Mobility and enrichment of trace elements in a coal-fired circulating fluidized bed boiler
-
摘要: 对天津市某电厂循环流化床(CFB)锅炉燃用的原煤及燃烧产物底灰、飞灰、细飞灰(≤50 μm)进行痕量元素含量的测定,分析了Be、Zn、Hg、V、Cr、Mn、Co、Ni、Cu、As、Se、Cd、Pb 13种痕量元素在燃烧过程中的迁移行为,揭示了痕量元素在CFB锅炉中的分配、富集特性。结果表明,CFB锅炉中,较低的炉温对于痕量元素的迁移富集产生了较大的影响。由相对富集系数得知,Be、V、Co、Se在底灰中耗散,在飞灰中富集,Zn、Mn倾向于在底灰中富集,元素Cd、Pb、Ni、Cu挥发性较强,在底灰和飞灰中均是耗散。As受钙氧化物影响,挥发性表现并不明显。Hg在底灰和飞灰中相对富集系数均很低,表明Hg在整个燃烧过程中以气态形式排放;Hg、As、Se、V、Cr、Mn、Co、Ni、Cu、Zn、Pb均有向小颗粒物中富集的趋势。根据相对富集系数以及研究的13种元素在低温CFB锅炉中的迁移行为,将这些元素分为三类:A类(ER<0.1),主要是以气态形式排放元素Hg;B类(0.1<ER≤0.85),较易挥发元素As、Be、Ni、Cu、Se、Cd、Pb、Co、V;C类(ER>0.85),主要残留在固体产物中元素Zn、Mn、Cr。Abstract: Some hazardous trace elements in coal, bottom ash, fly ash and fine fly ash from a circulating fluidized bed (CFB) boiler in a power plant were examined. The distribution, enrichment and partitioning behavior of Be, Zn, Hg, V, Cr, Mn, Co, Ni, Cu, As, Se, Cd and Pb were analyzed. The results show that the distribution and enrichment characteristics of trace elements are greatly affected by the temperature of CFB. According to the relative enrichment factor (ER), Be, V, Co and Se trend toward fly ash; Zn and Mn show a tendency into bottom ash. Some volatile trace elements like Cd,Pb,Ni and Cu show low enrichment in both bottom ash and fly ash. The element of As is affected by calcium oxide, and its volatility is not obvious. Hg is more likely discharged with flue gas. Hg, As, Se, V, Cr, Mn, Co, Ni, Cu, Zn and Pb all have an enrichment tendency toward fine particles. On the basis of ER and behaviors of the 13 trace elements in CFB boiler, these elements are divided into 3 categories: A(ER<0.1), Hg mainly volatilizes into the atmosphere; B(0.1<ER≤0.85), As, Be, Ni, Cu, Se, Cd, Pb, Co and V are more easily volatilization; C(ER>0.85), Zn, Mn and Cr mostly stay in solid residues.
-
A study of hazardous air pollutant emission from electric utility steam generating units[J]. U.S. Government Printing Office: Washington, DC, 1998. SPEARS D A, MARTINEZ-TARRAZONA M R. Trace elements in combustion residues from a UK power station[J]. Fuel, 2004, 83(17/18): 2265-2270. HUANG W H, JIN B S, ZHONG Z P, XIAO R, TANG Z Y. Trace elements (Mn, Cr, Pb, Se、Zn, Cd and Hg) in emission from a pulverized coal boiler[J]. Fuel Process Technol, 2004, 86(1): 23-32. VEJAHATI F, XU Z, GUPTA R. Trace elements in coal: Associations with coal and minerals and their behavior during coal utilization-a review[J]. Fuel, 2010, 89(4): 904-911. 郑剑铭, 周劲松, 何胜, 骆仲泱.燃煤电厂汞排放对周边环境的影响[J].