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Experiments were conducted to investigate the effects of temperature and O2/CO2 atmosphere on trace elements (Cr, Mn, Co, Ni, Cd, Pb, Hg, As, Se) partitioning during combustion of Xuzhou bituminous coal in a 6 kWth fluidized bed. Inductively coupled plasma mass spectrometry (ICP-MS) and atomic fluorescence spectrometry (AFS) were used to determine trace elements contents in raw coal, bottom ash, fly ash and flue gas. The results indicate that with bed temperature increase, the relative enrichment of all the trace elements except Cr in bottom ash decreases suggesting that their volatility is enhanced. The relative enrichments of hardly volatile elements, like Cr and Mn in fly ash increase with bed temperature increase while those of partially volatile and highly volatile elements in fly ash are opposite. The relative enrichments of trace elements except Cr and Mn in fly ash are higher than those in bottom ash. Increasing bed temperature promotes elements like As, Se and Hg to migrate to vapor phase, Mn to migrate to fly ash and Cr to migrate to both bottom ash and fly ash. 21%O2/79%CO2 atmosphere improves the volatility of Cr, Mn, Co, Se and their migration to fly ash, while restrains the volatility of As, Ni, Pb. It has little effect on the volatility of Hg but improves its migration to fly ash.
Mass balance ratio was also calculated to observe trace elements distribution in bottom ash, fly ash and flue gas. There is no much difference in trace elements distribution between the two atmospheres. It can be seen that the trace elements proportion in fly ash is much greater, and more than 40% of Hg is distributed in the gas phase. Most of Hg and Se volatilize during combustion. The mass balance ratios are 87 ~ 129% which is considered acceptable.
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Xu M, Zheng C. Overview of trace elements research in coal combustion process. Proc CSEE. 2001;21(10):33–8.
Duan L, Zhao C. Latest development of CFB O 2/CO 2 combustion technology. J Power Eng. 2008;28(4):605–11.
Huang Y, Jin B. Trace elements (Mn, Cr, Pb, Se, Zn, Cd and Hg) in emissions from a pulverized coal boiler. Fuel Process Technol. 2004;86(1):23–32. CrossRef
Hunag Y, Jin B. The relationship between occurrence of trace elements and gasification temperature. Proc CSEE. 2006;26(4):10–5.
Senior C, Helble J. Emissions of mercury, trace elements, and fine particles from stationary combustion sources. Fuel Process Technol. 2000;65:263–88. CrossRef
Lu H, Chen H. Occurrence and volatilization behavior of Pb, Cd, Cr in Yima coal during fluidized-bed pyrolysis. Fuel. 2004;83(1):39–45. CrossRef
Yan R, Gauthier D. Volatility and chemistry of trace elements in a coal combustor. Fuel. 2001;80(15):2217–26. CrossRef
Li Z, Clemens A. Partitioning behaviour of trace elements in a stoker-fired combustion unit: an example using bituminous coals from the greymouth coalfield (cretaceous), New Zealand. Int J Coal Geol. 2005;63(1–2):98–116. CrossRef
Guo R, Yang J. The fate of As, Pb, Cd, Cr and Mn in a coal during pyrolysis. J Anal Appl Pyrolysis. 2003;70(2):555–62. CrossRef
Clarke LB. The fate of trace elements during coal combustion and gasification: an overview. Fuel. 1993;72(6):731–6. CrossRef
Meij R, Tewinkel B. Trace elements in world steam coal and their behaviour in Dutch coal-fired power stations: a review. Int J Coal Geol. 2009;77(3–4):289–93. CrossRef
Seames W, Wendt J. The partitioning of arsenic during pulverized coal combustion. Proc Combust Inst. 2000;28(2):2305–12. CrossRef
Senior C, Bool L. Pilot scale study of trace element vaporization and condensation during combustion of a pulverized sub-bituminous coal. Fuel Process Technol. 2000;63(2–3):149–65. CrossRef
Yan R, Gauthier D. Behavior of selenium in the combustion of coal or coke spiked with Se. Combust Flame. 2004;138(1–2):20–9. CrossRef
Seames W, Wendt J. Regimes of association of arsenic and selenium during pulverized coal combustion. Proc Combust Inst. 2007;31(2):2839–46. CrossRef
Jamil K, Hayashi J. Pyrolysis of a Victorian brown coal and gasification of nascent char in CO 2 atmosphere in a wire-mesh reactor. Fuel. 2004;83(7–8):833–43. CrossRef
Lu J, Chen X. Experimental study of trace element migration characteristics in an O 2/CO 2 atmosphere. J Eng Thermal Energy Power. 2009;24(5):648–51.
Li Y, Sheng C. Experimental study on distribution of trace elements in fine ash particles during O 2/CO 2 combustion of pulverized coal. J Eng Thermophys. 2008;29(7):1236–8. MATH
Huang Y, Jin B. Study on the distribution of trace elements in gasification products. Proc CSEE. 2004;24(11):208–12.
- Trace Elements Partitioning During Coal Combustion in Fluidized Bed Under O2/CO2 Atmosphere
- Springer Berlin Heidelberg