TEMPERATURE-STAGED LIQUEFACTION OF COALS IMPREGNATED WITH FERROUS SULFATE

Two coals, a high volatile A bituminous coal from Utah and a subbituminous coal from Texas, were subjected to temperature-staged liquefaction in hydrogen and hydrogen/hydrogen sulfide atmospheres. Addition of H2S to the reaction gas increased the conversion of both coals, through higher asphaltene yields from the bituminous coal and higher yields of all liquid products from the subbituminous coal. Generally the addition of ferrous sulfate to the coals, followed by liquefaction in hydrogen, had about the same effect as addition of H2S to the gas, though the systems with added FeSO4 had lower yields of preasphaltenes than obtained by use of H-2:H2S. The addition of H2S to the gas combined with impregnation with FeSO4 provided significant enhancement of conversion of both coals. For both coals the effect of using the two additives together was to enhance the asphaltene yields. The results of this work suggest the possibility of selectively tailoring the behavior of the catalyst in different stages of the liquefaction process by selecting the appropriate gaseous atmosphere.