Advanced coal liquefaction research. Quarterly technical progress report, July 1, 1983-September 30, 1983

Work this quarter focused on staged liquefaction. The effect of residence time on conversion in single pass experiments was found to be quite different for the subbituminous Belle Ayr Mine and bituminous Illinois No. 6 coals studied. With bituminous coal, conversion to soluble material is quite high and the limit of conversion is approached in only a few minutes. With a subbituminous coal, however, conversion is much lower and the limit of conversion is approached much more slowly. Short contact time (SCT) dissolution of Belle Ayr coal was studied as a possible first stage in a two-stage process. Conversion, hydrocarbon gas yield and hydrogen consumption were increased as residence time or temperature were increased. Conversion was also significantly increased by partial slurry recycle. Pyrite was found to be the most effective slurry catalyst for increasing conversion, followed by ammonium molybdate emulsion and finally nickel-molybdenum on alumina. Illinois No. 6 coal was liquefied in two stages. Conditions in the first stage dissolution were varied to determine the effect on upgradability in the second stage. An SCT (6 minute) coal dissolution stage is preferred over one at 30 minutes because hydrocarbon gas yield was much lower while overall oil yields for the combined dissolution and upgrading stages were nearly the same. Use of a NiMo/Al/sub 2/O/sub 3/ catalyst in a trickle-bed second stage resulted in a higher oil yield and lower product heteroatom content than use of the same catalyst in the slurry phase. The total oil yield was lower with a pyrite slurry catalyst than with a NiMo/Al/sub 2/O/sub 3/ slurry catalyst. With Belle Ayr coal and added pyrite, there was no change in total oil yield, conversion or product quality brought about by adding an 8-minute first stage at 450/sup 0/C (842/sup 0/F) to a 2-hour second stage operated at 420/sup 0/C (788/sup 0/F). 39 figures, 12 tables