Catalytic activity of various iron sulphides in coal liquefaction

Abstract

Iron sulphides with various S-Fe atomic ratios, such as pyrite, iron(III) sulphide, pyrrhotite and troilite, were used as catalysts for coal liquefaction. Catalytic activities were compared on the basis of the temperature of the exothermic peak due to coal hydrogenolysis. Effects of hydrogen sulphide on catalytic activity of iron sulphides were also investigated. It is concluded that: 1. 1. The catalytic activity of iron sulphides increases with increasing S-Fe ratio; 2. 2. pyrite, with the highest catalytic activity, is converted to pyrrhotite before the onset of exothermic reactions from coal hydrogenolysis, this evidently being the reason for the high catalytic activity; 3. 3. the catalytic activity of iron sulphides depends on the coal type; 4. 4. the high catalytic activity of pyrite may be due to the creation of fresh pyrite surface during the reaction rather than to the presence of high concentrations of hydrogen sulphide.