化工学报, 2009, 12(60): 3104-3111. (ZHENG Jian-ming, ZHOU Jin-song, HE Sheng, LUO Zhong-yang. Environmental impact of mercury emission from a coal-fired power plant[J]. CIESC Journal, 2009, 12(60): 3104-3111.) IZQUIERDO M, QUEROL X. Leaching behavior of elements from coal combustion fly ash: An overview[J]. Int J Coal Geol, 2012, 94: 54-66. ROY B, CHOO W L, BHATTACHARYA S. Prediction of distribution of trace elements under oxy-fuel combustion condition using Victorian brown coals[J], Fuel, 2012, in press. CLEMENS A H,DAMIANO L F,GONG D, MATHESON T W. Partitioning behavior of some toxic volatile elements during stoker and fluidized bed combustion of alkaline subbituminous coal[J]. Fuel, 1999, 78(12): 1379-1385. DAS A K, CHAKRABORTY R, GUARDIA M, CERVERA M L, GOSWAMI D. ICP-MS multielement determination in fly ash after microwave-assisted digestion of samples[J]. Talanta, 2001, 54(5): 975-981. 王珲, 宋蔷, 姚强, 陈昌和, 俞非漉. 微波消解与ICP-OES/ICP-MS测定飞灰中的多种元素[J]. 光谱实验室, 2012, 29(1): 525-528. (WANG Hui, SONG Qiang, YAO Qiang, CHEN Chang-he, YU Fei-lu. The determination of multiple elements in fly ash with Microwave digestion and ICP-OES/ICP-MS[J]. Chinese Journal of Spectroscopy Laboratory, 2012, 29(1): 525-528.) WANG J, NAKAZATO T, SAKANISHI K. Microwave digestion with HNO3/H2O2 mixture at high temperatures for determination of trace elements in coal by ICP-OES and ICP-MS[J]. Anal Chim Acta, 2004, 514(1): 115-124. 徐文东, 曾荣树, 叶大年, QUEROL X. 电厂煤燃烧后元素硒的分布及对环境的贡献[J].环境科学, 2005, 26(2): 64-68. (XU Wen-dong, ZEN Rong-shu, YE Da-nian, QUEROL X. Distributions and environmental impacts of Selenium in wastes of coal from a power plant[J]. Environmental Science, 2005, 26(2): 64-68.) QUEROL X, FERNHNDEZ-TURIEL J L, LOPEZ-SOLER A. Trace elements in coal and their behavior during combustion in a large power station[J]. Fuel, 1995, 74(3): 331-343. 任德贻, 赵峰华, 代世峰, 张军营, 雒昆利. 煤的微量元素地球化学[M]. 北京: 科学出版社, 2002: 82-83. (REN De-yi, ZHAO Feng-hua, DAI Shi-feng, ZHANG Jun-ying, LUO Kun-li. Trace elements geochemistry in coal[M]. Beijing: Science Press, 2002: 82-83.) MEIJ R. Trace element behavior in coal-fired power plants[J]. Fuel Process Technol, 1994, 39(1): 199-217. PEDERSEN J A, OTTOSEN L M, VILLUMSEN A. Electrodialytic removal of heavy metals from different fly ashes influence of heavy metal speciation in the ashes[J]. J Hazard Mater, 2003, 100(1): 65-78. BHANGARE R C, AJMAL P Y, SAHU S K, PANDIT G G, PURANIK V D. Distribution of trace elements in coal and combustion residues from five thermal power plants in India[J]. Int J Coal Geol, 2011, 86(4): 349-356. 岳勇, 姚强, 宋蔷, 李水清, 王珲. 不同煤燃烧源排放的PM10形态及重金属分布的对比研究[J]. 中国电机工程学报, 2007, 27(35): 33-38. (YUE Yong, YAO Qiang, SONG Qiang, LI Shui-qing, Wang Hui. Comparative study on PM10 microstructure and heavy metals distribution in emissions of coal combustion sources[J]. Proceedings of the CSEE, 2007, 27(35): 33-38.) 张娟, 陆继东, 余亮英, 王世杰, 张步庭. 煤中痕量元素在低温燃烧下的分布规律[J]. 工程热物理学报, 2003, 24(3): 531-533. (ZHANG Juan, LU Ji-dong, YU Liang-ying, WANG Shi-jie, ZHANG Bu-ting. Distribution of trace elements in coal combustion with low temperature[J]. Journal of Engineering Thermophysics, 2003, 24(3): 531-533.)
点击查看大图
计量
- 文章访问数: 1652
- HTML全文浏览量: 19
- PDF下载量: 635
- 被引次数: 0