Investigation of Structural Phase Conversions of an Iron-Containing Catalyst by Mossbauer Spectroscopy (Part 1)

The active form of an iron-containing catalyst including mixed Fe(II, III) oxides for refi ning Ashal′cha heavy oil was investigated using Mossbauer spectroscopy to establish the formation mechanism. The iron-oxide phase is involved during the formation process in the cleavage of carbon-heteroatom bonds in asphaltene and resin fractions of heavy oil and decreases their molecular masses. The disperse iron oxides are enriched in a sulfur-containing phase. The conversion degree of the compounds increases as the duration of the experiment increases, which indicates that the disperse iron compounds participate multiple times in the cleavage of chemical bonds. Results of Mossbauer spectroscopy indicate that maghemite is reduced to magnetite when the iron oxides react with water vapor during the catalytic aquathermolysis of crude oil at 250°C.