生物质气化发电厂灰渣中微量元素的分布与富集规律

采用电感耦合等离子体发射光谱仪，研究了生物质气化发电厂灰渣中元素As、Al、Br、Ca、Cd、Cl、Cr、Cu、F、Fe、Ga、K、Mg、Mn、Na、Ni、P、Pb、S、Si、Sr、Ti、Zn在气化器底灰、淋洗器灰和旋风分离器灰中的质量分数，并分析了这些元素在不同粒径3种灰渣中的分布规律。结果表明，大部分极易挥发的元素，如卤族元素、碱金属元素主要在淋洗器中存在，表明了它们在飞灰颗粒中的富集。旋风分离器灰在灰渣中所占比例为10%左右，以粗灰为主，灰中Fe、Si、Ni、Pb、Zn、Cr、Cd为多；表明了此灰中重金属元素积累。在气化炉底灰中以K、S、Mn、Cu为主。元素随颗粒物粒径大小和元素性质的不同，呈现不同的富集规律。

Distribution and enrichment of trace elements in ashes from biomass gasification power plant

The biomass gasification power generation (BGPG) technology would be one of the most advanced ways to use biomass as an clean energy source. A 1MW circulating fluidized bed (CFB) wood waste gasification power generation plant was built and put into operation. The main existing problems during operations are fouling, slagging and corrosion, which are related to the characteristics of ash. A sound understanding of the characteristics of ashes can promote the design of BGPG and the assessment of the environmental impact of biomass utility. Therefore, the characteristics of ashes from biomass gasification power generation plant were investigated. The concentration, distribution and enrichment of the trace elements, As, Al, Br, Ca, Cd, Cl, Cr, Cu, F, Fe, Ga, K, Mg, Mn, Na, Ni, P, Pb, S, Si, Sr, Ti, Zn in the gasifier bottom ash, cyclone separator ash and wet scrubber ash were determined by Inductive Coupled Plasma Spectrometer (ICP-AES). X-ray fluorescence (XRF) spectrometer was used to determine the ash compositions based on the weight percent of oxide. The distribution of trace elements in different sizes of ash particles was also examined. The particle size distribution for >50 μm ash presents a double peak curve, while the particle size distribution for ≤50 μm ash presents a single peak curve. The results show that the large part of ash is residual carbon, and most of the trace elements have an enrichment tendency in the small size particles. Most of volatile matter, e.g. halogen elements and alkali elements, mainly exists in the wet scrubber ash and enriches in fly ash. Most of Fe, Si, Ni, Pb, Zn, Cr, Cd elements are found in the separator ash, indicating an enrichment of heavy metal elements in separator ash. The trace elements such as K, S, Mn, Cu are mainly found in the gasifier bottom ash.