Catalytic Oxidation and Stabilized Adsorption of Elemental Mercury from Coal-Derived Fuel Gas

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• 作者：He Zhang ; Jiantao Zhao ; Yitian Fang ; Jiejie Huang ; Yang Wang
• 刊名：Energy & Fuels
• 出版年：2012
• 出版时间：March 15, 2012
• 年：2012
• 卷：26
• 期：3
• 页码：1629-1637
• 全文大小：461K
• 年卷期：v.26,no.3(March 15, 2012)
• ISSN：1520-5029

文摘

The aim of this study is to develop an efficient process for the stabilized removal of elemental mercury (Hg⁰) from coal-derived fuel gas by the aid of the catalytic oxidation of Hg⁰ over activated carbon (AC). The experiments were performed in the temperature range of 120鈥?40 掳C with simulated coal-derived gases containing varying concentrations of CO, H₂, CO₂, H₂O, and H₂S. O₂ was introduced to promote the oxidation reaction between H₂S and Hg⁰ over the AC sorbent to form mercury sulfide (HgS). The results indicated that the Hg⁰ removal capacity of AC could be dramatically improved in the presence of both H₂S and O₂. The presence of O₂ was indispensable for the efficient and stable removal of Hg⁰ from H₂S-containing fuel gas. The high temperature and high content of reducing gases, such as CO and H₂, may inhibit the oxidation reaction and decrease the Hg⁰ removal efficiency, whereas the high content of H₂O can promote Hg⁰ removal. On the basis of thermodynamic analysis, as well as the temperature-programmed decomposition (TPD) and X-ray photoelectron spectroscopy (XPS) characterization of the sorbents, it is suggested that the partial oxidation of H₂S with O₂ to active sulfur may contribute to the stabilized removal of Hg⁰ by the reaction of active sulfur with Hg⁰ to form HgS.