Effect of solvent swelling and catalyst impregnation on the liquefaction of Black Thunder coal

The effect of swelling untreated and SO2-treated Black Thunder coals on coal liquefaction behavior was investigated. Catalyst precursors including Molyvan L, molybdenum naphthenate, and nickel octoate were introduced into swelling solvents consisting of tetrahydrofuran (THF), isopropanol, or methanol at typical loadings of 700 ppm of active metal. Coal liquefaction reactions were performed at 385 and 410 degrees C using 1-methylnaphthalene, dihydroanthracene, or coal-derived V1074 as liquefaction solvents. The efficacy of the process was measured by using coal conversion to THF-soluble materials. Pyrene was added to the liquefaction feed to provide a measure of catalyst hydrogenation activity. Swelling of coal in the presence of a catalyst prior to liquefaction should increase the accessibility of the interstitial structure to the catalyst and, therefore, increase coal reactivity at liquefaction conditions; however, this concept was valid with only one catalyst system. Only the addition of molybdenum naphthenate with added excess sulfur resulted in improved conversion of Black Thunder (WY sub-bituminous) coal. No improvement with the addition of either Molyvan L or nicker octoate was observed. The addition of all of the catalyst precursors resulted in increased pyrene hydrogenation; therefore, there was not a direct correlation of hydrogenation and coal conversion catalytic activities.