Direct Liquefaction of High-Sulfur Coals: Effects of the Catalyst, the Solvent, and the Mineral Matter
Gözmen, Belgin
Two low-rank coals with high sulfur contents (Gediz subbituminous coal: 7.6 wt % S:dry basis. Çayirhan lignite: 5.7 wt% S:dry basis.) were subjected to hydroliquefaction. Liquefaction conditions included dry or solvent mediated runs under pressurized hydrogen without added catalyst or with the impregnated catalyst precursor ammonium heptamolybdate (AHM). Gediz coal having higher sulfur content gave 90% conversion in the absence of catalyst and solvent. Maximum conversion (98%) and maximum oil + gas yield (70%) from this coal were obtained by impregnating AHM onto coal and carrying out liquefaction in H2/tetralin system at 450 °C for 30 min. Under the same conditions, Çayirhan lignite gave 85% conversion and 70.5% oil + gas yield. The superior hydrodesulfurization effect of impregnated AH...