Coal beneficiation and organic sulfur removal

Organic sulfur removal from coal with supercritical methanol as solvent, combining extraction and reaction, was studied. Experiments were carried out in a 300 mi batch reactor with Illinois coal at a coal/methanol weight ratio of I : 1, 400-450 degrees C and various solvent densities and reaction times. Coal loss, similar to 25 wt%, was relatively insensitive to operating conditions. Sulfur removal was highest at low solvent density and high temperature, ranging, for 15 min reaction time, from 34 to 53% on a feed-to-product basis, or up to 66% if loss of coal is allowed for. Initial results obtained with a semicontinuous reactor are briefly summarized, as well as recent work on oil agglomeration at low oil levels followed by flotation.