Chen Chuanmin, Liu Songtao, Gao Yang, Liu Yongchao
School of Environmental Science & Engineering, North China Electric Power University, Baoding 071003, China.
ScientificWorldJournal. 2014 Mar 4;2014:581724. doi: 10.1155/2014/581724. eCollection 2014.
Secondary atmospheric pollutions may result from wet flue gas desulfurization (WFGD) systems caused by the reduction of Hg(2+) to Hg(0) and lead to a damping of the cobenefit mercury removal efficiency by WFGD systems. The experiment on Hg(0) reemission from limestone-gypsum WFGD slurry was carried out by changing the operating conditions such as the pH, temperature, Cl(-) concentrations, and oxygen concentrations. The partitioning behavior of mercury in the solid and liquid byproducts was also discussed. The experimental results indicated that the Hg(0) reemission rate from WFGD slurry increased as the operational temperatures and pH values increased. The Hg(0) reemission rates decreased as the O2 concentration of flue gas and Cl(-) concentration of WFGD slurry increased. The concentrations of O2 in flue gas have an evident effect on the mercury retention in the solid byproducts. The temperature and Cl(-) concentration have a slight effect on the mercury partitioning in the byproducts. No evident relation was found between mercury retention in the solid byproducts and the pH. The present findings could be valuable for industrial application of characterizing and optimizing mercury control in wet FGD systems.
二次大气污染可能源于湿法烟气脱硫（WFGD）系统中汞离子（Hg(2+)）还原为汞单质（Hg(0)）的过程，这会导致WFGD系统协同脱汞效率降低。通过改变诸如pH值、温度、氯离子（Cl(-)）浓度和氧气浓度等运行条件，开展了关于石灰石-石膏WFGD浆液中Hg(0)再排放的实验。同时还讨论了汞在固体和液体副产物中的分配行为。实验结果表明，WFGD浆液中Hg(0)的再排放率随运行温度和pH值的升高而增加。随着烟气中氧气浓度和WFGD浆液中Cl(-)浓度的增加，Hg(0)的再排放率降低。烟气中的氧气浓度对汞在固体副产物中的留存有显著影响。温度和Cl(-)浓度对汞在副产物中的分配影响较小。未发现汞在固体副产物中的留存与pH值之间存在明显关系。本研究结果对于湿法烟气脱硫系统中汞控制特性表征及优化的工业应用具有重要价值。
