Catalytic hydrogen transfer due to FeSO 4 and Co&z.sbnd;Mo in coal liquefaction

Abstract

The liquefaction behaviour of a Kentucky coal was studied in batch autoclave experiments at 410 °C under either a H 2 or a N 2 atmosphere (≈ 13.8 MPa) for reaction times of up to 2 h. To understand the catalytic roles of FeSO 4 and a Co&z.sbnd;Mo catalyst in coal liquefaction and to assess the feasibility of using FeSO 4 as a model for coal pyrites, effects of impregnation of the coal with FeSO 4 and direct charges of a Co&z.sbnd;Mo catalyst on coal liquefaction and tetralin dehydrogenation were examined. Both catalysts increase the conversion to benzene-soluble material by 7–10%, and improve the selectivity values for conversion to oil and gas. In addition they are also active in the dehydrogenation of tetralin. The dehydrogenation activities of these catalysts correlate with their catalytic activities during coal liquefaction. Analyses of the mean chemical structures and the product distributions of the coal-derived liquid from liquefaction in H 2 and in N 2 atmospheres indicate that: 1. (1) H-transfer from tetralin is the only major mechanism of coal liquefaction; and 2. (2) both pyrrhotite, generated in-situ from FeSO 4, and Co&z.sbnd; Mo catalyst can provide a major liquefaction mechanism by catalysing the H-transfer from the donor solvent to the coal or the coal-derived liquid.