飞灰基吸附剂脱除烟气中Hg^(0)的研究进展  

Research Progress on Removal of Hg^(0)from Flue Gas by Fly Ash-based Adsorbents

作　　者：姚一杰 孟璐瑶 温彩媚 马宵颖[1] 段恩喆 王祥学 YAO Yijie;MENG Luyao;WEN Caimei;MA Xiaoying;DUAN Enzhe;WANG Xiangxue(Department of Environmental Science and Engineering,North China Electric Power University,Baoding 071003,China)

机构地区：[1]华北电力大学环境科学与工程系,河北保定071003

出　　处：《电力科学与工程》2024年第1期1-9,共9页Electric Power Science and Engineering

基　　金：国家自然科学基金资助项目(U2067215);河北省自然科学基金资助项目(B2019502059)。

摘　　要：与其他脱汞方法相比,利用飞灰脱除Hg^(0)能降低脱除成本、实现以废治废。目前飞灰脱汞技术在工业应用中存在脱汞效率较低的问题,所以通过深入研究来提高其应用水平具有实际意义。归纳了飞灰结构和成分(有机、无机)对Hg^(0)脱除的影响机制。从提高脱汞效率角度,梳理了4种主流的飞灰改性方法:1)卤化物浸渍改性。卤化物在飞灰表面生成Br^(*)或与飞灰中未燃烧碳反应生成C-Br以氧化Hg^(0)。改性剂中的金属阳离子以加速电荷转移、降低反应能垒的方式来促进Hg^(0)的脱除。2)机械化学改性。该方法的制备工艺简单、成本低。飞灰经机械研磨使粒径减小后,无定形相及吸附氧含量增加。研磨后未燃烧碳充分暴露,卤化点位增加,加速了C-Br氧化Hg^(0)的进程。3)过渡金属改性磁珠。经过渡金属改性磁珠的磁性增强,可循环利用,使吸附剂表面引入新的Hg^(0)氧化位点(如C-O基团、Cl^(*))。4)低温等离子体改性。飞灰经低温等离子体处理后,吸附剂表面活性等离子体(如O、Cl等离子体)含量及官能团(C=O基团和酯基)含量增加,促进了Hg^(0)的吸附。进一步探究了复杂烟气组分对飞灰基吸附剂脱汞效率的影响,并对改性飞灰的脱汞性能及适用条件进行了评价。基于当前的研究进展,建议用磁性金属硫化物对飞灰进行机械化学改性来制备脱汞剂。Compared with other mercury removal methods,the removal of Hg^(0)by fly ash can reduce the removal cost and realize waste treatment.At present,the mercury removal efficiency of fly ash in industrial application is low,so it is of practical significance to improve its application level through in-depth study.The effect mechanism of fly ash structure and composition(organic and inorganic)on the removal of Hg^(0)was organized.From the perspective of improving mercury removal efficiency,four main methods of fly ash modification were summarized:1)Halide impregnation modification.The halides formed Br^(*)on the surface of fly ash or reacted with the unburned carbon in fly ash to form C-Br to oxidize Hg^(0).The metal cations in the modifier promoted the removal of Hg^(0)by accelerating the charge transfer and reducing the reaction energy barrier.2)Mechanochemical modification.The preparation process was simple and the cost was low.After mechanical grinding,the partical size decreased,and the amorphous phase and adsorbed oxygen content increased.After grinding,the unburned carbon was fully exposed and the halogenated point increased,which accelerated the process of Hg^(0)oxidation by C-Br.3)Transition metal modified magnetospheres.The transition metal modified magnetospheres were enhanced and could be recycled,and new Hg^(0)oxidation sites(such as C-O Group,Cl^(*))were introduced on the surface of the adsorbent.4)Non-thermal plasma modification.After non-thermal plasma modification,the content of surface active plasma(such as O,Cl plasma)and functional group(C=O group and ester group)increased,which promoted the adsorption of Hg^(0).The effect of complex flue gas components on mercury removal efficiency of fly ash based adsorbent was further investigated,and the mercury removal performance and applicable conditions of modified fly ash were evaluated.Based on the current research progress,is was proposed to prepare fly ash-based mercury removal agents by mechanochemical modification of fly ash with magnetic metal sulphide

关 键 词：烟气脱汞 飞灰 未燃烧碳 改性飞灰 烟气组分 

分 类 号：TK09[动力工程及工程热物理] X511[环境科学与工程—环境工程]