Biography:

In the past Wayne S. Seames has collaborated on articles with William P. Linak. One of their most recent publications is Assessing the solubility of inorganic compounds from size-segregated coal fly ash aerosol impactor samples. Which was published in journal Journal of Aerosol Science.

More information about Wayne S. Seames research including statistics on their citations can be found on their Copernicus Academic profile page.

Wayne S. Seames's Articles: (3)

Assessing the solubility of inorganic compounds from size-segregated coal fly ash aerosol impactor samples

AbstractAn important issue for the coal-fired utility industry is the release of heavy metals contained in fly ash. Before companies can plan emission minimization strategies for these compounds, they must have an accurate means of predicting the forms of occurrence in the waste stream and the solubility of these forms into the surrounding environment. The EPA's Toxicity Characterization Leaching Protocol (TCLP) Method 1310 was modified to allow the testing of inorganic compounds contained on greased impactor membranes. The modified method was used to explore the solubility of four trace elements from five different types of coal fly ash. For most coals, selenium has limited solubility at pH 5.0 and is not expected to significantly impact groundwater sources. Arsenic, antimony, and cobalt are typically partially soluble at pH 5.0 and a portion of these metals may migrate out of the ash particles. Further, these metals show increased solubility at pH 2.9.

On trimodal particle size distributions in fly ash from pulverized-coal combustion

Combustion-generated fine particles, defined as those with aerodynamic diameters less than 2.5 μm, have come under increased regulatory scrutiny because of suspected links to adverse human health effects. Whereas classical theories regarding coal combustion suggest that mechanisms of ash vaporization and fragmentation lead to bimodal ash particle size distributions (PSDs), this paper presents experimental results supporting other existing hypotheses that three distinct ash modes may be more appropriate. This paper focuses on the existence and generality of a central mode, between approximately 0.7 and 3.0 μm diameter. This central mode is presumably caused by fragmentation mechanisms, but is still important from a health perspective, because a large portion is contained within the 2.5 μm particle size fraction. Presented here are experimental results from two different laboratory combustors and one industrial boiler, all burning pulverized coals. Use of a variety of particle-sampling and size classification methods, including electrical mobility, time-of-flight, and inertial (low-pressure impaction) methods, confirms that the central mode is not an artifact of the particle-sampling and -sizing methods used. Results from the combustion of 10 different coals consistently show that this central mode is significant for both high-and low-rank coals. Size-segregated elemental distributions of calcium, iron, and aluminum provide additional insight into mechanisms of formation of each mode. Field tests show that the central mode can be the major contributor to fine particle emissions leaving an electrostatic precipitator (ESP). The new experimental results presented here are interpreted in the light of complementary existing data and available theories from the literature.

Regimes of association of arsenic and selenium during pulverized coal combustion

AbstractA suite of six coals, of widely differing As, Se, Ca, Fe, and sulfur contents, was burned under self-sustaining conditions in a 17 kW downflow laboratory combustor. Size segregated ash-laden aerosol samples were isokinetically withdrawn and collected on a Berner low pressure impactor. Correlations between trace element concentration (As or Se) and that of major elements (as functions of particle size) were then used to infer chemical associations between trace metals and Ca and/or Fe, and how these depended on sulfur. These baseline data led to formation of the following hypotheses, namely:(1)dominant As and Se partitioning mechanisms depend on the availability of Ca and/or Fe active sites for surface reaction;(2)increasing combustion temperature increases the availability of active cation sites, and increases partitioning of As and Se to fly ash by surface reaction;(3)sulfur competes with these surface reactions, decreasing As and Se partitioning to fly ash surfaces.These hypotheses were tested by manipulating the As, Se, Ca, Fe, and S contents for various coals by doping. Temperature was adjusted in order to achieve comparisons of different coals and different coal constituents at similar thermal conditions, through O2 and CO2 addition, as required. These results confirmed the hypotheses above, and allowed an association regime map to be constructed. This map shows that both As and Se associate with Fe and Ca, provided active sites are available. Se reacts preferentially with Fe over Ca when both are available while As reactions with both Fe and Ca are comparable. Sulfur can prevent association of both As and Se, by preferentially reacting with active sites, especially those on Fe. When sufficient sites are not available, the release of vapor-phase As and Se species is promoted.

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