COAL TIRE COLIQUEFACTION USING AN IRON SULFIDE CATALYST IMPREGNATED IN-SITU IN THE COAL

The coliquefaction of coal with discarded tire rubber is studied at 10 00 psig (cold) of hydrogen and 400 degrees C using a hva bituminous co al in the presence of an impregnated iron sulfide catalyst, without ad dition of a sulfiding agent. The base case is a noncatalytic coliquefa ction under the same conditions. The catalyst shows activity comparabl e to other catalysts commonly used for direct coal liquefaction (DCL) under the conditions used here. The values of the conversion and yield , when using the tire as solvent, differ from the corresponding values when a facile hydrogen-donating solvent such as tetralin is used. How ever, these differences diminish in the presence of the iron sulfide c atalyst, under the conditions studied. Even at Fe levels as low as 110 0 ppm in coal, the catalyst greatly improves the coal conversion, from 44% (in the base case) to 60%. The liquefaction rate is first-order d ependent on the catalyst loading and first-order dependent on the rubb er tire loading. Impregnation of the total amount of catalyst on only 12% of feed coal (to the reactor) achieves the same coal conversion as when 100% of the feed coal is impregnated with the same total amount of catalyst. This is significant because it implies that only a small fraction of the feed coal in a large-scale operation needs to be subje cted to the catalyst impregnation process. The presence of the byprodu ct sodium chloride from the formation of the iron sulfide catalyst doe s not significantly affect catalyst performance. This is a significant result because it implies that extremely rigorous washing of the impr egnated coal is not essential for commercial-scale operation of this p rocess.