98/00372 Assessment of coal-water slurry fuels for electric power generation in Southern Indiana. Part 1. Detailed resource characterization

Abstract

Impounded coal fines, a by-product of wet coal preparation techniques, are a potential fuel resource for electric power generation due to their abundance and characteristics when burned as a coal-water slurry fuel (CWSF). Recent work by the Pennsylvania Electric Company and others has shown that co-firing CWSF composed of cleaned material from slurry impoundments can reduce emissions of nitrogen oxides by as much as twenty percent. The commercial reality of using impounded coal fines as a CWSF depends more on coal cost, processing requirements, and the value of emission reduction credits than on the quality or abundance of the material. Many Southern Indiana slurry impoundments, including those selected for characterization in this study, contain over one-million tons of fine coal. The older impoundments have a higher percentage of coarse coal. One impoundment filled prior to 1975 averages fifty percent coal particles greater than 30 mesh (600 {mu}). Improvements in preparation plant fine coal recovery circuits are reflected by an increasing percentage of less than 200 mesh (75 {mu}) coal in more recently filled impoundments. Another impoundment filled in 1995 averages forty-nine percent coal and mineral particles finer than 200 mesh. Bench scale sink/float testing showed that separating particles with amore » specific gravity greater than 1.7 produced a fine coal with ten percent ash and three percent sulfur. This is similar in quality, but finer in particle size, to the coal currently used in a typical coal fired power station burning typical Illinois Basin coals. Detailed characterization of two inactive impoundments highlighted the differences between coal fines in an older impoundment and one filled in the last ten years.« less