改性燃煤飞灰吸附氧化脱汞机理研究进展

发布时间：2018-02-08 19:31

本文关键词： 汞污染吸附剂燃煤飞灰氧化表面活性卤化改性　出处：《化工进展》2017年11期 　论文类型：期刊论文

【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。
[Abstract]:Elemental mercury is the difficult point of mercury pollution prevention in coal-fired power plants. The research and development of high-efficient and inexpensive mercury adsorbent has been regarded as the key direction of scientific and technological research. The mercury removal potential of fly ash from coal combustion is strong after modified by halides, and the cost is low. However, the mechanism of adsorption and oxidation of Hg0 must be studied. In this paper, the research progress of fly ash as mercury removal material in mercury pollution control of coal-fired flue gas at home and abroad is systematically reviewed, and the physical and chemical characteristics and components of flue gas are discussed. The effect of halogen and other factors on the removal of mercury from fly ash was discussed. It was pointed out that the heterogeneous reaction on the surface active sites of unburned carbon and inorganic mineral components was the key of Hg0 oxidation removal. The advantages and disadvantages of carbon residue and magnetic beads as carrier materials were analyzed. The effects of different modifiers and modification methods on the direct modification of fly ash were discussed. The adsorption and oxidation mechanism of HBr modified fly ash to Hg0 was summarized. It is suggested that the study of bonding characteristics and reaction kinetics of Hg0 on fly ash surface should be regarded as the research direction in the future by combining quantum chemistry theory with macroscopic experimental study.
【作者单位】：神华集团有限责任公司;
【基金】：国家科技支撑计划项目(2015BAA05B02)
【分类号】：X773

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