CeO2鈥揟iO2 Sorbents for the Removal of Elemental Mercury from Syngas

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• 作者：Jinsong Zhou ; Wenhui Hou ; Pan Qi ; Xiang Gao ; Zhongyang Luo ; Kefa Cen
• 刊名：Environmental Science & Technology
• 出版年：2013
• 出版时间：September 3, 2013
• 年：2013
• 卷：47
• 期：17
• 页码：10056-10062
• 全文大小：370K
• 年卷期：v.47,no.17(September 3, 2013)
• ISSN：1520-5851

文摘

A series of CeO₂鈥揟iO₂ (CeTi) sorbents with different CeO₂/TiO₂ mass ratios were prepared by an impregnation method and employed to remove elemental mercury (Hg⁰) in simulated syngas. The CeTi sorbents with a CeO₂/TiO₂ mass ratio of 0.2 exhibited superior Hg⁰ removal efficiency from 80 to 150 掳C, which could be ascribed to the greater amount of surface chemisorbed oxygen resulted from Ce³⁺ on the sample surface. H₂S was the most effective syngas component responsible for Hg⁰ removal. The use of 400 ppm H₂S resulted in 98% Hg⁰ removal efficiency under the experimental conditions. H₂ and CO had a negligible effect on the efficiency of Hg removal. In the presence of H₂S, a prohibitive effect of HCl and NH₃ on Hg⁰ removal was observed because of the consumption of the surface oxygen. Water vapor also inhibited Hg⁰ removal due to competitive adsorption with H₂S. Hg⁰ removal over CeTi sorbents was proposed to follow the Eley鈥揜ideal mechanism, in which active surface sulfur reacts with gas-phase Hg⁰. This large oxygen storage capacity of CeTi sorbents is quite favorable to H₂S catalytic oxidation and Hg⁰ emission control in an extremely reducing environment, such as when there is a deficiency of O₂.