利用均相氧化機制模擬汞傳輸與排放之研究

Study Mercury Transformation and Emission by Using Homogeneous Hg Oxidation Mechanism

楊彬洲(Pin-Chou Yang)

指導教授 ： 林傑

國立屏東科技大學/工學院/環境工程與科學系所/碩士(2010年)

https://doi.org/10.6346/NPUST.2010.00006

摘要

廢棄物焚化爐及燃煤電廠為主要汞污染源，微粒態汞(HgP)及氧化態汞(Hg2+)通常會被集塵裝置捕捉，而元素汞(Hg0)是相對惰性、非反應性、非水溶性，且在高溫下容易揮發，所以很困難被捕捉，如應用適當的處理程序將元素汞轉化為氧化態形式時，汞的移除效率將會提升。本研究利用化學動力模式模擬14個汞氧化反應機制，探討不同汞濃度及HCl、Cl2濃度對中間產物與生成物之影響。主要研究結果如下：（1）燃煤電廠及垃圾焚化爐汞氧化模擬結果得到相當的一致性。（2）在充足的氯物種濃度條件下，Hg0以相當穩定的速率消耗及轉化，至800°K附近轉化反應結束。（3）中間物種HgO與HgCl在500~820°K區間生成、消長、轉化，生成濃度最高點發生在726°K。（4）汞完全轉化成HgCl2之反應溫度在820°K以後達到穩定（飽和）。在720°K之前HgCl2的生成主要來自Hg與HCl、Cl2反應轉化，而720°K之後，中間物種HgCl、HgO與HCl、Cl2進一步反應轉化為主要貢獻者。（5）以Widmer的8個汞氧化機制與Xu的14個汞氧化機制模擬比較，由數據集及趨勢圖均看不出明顯的差異，Xu提出之中間物種HgO生成機制對汞氧化的重要性在本研究中並未明顯表現。

關鍵字

汞 ； 均相 ； 氧化機制 ； 化學動力模式

並列摘要

The emission of mercury by waste incinerators and coal-fired power plants were the main parts from anthropogenic activities. The particulate bound mercury (HgP) and oxidized mercury (Hg2+) were usually trapped by ash collection devices. Conversely, elemental mercury (Hg0) was difficulted to capture because of its non-reactivity. The removal of mercury was enhanced when Hg0 was converted to its oxidized form. This research utilized Chemkin Model to simulate Widmer and Xu mercury oxidation mechanisms to realize the effects of HCl and Cl2 affecting the mercury oxidation. The predicted results were as followings: (1) The simulation result was quite consistency between coal-fired power plant and incinerator. (2) Hg0 fully transformed into its oxidized form near 800°K with steadily consumed and transformed rate. (3) The intermediate species, HgO and HgCl, synchronously grew and then transformed fully between 500~820°K and the maximum concentration occurred at 726°K. (4) Hg0 totally transformed into HgCl2 took place at 820°K. (5) The important effect of the intermediate species HgO which proposed by Xu could not be observed obviously in this research.

並列關鍵字

Mercury ； Homogeneous ； Oxidation Mechanism ； Chemkin

參考文獻

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