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Intra- and inter-unit variation in fly ash petrography and mercury adsorption: Examples from a western Kentucky power station

Energy and Fuels

By:
, , ,
DOI: 10.1021/ef9901488

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Abstract

Fly ash was collected from eight mechanical and 10 baghouse hoppers at each of the twin 150-MW wall-fired units in a western Kentucky power station. The fuel burned at that time was a blend of many low-sulfur, high-volatile bituminous Central Appalachian coals. The baghouse ash showed less variation between units than the mechanical hoppers. The mechanical fly ash, coarser than the baghouse ash, showed significant differences in the amount of total carbon and in the ratio of isotropic coke to both total carbon and total coke - the latter excluding inertinite and other unburned, uncoked coal. There was no significant variation in proportions of inorganic fly ash constituents. The inter-unit differences in the amount and forms of mechanical fly ash carbon appear to be related to differences in pulverizer efficiency, leading to greater amounts of coarse coal, therefore unburned carbon, in one of the units. Mercury capture is a function of both the total carbon content and the gas temperature at the point of fly ash separation, mercury content increasing with an increase in carbon for a specific collection system. Mercury adsorption on fly ash carbon increases at lower flue-gas temperatures. Baghouse fly ash, collected at a lower temperature than the higher-carbon mechanically separated fly ash, contains a significantly greater amount of Hg.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Intra- and inter-unit variation in fly ash petrography and mercury adsorption: Examples from a western Kentucky power station
Series title:
Energy and Fuels
DOI:
10.1021/ef9901488
Volume
14
Issue:
1
Year Published:
2000
Language:
English
Publisher:
ACS
Publisher location:
Washington, DC, United States
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Energy and Fuels
First page:
212
Last page:
216
Number of Pages:
5