燃烧温度对煤中汞析出特性及形态分布的影响

发布时间：2018-03-30 14:28

  本文选题：煤　切入点：燃烧温度　出处：《化工进展》2017年05期

【摘要】：在管式炉实验装置上研究了燃烧温度对燃煤汞析出特性的影响,利用在线烟气分析仪和EPA Method 26A湿化学法对燃煤烟气中O_2/SO_2/NO/CO/HCl/Cl_2等进行同步定量分析,探讨不同燃烧温度下烟气组分的变化及其在烟气降温过程中对汞形态迁移转化的影响规律。结果表明:在高温燃烧条件(≥750℃)下,煤中汞基本全部逸出,析出率≥97.9%,且随燃烧温度升高而递增;基于氧量分析,煤中汞的析出在挥发分燃烧阶段即开始发生;随着燃烧温度的升高,烟气中元素态汞(Hg0)份额逐渐降低,而氧化态汞(Hg~(2+))份额相应增大,900℃时接近50%;燃烧温度对烟气中各组分浓度影响较大,随温度升高,烟气中NO、HCl及Cl_2呈现不同程度的上升趋势,SO_2含量基本持平,而CO含量逐渐降低;对痕量元素汞而言,NO、HCl及Cl_2通过直接或间接氧化作用在烟气降温过程中促进Hg0向Hg~(2+)转化,烟气中还原性气体组分CO对Hg0的氧化有一定抑制作用,SO_2对汞形态分布的影响则不甚明显。
[Abstract]:The effect of combustion temperature on the mercury emission from coal combustion was studied in a tube furnace experimental device. The simultaneous quantitative analysis of O_2/SO_2/NO/CO/HCl/Cl_2 in coal-fired flue gas was carried out by on-line flue gas analyzer and EPA Method 26A wet chemical method.The changes of flue gas components at different combustion temperatures and their effects on the migration and transformation of mercury species in the process of flue gas cooling were discussed.The results show that under the condition of high temperature combustion (鈮，

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