Removal of Gas-Phase Elemental Mercury in Flue Gas by Inorganic Chemically Promoted Natural Mineral Sorbents

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• 作者：Feng Ding ; Yongchun Zhao ; Liangliang Mi ; Hailong Li ; Yang Li ; Junying Zhang
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2012
• 出版时间：February 22, 2012
• 年：2012
• 卷：51
• 期：7
• 页码：3039-3047
• 全文大小：386K
• 年卷期：v.51,no.7(February 22, 2012)
• ISSN：1520-5045

文摘

A variety of natural mineral sorbents were synthesized and tested on a lab-scale fixed-bed system to evaluate mercury removal efficiencies under a simulated flue gas condition that contains 84% N₂, 4% O₂, and 12% CO₂ in volume fraction. Three types of natural minerals, bentonite (Ben), mordenite (Mor), and attapulgite (Atp), were selected as raw sorbents, and several chemical promoters, such as CuCl₂, NaClO₃, KBr, and KI, were employed to enhance mercury removal abilities of the raw sorbents. The physical-chemical characteristics of these minerals were analyzed by an X-ray diffractometer (XRD), an accelerated surface area and porosimeter (ASAP) using the N₂ isotherm adsorption/desorption method, and X-ray fluorescence (XRF) spectrometry. The mercury concentration was detected continuously using a VM3000 online mercury analyzer. The results showed that CuCl₂-impregnated Atp (Cu-Atp) and CuCl₂-impregnated Ben (Cu-Ben) presented about 90% average Hg⁰ removal efficiencies at 120 掳C, respectively. In addition, as the temperature increased, the removal efficiencies decreased. Although NaClO₃-impregnated Atp showed an average Hg⁰ removal efficiency more than 90% at 120 掳C, its performance was limited by the testing temperature, and that was probably due to the high iron oxide content in Atp. For the KI-impregnated sorbents, high mercury removal efficiencies could be observed, and the efficiencies increased steadily with the temperature increased from 70 to 150 掳C. The three natural minerals presented poor adsorption abilities for bromine, which resulted in the disappointing mercury removal efficiencies. Generally, Cu-Atp, Cu-Ben, and KI-impregnated sorbents were promising cost-effective mercury sorbents.