Trace Elements Partitioning during Coal Combustion in Fluidized Bed under O2/CO2 Atmosphere
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.
Trace elements O2/CO2 combustion Fluidized bed Partitioning Temperature
Haixin Li Changsui Zhao Cai Liang Lunbo Duan Huichao Chen
School of Energy and Environment,Southeast University,Nanjing 210096,China
国际会议
The 7th International Symposium on Coal Combustion(第七届国际煤燃烧学术会议)
哈尔滨
英文
247-252
2011-07-19（万方平台首次上网日期，不代表论文的发表时间）