Utilization of high sulfur coals by self-scrubbing

Abstract

High sulfur coal states, such as Indiana, Illinois, and Ohio, are struggling with a dilemna that has surfaced with the enactment of the 1990 Clean Air Act Amendments (CAAA). These three states are among the top ten in the categories of coal consumption and existing coal reserves. However, even after the high sulfur coal from these mid-western states are cleaned in conventional coal preparation plants, it still does not meet the emission limitation [.52 kg SO 2 /GJ (1.2 lbs SO 2 /MMBtu)] that the CAAA mandate for the year 2000. In order to address this issue, most utilities plan to switch to low sulfur coal from the Western U.S. and Central Appalachian region or install scrubbers. Since coal generates almost 60 percent of the nation's electricity and utilities consume 80 percent of the nation's coal, the choices made by the utility companies to comply with the CAAA is of great concern to many interest groups. Switching to low sulfur coals from outside the region puts local miners out of work and weakens the economy in the utility's service territory. Scrubbing, which many high sulfur state governments (namely, Illinois) advocate to preserve local mining operations, requires a major capital expenditure by the utility. Scrubbers also increase the operating complexity and costs of the generating station and produce yet another environmental problem - scrubber sludge.