Abstract
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.
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