱硫产物的附着会使PM_(2.5)的外观形貌特征发生显著变化。脱硫后由于脱硫浆液的参与,PM_(2.5)中Ca、S及相应Ca~(2+)、SO_4~(2-)含量显著增加,Si和Al的含量下降;气相的As、Se和Hg也会发生不同的化学变化从而进入PM_(2.5)。湿法脱硫过程中浆液会捕集烟气中颗粒物,但脱硫浆液成分及脱硫产物会经由干化作用直接形成颗粒或与原有颗粒经碰撞聚合形成新颗粒。
The PM_ (2.5) of WFGD before and after the flue gas equipped with 1 power plant, 1 power plant CFB boiler and 2 industrial furnaces were sampled by two-stage dilution sampling method. The particle size distribution of PM_ (2.5) and its mass concentration were analyzed by ELPI. The microstructure of PM_ (2.5) was analyzed by SEM. The amount of PM_ (2.5) and the amount of PM_ (2.5) were measured by XRF, ICP-OES and ion chromatography. Elements and water-soluble ion content were measured. The results show that the mass concentration of PM 2.5 decreases after WFGD and the mass concentration of PM 2.5 in WFGD layer furnace increases compared with that before WFGD. The structure, the composition of the slurry and the adhesion of the desulfurization products of PM_ (2.5) in PM_ (2.5) after WFGD greatly changed the appearance and appearance of PM_ (2.5). After desulfurization, the content of Ca, S and corresponding Ca ~ (2 +) and SO_4 ~ (2-) in PM_ (2.5) increased remarkably and the contents of Si and Al decreased due to the desulfurization slurry. As, Se and Hg Different chemical changes occur to PM_ (2.5). During the wet desulfurization process, the slurry will capture the particulate matter in the flue gas, but the desulfurization slurry components and desulfurization products will directly form particles through the drying or agglomeration with the original particles to form new particles.