The *34S and *13C distribution in a mined coal, the pulverized coal fired into the boiler, and the coal combustion by-products, demonstrated that there is some fractionation of sulfur and carbon isotopes as a result of the combustion and ashcollection process. Overall, the changes in coal composition are indications of the spatial chemical differences in the coal and its heterogeneity at the mine. Coal at the mine shows a striking, stratigraphic upwards enrichment in 34S, particularly notable in pyritic and organic S. The sulfur geochemistry of the coal bed is interpreted as having been influenced by late depositional or post-depositional incursion of sulfate-rich waters into the peat, indicating a change in depositional environment. The coal delivered to the power plant over two weeks does show variations in S composition. The coal delivered during week 1 had higher total sulfur and pyritic S contents and more enriched bulk *34S values than the coal delivered during week 2. In contrast, the *13C of the coal delivered during week 1 is only slightly more enriched than the coal delivered during week 2, though with such a small sample set, this is probably not significant. The pulverized coal, which is the fuel injected into the boiler, has *34S and *13C values similar to the average value of the power plant feed coal. The pulverizer reject has much higher pyrite content than the pulverized coal and more enriched *34S values. With the exception of the last row of the ESP, which collects a fraction of a percent of the total fly ash, there is a slight increase in *34s from the hotter end of the collection system to the cooler rows. With a decrease in temperature, therefore, there is increased fly ash enrichment in 34S and flue gas depletion in 34S. The observed fractionation in S isotopes is consistent with a study conducted at a power plant burning higher S coal than the plant in this study. Despite the significant difference in carbon content, only a small enrichment of 0.44 to 0.67%c in 13C in the ash relative to the coal is observed, demonstrating that fractionation of C isotopes in the boiler and convective passes, prior to the arrival of the fly ash in the ash-collection system, is minor. No significant difference in *13C values among the rows of the fly ash-collection system was detected, further confirming that the partitioning preceded arrival of the flue gas in the pollution-control system.
|Title of host publication||23rd Annual International Pittsburgh Coal Conference, PCC - Coal-Energy, Environment and Sustainable Development|
|State||Published - 2006|
|Event||23rd Annual International Pittsburgh Coal Conference, PCC - Coal-Energy, Environment and Sustainable Development - Pittsburgh, PA, United States|
Duration: Sep 25 2006 → Sep 28 2006
|Name||23rd Annual International Pittsburgh Coal Conference, PCC - Coal-Energy, Environment and Sustainable Development|
|Conference||23rd Annual International Pittsburgh Coal Conference, PCC - Coal-Energy, Environment and Sustainable Development|
|Period||9/25/06 → 9/28/06|
Bibliographical noteFunding Information:
The authors thank the anonymous reviewer for their helpful suggestions for the improvement of this manuscript. The original mine and power plant study was funded by the National Coal Quality Inventory (NaCQI), administered by the US Geological Survey, to the University of Kentucky CAER. Sarah Mardon was supported by NaCQI funding and by a grant from CONSOL Energy in support of undergraduate research.
Copyright 2008 Elsevier B.V., All rights reserved.
ASJC Scopus subject areas
- Energy Engineering and Power Technology
- Condensed Matter Physics