Chen Bingyu, Liu Guijian, Sun Ruoyu
CAS Key Laboratory of Crust-Mantle Materials and Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, 230026, Anhui, China.
State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, The Chinese Academy of Sciences, Xi'an, 710075, Shaanxi, China.
Arch Environ Contam Toxicol. 2016 May;70(4):724-33. doi: 10.1007/s00244-016-0267-7. Epub 2016 Feb 16.
A better understanding on the partitioning behavior of mercury (Hg) during coal combustion in large-scale coal-fired power plants is fundamental for drafting Hg-emission control regulations. Two large coal-fired utility boilers, equipped with electrostatic precipitators (ESPs) and a wet flue gas desulfurization (WFGD) system, respectively, in coal energy-dominant Huainan City, China, were selected to investigate the distribution and fate of Hg during coal combustion. In three sampling campaigns, we found that Hg in bottom ash was severely depleted with a relative enrichment (RE) index <7 %, whereas the RE index for fly ash (9-54%) was comparatively higher and variable. Extremely high Hg was concentrated in gypsum (≤4500 ng/g), which is produced in the WFGD system. Mass balance calculation shows that the shares of Hg in bottom ash, fly ash, WFGD products (gypsum, effluents, sludge), and stack emissions were <2, 17-32, 7-22, and 54-82%, respectively. The Hg-removal efficiencies of ESPs, WFGD, and ESPs + WFGD were 17-32, 10-29, and 36-46%, respectively. The Hg-emission factor of studied boilers was in a high range of 0.24-0.29 g Hg/t coal. We estimated that Hg emissions in all Huainan coal-fired power plants varied from 1.8 Mg in 2003 to 7.3 Mg in 2010.
深入了解大型燃煤电厂煤燃烧过程中汞（Hg）的分配行为，对于制定汞排放控制法规至关重要。在中国以煤炭能源为主的淮南市，分别选取了两台配备静电除尘器（ESP）和湿法烟气脱硫（WFGD）系统的大型燃煤电站锅炉，来研究煤燃烧过程中汞的分布和去向。在三次采样活动中，我们发现底灰中的汞严重贫化，相对富集（RE）指数<7%，而飞灰的RE指数（9 - 54%）相对较高且变化较大。极高含量的汞集中在WFGD系统产生的石膏中（≤4500 ng/g）。质量平衡计算表明，汞在底灰、飞灰、WFGD产物（石膏、废水、污泥）和烟囱排放中的占比分别<2%、17 - 32%、7 - 22%和54 - 82%。ESP、WFGD以及ESP + WFGD的汞去除效率分别为17 - 32%、10 - 29%和36 - 46%。所研究锅炉的汞排放因子处于0.24 - 0.29 g Hg/t煤的较高范围内。我们估计淮南所有燃煤电厂的汞排放量在2003年为1.8 Mg，到2010年增至7.3 Mg。
Zotero 插件