The characteristics of inorganic elements in ashes from a 1 MW CFB biomass gasification power generation plant

This paper investigated the characteristics of inorganic elements in ashes from biomass gasification power generation (BGPG) plant. The ash samples of the gasifier ash, separator ash and wet scrubber ash were collected in a 1 MW circulating fluidized bed (CFB) wood gasification power generation plant. Particle size distribution of ashes was determined by gravimetric measurement and super probe analyzer. The concentrations of trace elements and major ash-forming elements, such as As, Al, Ca, Cd, Cr, Cu, K, Mg, Na, Ni, Pb, Ti in different ashes as a function of particle size were determined by Inductive Coupled Plasma Spectrometer. The concentrations and distribution coefficient and enrichment factors of the inorganic elements in ashes were studied. X-ray fluorescence spectrometer and X-ray powder diffraction were used to provide information on the characteristics of the ashes. The results showed that most of the trace elements had an enrichment tendency in the finer size particles. A considerable amount of the ashes was residual carbon. Most of the volatile e.g. halogen elements and alkali elements existed mainly in wet scrubber ash and enriched in fly ash. Most of the Si, Ni, Pb, Zn, Cr, Cd were found in separator ash, indicating an enrichment of heavy metal elements in separator ash. K, S, Mn, Cu mainly existed in gasifier ash.