--> ABSTRACT: Sulphur Oxides Mapping and Coal Grade--Finding the Right Coal to Meet Applications and Regulations, by Kenneth C. Ashton, M. E. Hohn, G. H. McColloch, and C. J. Smith; #91023 (1989)

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Sulphur Oxides Mapping and Coal Grade--Finding the Right Coal to Meet Applications and Regulations

Kenneth C. Ashton, M. E. Hohn, G. H. McColloch, C. J. Smith

The role of coal quality in combustion use involves evaluating many parameters to determine the correct grade (the interaction of different quality parameters) of coal for a particular application. An important consideration is the amount of sulfur oxides (SOx, primarily SO2) released during combustion. SOx is measured in pounds per million Btu and is used to determine new source standard compliance coals. Under present regulations, compliance coals produce less than or equal to 1.2 lbs of SOx per million Btu and may be burned in new boiler units with no sulfur emission reduction equipment.

West Virginia has a vast range of coal grades within its 62 mineable coal seams. Higher grades generally occur in the southern coalfields and have lower sulfur and higher Btu values. Although these coals may be compliance coals in term of SOx producing potential, many may not be best suited for pulverized coal combustion applications due primarily to the high ratio of fixed carbon to volatile matter. Coals with a high carbon/volatile matter ratio burn hotter. However, they also tend to be harder to ignite (coals with a high volatile content are easier to ignite), which may cause them to burn less efficiently in pulverized coal furnaces (like those used by many electric utilities) where residence time is short and ignition must occur quickly. However, blends using these high r ranked coals have worked effectively in some plants.

Many coal-quality parameters affect the method in which a coal may be best used. At the West Virginia Geological Survey, we attempt to match the optimum grade of coal to any given application. This match is achieved by mapping quality parameters such as pounds of SOx per million Btu then combining several coal quality maps to determine probable locations of a specific grade. This procedure enables us to better categorize our coals for their optimum use potential.

AAPG Search and Discovery Article #91023©1989 AAPG Eastern Section, Sept. 10-13, 1989, Bloomington, Indiana.