循环流化床煤燃烧产物中微量元素分布特征

On Trace Elements in Circulating Fluidized Bed Combustion of Coal

利用清华大学小型循环流化床对黔西南高硫煤进行燃烧实验 ,研究循环流化床燃烧过程中煤中微量元素在燃烧产物中的重新配置和对环境的影响 ,以及固硫添加剂对煤中部分有害微量元素排放的控制作用 .结果表明 ,循环流化床灰中 ,As、Sb、Pb、Cu、Be与Zn等在细粒灰中富集 ,Pb、As、Sb、Se、Th、Ni与Cr等在磁性灰中富集 .除尘器后烟道灰中富集Zn、As、P、Ni、Cr、Mo、Be、Pb、Th、Hg与F等 ,而Nb、Rb与Zr等明显亏损 .在煤中加入固硫添加剂燃烧后比较发现 ,As、Se、Sb与Zn等在细粒流化床灰中富集能力降低 ,As、Se、Li、Be、Mo、Cr、Co与Ni等在除尘器后烟道灰中含量降低 ,烟道喷淋水中Cu、Zn、Cr、Pb、Co、Ni、F与Se等的含量降低 .循环流化床燃烧过程中 ,固硫添加剂不仅降低SO2 的排放 ,而且对部分有害微量元素 (As、Se、Be、Cr、Co、Ni、Pb、Zn与F等 )

For the better understanding of the partitioning behaviors of trace elements and their emissions with or without additive during circulating fluidized bed (CFB) combustion of coal, the coal was burned in a small CFB combustor. Coal samples, including CFB ash, magnetic ash in CFB ash, ash from chimney after dust remover and spraying water from chimney, were collected and analyzed using ICP-AES, AFS, INAA,ICS and CV-AAS. The experimental result shows that the trace elements (As, Sb, Pb, Cu, Be, Zn) are enriched substantially in the fine particles of CFB ash, and Pb, As, Sb, Se, Th, Ni, Cr are enriched in the magnetic ash in CFB ash.In the ash from chimney after dust remover, Zn, As, P, Ni, Cr, Mo, Be, Pb, Th, Hg, F are enriched while Nb, Rb, Zr are obvious deficient. With sulphur capture additive, the contents of As, Se, Sb, Zn in the fine particles of CFB ash decrease, and the contents of As, Se, Li, Be, Mo, Cr, Co, Ni in the ash from chimney after dust remover and the contents of Cu, Zn, Cr, Pb, Co, Ni, F, and Se in the spraying water from chimney decrease. Additive can control the emission of some potentially hazardous trace elements.