Emission Factors of Trace Metals from Coal-Fired Power Plants

摘要

The amount of trace metals emitted per quantity of fuel consumed depends on the trace metal content of the fuel and the combustion conditions. Important for the trace metals emission factors are also the type of fly ash control systems, electrostatic precipitators (ESP) and wet scrubbers being most widely used. From among more than 60 elements contained in the fuel 16 are subject to analysis: As, Be, Cd, Co, Cr, Cu, Hg, Mo, Mn, Ni, Pb, Sb, Se, V, Zn and Zr. They are either the most toxic to the environment or appear at the highest concentrations in the fuel used. Averaged concentrations of trace metals studied and their enrichment ratios have been estimated on the basis of literature data. The mean concentrations of trace metals in different size particles emitted during coal combustion have been established knowing the enrichment behaviour of the elements analyzed. Assuming a percentage distribution of different size particles in stack dust, the concentrations of trace metals in the stack dust emitted during combustion in different boilers, (cyclone, stoker, pulverized) were calculated. Using this data, and assuming a 10% ash contents, and also assuming ESP installations with efficienty of 99%, it has been possible to calculate trace metal emissions (g/day) from a 100 MWe power plant. Data are given for bituminous, sub-bituminous and lignite and for different boilers. The same. (ERA citation 08:009043)