Mercury Re-Emission in Flue Gas Multipollutants Simultaneous Absorption System

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• 作者：Yue Liu ; Qingfeng Wang ; Rongjun Mei ; Haiqiang Wang ; Xiaole Weng ; Zhongbiao Wu
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：December 2, 2014
• 年：2014
• 卷：48
• 期：23
• 页码：14025-14030
• 全文大小：397K
• ISSN：1520-5851

文摘

Recently, simultaneous removal of SO₂, NO_x and oxidized mercury in wet flue gas desulfurization (WFGD) scrubber has become a research focus. Mercury re-emission in traditional WFGD system has been widely reported due to the reduction of oxidized mercury by sulfite ions. However, in multipollutants simultaneous absorption system, the formation of a large quantity of nitrate and nitrite ions as NO_x absorption might also affect the reduction of oxidized mercury in the aqueous absorbent. As such, this paper studied the effects of nitrate and nitrite ions on mercury re-emission and its related mechanism. Experimental results revealed that the nitrate ions had neglected effect on mercury re-emission while the nitrite ions could greatly change the mercury re-emission behaviors. The nitrite ions could initially improve the Hg⁰-emission through the decomposition of HgSO₃NO₂^{鈥?/sup>, but with a further increase in the concentration, they would then inhibit the reduction of bivalent mercury owing to the formation of Hg-nitrite complex [Hg(NO₂)_x2-x]. In addition, the subsequent addition of Cl鈥?/sup> could further suppress the Hg0 emission, where the formation of a stable Hg-SO₃鈥揘O₂鈥揅l complex was assumed to be the main reason for such strong inhibition effect.}