关于气相二汞在钙基湿法烟气脱硫浆系统中的吸附行毕业论文外文翻译.docx

Experimental study on the absorption behaviorsof gas phase bivalent mercury in Ca-based wetflue gas desulfurization slurry system AbstractiGas phase oxidation and catalytic oxidation of element mercury (IIg°) to bivalent mercury (Hg2)were proposed to improve the mercury removal efficiency in the wet flue gas desulfurization (WFGD) system. However, the re-emission of Hg°, generated by the reduction of absorbed Hg2, would lead to a damping of the total mercury removal efficiency. In this paper, the absorption and reduction behaviors of bivalent mercury in the Ca-based WFGD slurry were evaluated in our purpose-built device. According to our experimental results, the slurry chemistry (such as CaS〇3 content, SO42 , Cl and pH value) had a strong influence on the reduction of absorbed bivalent mercury. And the inlet concentrations of SO2 and 〇2 contribute little to the mercury absorption. Within the typical pH value range of 4.5-5.5, about 70% of inlet bivalent mercury was converted to Hg°. The re-emission of Hg would be greatly retarded with the increase of [SO42 ] due to the formation of HgS〇4 or Hg3〇2S〇4. Moreover, it was found that Cl would also inhibit the reduction of bivalent mercury through the ligands reactions between Cl and Hgz . Introduction Mercury, due to its persistence, bio-accumulation and neurological toxicity, had received considerable attention from environmental engineers and environmental protecting institutions [1]. According to the conservative estimation of Environmental Protection Agency (EPA), the exposure reference dose of 0.1 fig (mercury)/kg (body weight)/day was justified to protect against harmful neurological effects during fetal development and early childhood [2]. Coal combustion was considered as the largest source of anthropogenic mercury emission. Mercury existed in the flue gas mainly in three forms: element mercury (HgO), oxidized mercury (Hg2一）and particle-bound mercury (Hg (P)) [3]. In the combustion zone, the mercury in the coa