Coal hydropyrolysis with dispersed catalysts

Several coals were subjected to hydropyrolysis in the presence of catalysts to study the possibility of coal liquefaction without added solvent. Iron compounds, nickel compounds and ammonium tetrathiomolybdate were investigated as potential catalyst precursors. When the precursor was water soluble, an incipient wetness method was used to impregnate the coal with the precursor. Reactions were carried out in tubing reactors at 350°C-400°C under a 2000 psig dihydrogen atmosphere.;Only molybdenum showed significant catalytic activity at 350°C. The most active iron compound tested was ammomnium iron(III) sulfate which was only moderately active at 400°C. Nickel was more active than iron and molybdenum was the most active. Only a very small amount of molybdenum (0.05 wt% of coal) was sufficient to achieve hydropyrolysis of the Blind Canyon coal at 400°C with molybdenum and molybdenum-iron catalysts. The liquid yields from hydropyrolysis were close to 80 wt% of the moisture-ash-free coal and the total conversion to gases and liquids was over 90% for the Blind Canyon coal. A small amount of nickel (0.005 wt% of coal) was effective in promoting catalytic activity of molybdenum and reduced the amount of molybdenum required to 0.03 wt% of the Blind Canyon coal.;Incipient wetness impregnation could be used successfully to introduce catalyst precursors to coal as shown by the high conversion of coal. EPMA (Electron Probe Microanalysis) micrographs also showed that the catalysts were dispersed throughout the coal. The EPMA micrographs also suggested that the molybdenum was in the sulfided form.