• 论文
主办单位:煤炭科学研究总院有限公司、中国煤炭学会学术期刊工作委员会
混煤燃烧过程中汞释放特性
  • Title

    Release characteristics of mercury during the combustion of mixed coal

  • 作者

    王淑勤 刘丽凤 尹大琪

  • Author

    WANG Shuqin,LIU Lifeng,YIN Daqi

  • 单位

    华北电力大学环境科学与工程系华北电力大学河北省电厂烟气多污染物控制重点实验室 华北电力大学区域能源系统优化教育部重点实验

  • Organization
    Department of Environmental Science and Engineering,North China Electric Power University,Hebei Key Lab of Power Plant Flue Gas Multi-Pollutants Control,North China Electric Power University,Key Laboratory of Regional Energy System Optimization of Ministry of Education,North China Electric Power University,
  • 摘要

    为了提高高-低硫混煤的燃烧特性,在混煤中加入添加剂(生物质、钙基添加剂、催化剂)后在管式炉中进行脱汞性能实验。采用微波辅助溶胶凝胶法制备了纯二氧化钛(TiO2)和钕掺二氧化钛(Nd-TiO2)。为探究脱汞机理,对催化剂进行了比表面积(BET)、X-射线衍射(XRD)、电镜扫描(SEM)、X-射线光电子能谱(XPS)和电子能谱(EDS)表征分析。对生物质进行了傅里叶红外光谱(FT-IR)分析,对确定方案样品进行了热重(TG-DTG)分析。脱汞性能实验结果表明:混煤选择低硫煤A和高硫煤C按质量比为4.5∶5.5进行混匀,在混煤中同时加入生物质油菜秸秆(煤油质量比为7∶3)、钙基添加剂氧化钙(CaO)(Ca/S物质的量比为2∶3)、催化剂Nd-TiO2(Nd-TiO2的质量=煤的质量×8%、1% Nd、500 ℃),脱汞效率为72.7%,比混煤中只加油菜秸秆和氧化钙的脱汞效率提高了14.1%,比混煤中只加入油菜秸秆的脱汞效率提高295%。表征分析结果表明:稀土离子Nd3+掺入二氧化钛在一定程度上造成晶体表面发生微小畸变但未改变其晶型结构,催化剂的比表面积从12.20 m2/g增加至66.79 m2/g,增大了近4.5倍,提高了TiO2的催化活性。油菜秸秆对Hg0的脱除主要集中在表面的羟基官能团的吸附作用和含氧官能团的氧化作用,同时,油菜秸秆中含有大量的碱性化合物Fe2O3等可以催化氧化Hg0;氧化钙降低烟气中SO2的浓度,解除了高浓度SO2对Hg0的抑制作用;Nd-TiO2协同油菜秸秆及氧化钙促进汞的去除。



  • Abstract

    In order to improve the combustion characteristics of the mixed coal with high and low sulfur,the experiment of mercury removal is carried out in a tubular furnace after adding additives (biomass,calcium based additives,catalyst) to the mixed coal.Pure titanium dioxide (TiO2) and neodymium doped titanium dioxide (NdTiO2) are prepared by microwaveassisted solgel method.To explore the mechanism of mercury removal,the catalysts are characterized by BrunauerEmmettTellerbet (BET),Xray Diffraction (XRD),Scanning Electron Microscope (SEM),Xray Photoelectron Spectroscopy (XPS) and Energy Dispersive Spectrometer (EDS).The biomasses are analyzed by Fourier infrared spectrum (FTIR).Thermogravimetric analysis (TG-DTG) is carried out on the samples of the determined scheme.The experimental results of mercury removal performance show that the mixture of low sulfur coal A and high sulfur coal C are mixed according to the mass ratio of 4.5∶5.5.The efficiency of mercury removal is 72.7% when the biomass rape straw (the mass ratio of coal to rape straw is 7∶3),calcium based additive CaO (the molar ratio of Ca to S is 2.3),catalyst Nd-TiO2 (the mass ratio of Nd-TiO2to coal is 8%,mass doping content of Nd in TiO2 is 1%,calcination temperature is 500 ℃) are added to the mixed coal,which is 14.1% higher than the efficiency of mercury removal of adding rape straw and calcium oxide in the mixed coal,and 29.5% higher than the efficiency of mercury removal of adding rape straw in the mixed coal.The results of characterization analysis show that the rare earth ion Nd3+ doped titanium dioxide causes slight distortion of the crystal surface to some extent,but does not change its crystal structure.The specific surface area of the catalyst increases from 12.20 m2/g to 66.79 m2/g,which increases nearly 4.5 times,and improves the catalytic activity of TiO2.The results of characterization analysis also show that the removal of Hg0 by rape straw mainly focus on the adsorption of hydroxyl groups on its surface and the oxidation of oxygencontaining functional groups on its surface.At the same time,rape straw contains a large number of basic compounds,such as Fe2O3,which can catalyze the oxidation of Hg0CaO reduces the concentration of SO2in flue gas and eliminates the inhibitory effect of high concentration SO2on Hg0.The doping of rare earth neodymium increases the specific surface area of titanium dioxide,improves the redox ability of titanium dioxide.Nd-TiO2 promotes mercury removal in combination with rape straw and CaO


  • 关键词

    ​高-低硫混煤脱汞燃料添加剂油菜秸秆氧化钙Nd-TiO2

  • KeyWords

    high-low sulphur mixed coal,mercury removal,fuel additives,rape straw,CaO,Nd-TiO2

  • 文章目录

    1 实验部分

        1.1 催化剂的制备

        1.2 生物质和煤的元素分析和工业分析

        1.3 实验方法

        1.4 表征方法

    2 结果与讨论

        2.1 添加剂的脱汞性能评价

        2.2 添加剂的表征分析

        2.3 添加剂与煤共燃后混煤灰的分析

        2.4 脱汞机理初探

    3 结论

  • 引用格式
    王淑勤,刘丽凤,尹大琪. 混煤燃烧过程中汞释放特性[J]. 煤炭学报,2020,45(11):3921-3929.
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