改性燃煤飞灰吸附氧化脱汞机理研究进展

doi:10.16085/j.issn.1000-6613.2016-2410

摘要/Abstract

摘要： 元素汞是燃煤电站汞污染防治工作的难点，研究开发高效价廉的汞吸附剂已被作为科技攻关重点方向。燃煤飞灰经卤化物改性后脱汞潜力强、成本低，但必须研究掌握其吸附氧化Hg⁰的作用机制。本文系统综述了飞灰作为脱汞材料在国内外燃煤烟气汞污染控制方面的研究进展。论述了物化特性、烟气组分、卤素等因素对飞灰脱汞性能的影响，指出未燃尽炭和无机矿物组分表面活性位上的非均相反应是Hg⁰氧化脱除的关键。分析了残炭和磁珠作为载体材料的优缺点，并讨论了不同改性剂和改性方法对飞灰直接改性的影响。总结了HBr改性飞灰对Hg⁰的吸附氧化机理，并提出利用量子化学理论与宏观实验研究相结合的方式探索Hg⁰在飞灰表面上的成键特征及反应动力学特性应作为今后的研究方向。

关键词: 汞污染, 吸附剂, 燃煤飞灰, 氧化, 表面活性, 卤化改性

Abstract: It is difficult to control the mercury pollution in coal-fired power plant, especially for elemental mercury. Thus, the development of mercury sorbent with high efficiency and low cost has been scientific and technological focus. Coal-fired fly ash modified with halide has low price and strong potential for mercury removal. However,the adsorption and oxidation mechanism of Hg⁰ on modified fly ash is unclear and still needs further study. This review systematically summarized the current state of knowledge associated with fly ash used as mercury sorbent on controlling flue gas mercury pollution. Then,the mercury removal behaviors on various factors were discussed, including physicochemical characteristics, flue gas components and halogen. The heterogeneous reaction on the surface active sites of unburned carbon and inorganic components was the key point of Hg⁰ oxidative removal. Furthermore, the merits and faults of unburned carbon and magnetosphere acted as carrier were analyzed. In addition, the influences of modifying agent and preparation method on direct modification of fly ash and the adsorption mechanisms on HBr-modified fly ash were discussed. Finally,future research directions were proposed,involving exploring the characteristics for Hg⁰ binding on the organic and inorganic portion of fly ash,and studying the reaction dynamic behaviors of Hg⁰ on the surface of multi-components through combination of quantum chemistry theory and macroscopic experimental investigation.

Key words: mercury pollution, sorbents, coal-fired fly ash, oxidation, surface reactivity, halogenated modification

中图分类号:

X511
X705

顾永正, 王树民. 改性燃煤飞灰吸附氧化脱汞机理研究进展[J]. 化工进展, 2017, 36(11): 4257-4264.

GU Yongzheng, WANG Shumin. Research progress of mercury adsorption and oxidation mechanism on modified coal-fired fly ash[J]. Chemical Industry and Engineering Progress, 2017, 36(11): 4257-4264.

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