SCR气氛下Ce-W/TiO<sub>2</sub>催化剂的脱硝协同脱汞特性

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Abstract

The effects of reaction temperature and flue gas composition on the denitrification and mercury removal efficiency of Ce-W/TiO₂ (Ce: W=2:1) catalysts were investigated in a fixed bed reactor. The results showed that the reaction temperature had a significant effect on the denitrification and mercury removal efficiency of Ce-W/TiO₂. In the temperature range of 280~400℃, the denitration efficiency increased as temperature increased, while the mercury removal efficiency was higher at temperature 280℃ and 360℃, with the best denitrification and mercury removal efficiency at 360℃. In the SCR atmosphere, HCl had a great effect on the oxidative removal of Hg⁰. Low concentration of HCl was also beneficial to the improvement of denitration efficiency, but excessive HCl concentration had an inhibitory effect on NO removal. The presence of SO₂ could promote the denitrification process and inhibit the oxidation of Hg⁰. The catalysts before and after the reaction were characterized by BET, XRD, SEM, TPD, XRF, NH3-TPD and other analytical methods. The results showed that Ce-W/TiO₂ had no microporous structure, and the active components CeO₂ and WO₃ were distributed on the surface of the carrier in a highly dispersed form. At 280℃, part of Hg was adsorbed on the surface of the catalyst in the form of HgCl₂. As the reaction temperature increased, the adsorption of mercury on the surface of the catalyst decreased sharply. HCl and SO₂ in SCR atmosphere could affect the acidity of catalyst surface and increase the content of Cl and S, thus, affect the denitration and mercury removal efficiency of the catalyst.

Key words： Ce-W/TiO₂ Hg⁰ removal denitrification temperature gas component

Received: 25 September 2018

PACS:

X701.7

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	Articles by authors
	GENG Xin-ze
	DUAN Yu-feng
	HU Peng
	LIU Shuai
	LIANG Cai

Cite this article:

GENG Xin-ze,DUAN Yu-feng,HU Peng等. Characteristics of denitrification and mercury removal of Ce-W/TiO₂ catalysts in SCR atmosphere[J]. CHINA ENVIRONMENTAL SCIENCECE, 2019, 39(4): 1419-1426.

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http://www.zghjkx.com.cn/EN/ OR http://www.zghjkx.com.cn/EN/Y2019/V39/I4/1419

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