燃煤烟气污染物控制装置协同脱汞特性研究

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Abstract The Ontario Hydro Method (OHM) was applied to determine the mercury speciation and concentration in the flue gas emitted from a 100MW boiler system.Mercury speciation transformation and removal characteristics of selective catalytic reduction (SCR) system,electrostatic precipitators (ESP) and wet flue gas desulfurization (WFGD) had been obtained.Temperature programmed decomposition (TPD),Scanning electron microscope (SEM) and X ray fluorescence (XRF) were used to investigate the adsorption characteristic of mercury by fly ashes and thermal stability after adsorption.The results show that the overall mercury (Hg^T) removal efficiencies over SCR + ESP + WFGD combination were 92.83% and 81.66% under 75% MCR and 85% MCR,respectively.The oxidation of element mercury (Hg⁰) by SCR catalyst was greatly promoted by the chlorine (Cl) content in coal and 96.18% Hg⁰ was oxidized to oxidized mercury (Hg²⁺) by SCR when the Cl concentration in burned-coal contained 500mg/kg.Hg^P could be effectively removed by ESP,removal efficiencies with 12.73% of Hg⁰ and 27.79% of Hg²⁺ were observed.Unburned carbon and metal oxides (Al₂O₃,Fe₂O₃) were the main components of ESP fly ash to adsorb gaseous mercury.HgCl₂,HgS (red),and HgO were the main mercury compounds in the ash after adsorption which would decompose when the temperature reached 190 degrees.The average removal efficiencies of Hg²⁺ by WFGD were 91.10%.Meanwhile,the phenomenon of mercury re-emission due to part of Hg²⁺ was reduced to Hg⁰ in WFGD was found.

Key words： flue gas air pollution control devices mercury species removal characteristics mercury re-emission

Received: 27 July 2017

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	ZHENG Yi-wu
	DUAN Yu-feng
	TANG Hong-jian
	LI Chun-feng
	LIU Shuai
	CHEN Ming-ming

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ZHENG Yi-wu,DUAN Yu-feng,TANG Hong-jian等. Characteristics of the existing air pollutant control devices on Hg synergistic removal in a coal-fired power plant[J]. CHINA ENVIRONMENTAL SCIENCECE, 2018, 38(3): 862-870.

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http://www.zghjkx.com.cn/EN/ OR http://www.zghjkx.com.cn/EN/Y2018/V38/I3/862

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