Catalytic Upgrading of Solvent-Refined Lignite Using Hydrogen Sulfide and Prepared Iron Oxide-Supported Catalysts

摘要

This paper discusses a catalytic system, H sub 2 S-iron system that shows promise as an economical means of upgrading the heavy product from low-temperature direct liquefaction of low-rank coal. Four conclusions can be drawn from this study: (1) Product quality during catalytic upgrading with the H sub 2 S-iron system was increased significantly at 420 exp 0 C when compared with 360 exp 0 C. (2) When H sub 2 S and iron catalyst were not present in the system, thermal treatment of the soluble residuum at 420 exp 0 C had no measurable beneficial effect. (3) Hydrogen sulfide worked primarily through the distillate. (4) Iron worked primarily through the heavy fraction of the recycle solvent. The mechanism involved hydrogen addition, as was evidenced by the increased H/C ratio. When these observations are added to previously reported data which indicated that added H sub 2 S improves distillate yield, lowers gas yield, and improves operability in CPU recycle operation, it suggests that H sub 2 S acts directly with the lighter fractions of the recycle solvent. In doing this H sub 2 S acts to improve solvent quality, which indirectly improves conversion of the heavier fractions. This type of solvent quality enhancement can explain the lower gas yield associated with added H sub 2 S. It also supports the previously referenced data which indicated that when iron additives were added during recycle operation, with no added H sub 2 S, product quality as measured by H/C ratios was improved but operability was not. This preliminary evaluation of H sub 2 S-iron catalysis points to additional areas for research, in both catalyst systems and their applications. 16 refs., 8 figs., 5 tabs. (ERA citation 10:038641)