An investigation of mercury distribution and speciation during coal combustion
An investigation of mercury distribution and speciation during coal combustion
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DOI：
10.1016/j.fuel.2004.06.015
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发表时间：
2004-11
期刊：
影响因子：
7.4
通讯作者：
Yewen Tan;R. Mortazavi;Bob Dureau;M. Douglas
中科院分区：
文献类型：
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作者：
Yewen Tan;R. Mortazavi;Bob Dureau;M. Douglas
CETC-O的中试规模垂直燃烧研究设施（VCRF）增加了多场静电除尘器（ESP）和两级冷凝换热器（CHX®），以进一步研究燃煤电厂的综合排放控制。在VCRF上进行了一系列燃烧试验，使用三种不同的煤（烟煤、次烟煤和褐煤），以研究汞在不同VCRF位置的分布和形态。结果表明，对于烟煤，随着烟气从700 °C冷却至200°C，气相中总汞的80%以氧化形式存在，20%以元素形式存在。对于次烟煤和褐煤，元素汞是整个系统的主要形式。对沉积的灰烬样本的分析表明，氧化汞可以被富碳灰烬沉积物吸收，尽管总体而言，只有很小比例的总汞被灰烬吸收。还探索了CHX®从烟道气中去除汞的潜力。结果表明，使用湿法洗涤，CHX®能够去除98%的氧化汞。尽管元素汞在系统中并未减少，但建议使用适当的试剂氧化CHX®中的元素汞，可以使用CHX®去除氧化汞和元素汞。最后，进行了汞平衡，并在整个VCRF中获得了良好的汞平衡，验证了我们的采样程序和分析方法。
A multi-field electrostatic precipitator (ESP) and a two-stage condensing heat exchanger (CHX®) have been added to the pilot scale Vertical Combustion Research Facility (VCRF) in CETC-O to further research into integrated emissions control for coal fired power plants. A series of combustion trials were conducted on the VCRF with three different coals (bituminous, sub-bituminous and lignite) to study mercury distribution and speciation at various VCRF locations. Results showed that, with the bituminous coal, as the flue gas cools down from 700 to 200°C, 80% of total mercury in the gas phase existed in oxidized form and 20% in elemental form. For sub-bituminous and lignite coals, elemental mercury was the dominant form throughout the system. Analysis of deposited ash samples showed that oxidized mercury can be absorbed on carbon-rich ash deposits, although overall only a very small percentage of total mercury was absorbed on the ash. The potential of the CHX®at removing mercury from the flue gas was also explored. Results indicated that, using wet scrubbing, the CHX®was able to remove 98% of oxidized mercury. Though elemental mercury went through the system unabated, it is suggested that, with appropriate agent to oxidize elemental mercury in the CHX®, it is conceivable to use CHX®to remove both oxidized and elemental mercury. Finally, mercury balance was performed and good mercury balance was obtained across the VCRF, validating our sampling procedures and analysis methods.