Extraction of potential pollutants from Ohio coal by synergistic use of supercritical fluids. Final report

Abstract

A synergistic supercritical extraction process was developed and its feasibility demonstrated using a semi-batch extraction process unit. The process was found to be effective in selectively cleaning organic sulfur from Ohio coals. Optimal case involved a mixture of CO{sub 2}, H{sub 2}O, and CH{sub 3}OH, and the removal of organic sulfur ranged from 35 to 55%. Combined with pyrite and mineral matter removal by gravity, the resulting coals would have 20--30% increased heating values and SO{sub 2} emissions would be down to 1.2--1.5 pounds per million Btu, thus meeting compliance requirements. Estimated cleaning cost including pyrite removal is $25 to 45 per ton. The most important cost factor is the operation at high pressures.