High-Sulphur Shale Oil as a Prime Matter for Bitumen Production

Abstract

The composition and properties of heavy residues of Israeli shale oil (S content 6.8 %) were investigated as a source for bitumens. Both principal methods of asphalt productionvacuum distillation and oxidizing with airwere studied. Straight-run bitumen had satisfactory characteristics. As to oxidized bitumen, the values of its penetration, ductility and softening point were also satisfactory. The drawback of shale oil bitumens is their high viscosity after the thin film oven test, which means their high sensitivity to aging. The shale oil composition changes significantly as a result of distillation and oxidation. The content of asphaltenes sharply increases: from 3.5 to 20-22 % in straight-run bitumen and to 30 % in oxidized bitumen. It is explained by the reactions of condensation and polymerization of the most unstable polar components during heating and oxidation. Unlike petroleum, shale oil is a product ofpyrogenic origin, i.e., it is formed as a result of thermal decomposition of large molecules of kerogen and a part of this cracked material consists of unstable fragments of these molecules, which have a tendency to polymerization. The C/H ratio and nitrogen content increase significantly т the order "saturated hydrocarbonsnaphthenoaromaticsaromaticsasphaltenes".