To understand the mercury speciation and mass flow in a full-scale bituminous coal-fired power plant equipped with a selective catalytic reduction (SCR) unit, an electrostatic precipitator (ESP), and a seawater flue gas desulfurization (SWFGD) scrubber, the evolution and emission of mercury was systematically measured and analyzed. The results showed that the elemental mercury (Hg⁰) was oxidized mainly through heterogeneous oxidation, especially in SCR, which transformed 57–64% of elemental mercury (Hg⁰) to oxidized mercury (Hg²⁺). It changed the concentrations of different mercury species and then increased the Hg²⁺ removal efficiencies of SWFGD, which ranged from 67 to 82%. A total of 8.24–11.54% of mercury was adsorbed by fly ash to form particulate-bound mercury (Hg^P) and subsequently removed by the ESP. Mass flow and mass distribution of mercury indicated that most mercury was removed and retained in the SWFGD. The heterogeneous oxidation of Hg⁰ in SCR and then absorption of Hg²⁺ by SWFGD significantly enhanced the mercury removal in the studied coal-fired power plant, although a part of Hg²⁺ absorbed in SWFGD was reduced and released back to the flue gas. Hg²⁺ was a little more than Hg⁰ in the flue gas emitted to the atmosphere. In addition, the SWFGD system without limestone addition may be beneficial for decreasing the re-emission of Hg⁰. The mercury emission factor at the power plant is 4.098 g/TJ, which is lower than that at other power plants without SCR. The configuration of SCR + ESP + SWFGD enhances the co-benefit mercury control.

中文翻译：

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大型火力发电厂汞转化的质量流量分析和海水烟气脱硫对脱汞的影响

要了解配备了选择性催化还原（SCR）单元，静电除尘器（ESP）和海水烟气脱硫（SWFGD）洗涤塔的大型烟煤电厂的汞形态和质量流量，对汞的排放进行了系统的测量和分析。结果表明，元素汞（Hg ⁰）主要通过非均相氧化被氧化，特别是在SCR中，该元素将57-64％的元素汞（Hg ⁰）转化为氧化汞（Hg ²⁺）。它改变了不同汞物种的浓度，然后增加了Hg ²⁺SWFGD的去除效率介于67％至82％之间。粉煤灰吸附了总计8.24–11.54％的汞，形成了结合颗粒的汞（Hg ^P），随后被ESP去除。汞的质量流量和质量分布表明，大多数汞已被除去并保留在SWFGD中。在研究的燃煤电厂中，SCR中Hg ⁰的异质氧化然后被SWFGD吸收Hg ²⁺显着提高了除汞能力，尽管SWFGD中吸收的一部分Hg ²⁺减少了并释放回烟道气中。 。汞²⁺比汞⁰多一点在排放到大气中的烟气中。此外，不添加石灰石的SWFGD系统可能有利于减少Hg ⁰的再排放。电厂的汞排放因子为4.098 g / TJ，低于其他没有SCR的电厂的汞排放因子。SCR + ESP + SWFGD的配置可增强对汞的协同效益控制。