THE EFFECT OF COAL BENEFICIATION AND SWELLING ON LIQUEFACTION BEHAVIOR OF BLACK-THUNDER COAL

Liquefaction experiments were undertaken using subbituminous Black Thu nder mine coal to observe the effects of aqueous SO2 coal beneficiatio n and the introduction of various coal swelling solvents and catalyst precursors. Aqueous SO2 beneficiation of Black Thunder coal removed al kali metals and alkaline earth metals, increased the sulfur content an d increased the catalytic liquefaction conversion to tetrahydrofuran ( THF) solubles compared to untreated Black Thunder coal. The liquefacti on solvent had varying effects on coal conversion, depending upon the type of solvent added. The hydrogen donor solvent, dihydroanthracene, was most effective, while a coal-derived Wilsonville solvent promoted more coal conversion than did relatively inert 1-methylnaphthalene. Sw elling of coal with hydrogen bonding solvents tetrahydrofuran, isoprop anol, and methanol, prior to reaction resulted in increased noncatalyt ic conversion of both untreated and SO2 treated Black Thunder coals, w hile dimethyl sulfoxide (DMSO), which was absorbed more into the coal than any other swelling solvent, was detrimental to coal conversion. S welling of SO2 treated coal before liquefaction resulted in the highes t coal conversions; however, the untreated coal showed the most improv ements in catalytic reactions when swelled in either THF, isopropanol, or methanol prior to liquefaction.