Catalytic effects of iron compounds and the role of sulfur in coal liquefaction and hydrogenolysis of SRC

Abstract

Effective iron catalysts in coal liquefaction have been explored. Reduced Fe, Fe(CO) 5, and ferrocene have shown a considerably high catalytic activity in the liquefaction of Yallourn coal at 400°C. Degree of reduction has been shown to be one of the most important factors determining the catalytic activity of the iron catalyst. In the hydrogenolysis of SRC derived from Wandoan coal, water formed in situ has been shown to exhibit a negative effect due to reoxidation of the iron catalyst, but addition of elemental sulfur is greatly effective in preventing such deleterious influence of water. This can be interpreted on the basis of the sulfidation of reduced Fe by elemental sulfur, competing with reoxidation of the iron catalyst by water. In the systems with elemental sulfur, active and oxidation-proof pyrrhotite is formed, and the degree of reduction of the remaining iron oxide is maintained higher than that in the absence of elemental sulfur.