Size-dependent penetration of trace elements through a utility baghouse

Combustion Aerosols: Factors Governing Their Size and Composition and Implications to Human Health

“…Other studies have shown an enrichment of the smaller particle sizes in the trace volatile elements. 21,54,60,61,66,[69][70][71][72][74][75][76][77][78][79][80][81][82][83][84] The reasons for attention to the size dependence of trace element concentration are that (1) this provides a diagnostic for the mechanism of surface deposition; (2) the enrichment of submicron particles in certain elements affects the total capture efficiency of that element in the APCDs; and (3) elemental concentrations affect the chemical speciation, which can be important for health effects.…”

“…63,78,88,148,152,179,180 Additional efforts have focused on the effectiveness of APCDs in removing these potentially toxic substances. 63,78,179,180 These studies provide the following information: Figure 12. Normalized differential particle mass distributions measured in the stack for a sample of coal-fired power plants using different burner and gas-cleaning technologies.…”

“…• Particles entering the APCD are essentially bimodal in terms of mass, with on the order of 1% of the ash consisting of submicrometer particles and the larger residual ash falling into the 1-20 µm range. 54,63,180,182 • Particles in the 0.1-0.3 µm range have the highest penetration through APCD compared with both larger and smaller particles, 63,78,179,180 so the 0.1-1 µm particles form a larger fraction of the mass distribution leaving the APCD than they do in the uncontrolled combustion emissions. 63 • The submicrometer ash is enriched in volatile elements relative to the larger particles.…”

Toxic Substances From Coal Combustion-a Comprehensive Assessment

“…Because suitable standards, offering a close matrix match to the pyrite unknowns, were not available, quantitative results were not obtained. However, the results show relative differences among the samples, when the response for trace elements is plotted as ratios vs. 32 S or 57 Fe, whose content in pyrite is assumed to be uniform. Because the ionization efficiency differs for each element, and relative sensitivity factors (a measure of ionization efficiency) for pyrite are not well known, the ratios determined cannot be used to compute concentrations using Fe or S as an internal standard.…”

“…Trace elements contained in submicron particles are of concern because the collection efficiency of electrostatic precipitators and filter bag control equipment is lower for submicron particles than for supermicron particles [10,32,33].…”