No abstract

In this paper, the effects of sulfur on liquefaction performances of coal and the transformation behaviors of γ-Fe 2 O 3 at the S/Fe atomic ratio of 0-1.3 under mild conditions were investigated. Compared with traditional liquefaction processes, the oil yield and coal conversion were insensitive to the addition of sulfur under mild conditions (temperature of 430°C, reaction pressure of 8.5-13.8 MPa). The optimum S/Fe atomic ratios at the initial H 2 pressures of 4.0 and 8.0 MPa were 0.6 and 1.0, which were lower than those of traditional liquefaction processes. As the S/Fe atomic ratio increased from 0 to 0.6 (at the initial H 2 pressure of 4.0 MPa), the oil yield and coal conversion increased by 4.0% and 3.8%, and this could be attributed to the synergistic effects between the relatively sulfur-rich structure of pyrrhotite (Fe 0.8917 S) and the relatively high partial pressure of H 2 S. In addition, over 85% of sulfur was retained in the solid products, and the effect of S/Fe atomic ratio on the sulfur distribution was tiny. However, increasing H 2 pressure was conducive to the transfer of sulfur to the gaseous products.